Brachytherapy use in cervical cancer: a narrative review

Introduction

Background

Cervical cancer is the second-most common cancer among women worldwide, affecting over 570,000 women worldwide, and resulting in over 311,000 deaths (1,2). Although its incidence has decreased worldwide over the past 50 years, it remains a leading cause of cancer death in the developing world (1,2). According to the American Society for Radiation Oncology (ASTRO), the currently recognized treatment standard for locally advanced cervical cancer is external beam radiation therapy (EBRT), which is a non-invasive procedure that uses high-energy particles delivered from a machine outside the body to target cancerous tissues, with concurrent chemotherapy and brachytherapy (3,4). The EBRT, typically delivered via intensity modulated radiation therapy (IMRT), allows for an initial reduction in tumor size, allowing for more targeted and efficient brachytherapy afterwards (2,3,5).

Brachytherapy is a form of internal radiation therapy in which radioactive sources are placed directly within or adjacent to the tumor, allowing high doses to be delivered to the target while minimizing exposure to surrounding organs (2). Unlike EBRT, which treats a broader pelvic field, brachytherapy provides the dose escalation needed to control the primary tumor (6). Historically, brachytherapy was performed using two-dimensional (2D) planning based on anatomical landmarks, meaning that physicians estimated where the tumors were based on fixed reference points, not accounting for patient-specific tumor shapes (6). Therefore, limitations of this approach became apparent in patients with irregular or bulky tumors (3). Thus, the planning and administration of brachytherapy has undergone a significant transformation with the introduction of magnetic resonance imaging (MRI)- and computed tomography (CT)-guided three-dimensional (3D) image-guided brachytherapy (IGBT) (6,7). This evolution has expanded the precision, safety, and effectiveness of brachytherapy, particularly in patients with large, irregular, or asymmetric tumors (6,8).

Rationale and knowledge gap

Despite the improvements that have been made in brachytherapy practice, there remains variation across institutions around the world in technique, as differences in imaging modality access, operator training, applicator availability, and institutional capabilities/workflow contribute to a lack of uniformity in adoption of the newest techniques (3,8).

Furthermore, although broadly speaking, indications are clear regarding when to use which brachytherapy technique may seem obvious, the real-world clinical decision-making often lacks consensus or precision in the intermediate cases. This raises a need for clinical guidance on when and why to use the three major types of brachytherapy: intracavitary brachytherapy (ICBT), interstitial brachytherapy (ISBT) and hybrid intracavitary/interstitial brachytherapy (hybrid IC/IS-BT) (2,6).

Objective

The objective of this article is to narratively review the clinical evolution of cervical brachytherapy techniques—including intracavitary, interstitial, and hybrid approaches—and to outline their respective advantages and limitations. Furthermore, this review seeks to examine how specific clinical and imaging findings, such as tumor size, shape and broader resource availability, inform optimal treatment modality selection. Thus, such a review can aid in supporting gynecologic oncologists to make more streamlined referral decisions and better understand post-treatment expectations. We present this article in accordance with the Narrative Review reporting checklist (available at https://gpm.amegroups.com/article/view/10.21037/gpm-25-44/rc).

Methods

This literature search conducted on June 10, 2025 focused on a global search of review articles, prospective trials, retrospective studies, and guideline documents written by different radiation oncology departments that were found on PubMed between January 1, 2000 to December 31, 2024. Articles were found through the use of key terms and Boolean operators such as “cervical cancer” AND “brachytherapy” OR “high dose rate brachytherapy” OR “intracavitary brachytherapy” OR “interstitial brachytherapy” OR “hybrid brachytherapy”. Articles were selected based on their clinical relevance to brachytherapy technique and clinical selection criteria (Table 1). The selection was done by Dr. Subhakar Mutyala through independent review and a consensus discussion was made for final inclusion with all authors. Full-text screening was performed to ensure eligibility, and duplicates were removed. We also used references from the texts retrieved via our literature searches.

The inclusion criteria were English review articles, prospective clinical trials, retrospective studies, and clinical guidelines related to brachytherapy techniques for cervical cancer, while the exclusion criteria included non-English publications and non-peer-reviewed sources, and other articles that were not focused on brachytherapy for cervical cancer.

Evolution, techniques, and clinical outcomes of cervical cancer brachytherapy

Diagnosis and decision-making context

Currently, the management of locally advanced cervical cancer begins with accurate clinical staging, histopathologic confirmation, and radiologic assessment to determine disease extent and guide curative-intending therapy (9). The International Federation of Gynecology and Obstetrics (FIGO) staging system, revised in 2018, provides recommendations for determining the clinical stage of cervical cancer (10). In accordance with the FIGO staging system, the clinical stage is determined conventionally through a pelvic exam, a sigmoidoscopy, and a cystoscopy. Women with a FIGO staging of IB2 to IVA disease, where the tumor extends beyond the cervix but remains confined to the pelvic region, standard management includes brachytherapy as part of their definitive treatment management (2,10). Although not part of formal FIGO staging, MRI (11) and positron emission tomography (PET)-CT (12) are invaluable for brachytherapy planning, offering critical information about tumor size, asymmetry, and high-risk clinical target volume (HR-CTV) definition. The nature in which such imaging is invaluable will be elucidated in the later sections (6).

Radiation therapy is the mainstay treatment in locally advanced cervical cancer when the objective is curative (6). For patients with stage IB2 and above, where tumors are greater than 4 cm, irregular shape, involve parametrial invasion, or have eccentric location located far from the uterine duct, referral for radiation therapy is indicated as primary surgery is typically not recommended due to a high risk of incomplete resection (2,10).

The role of the gynecologic oncologist in early decision-making is crucial not only for diagnosis and determining the FIGO staging, but also for administering systemic therapy (13,14) and possibly assisting in brachytherapy (10,15). The early recognition of a patient who might require advanced, specific brachytherapy techniques such as ISBT, or hybrid therapy is essential for the appropriate coordination of care. This is attributed to the fact that few centers possess true expertise in ISBT, and a timelier referral to a more experienced brachytherapy center can improve patient prognosis (2).

Why radiation therapy? Why brachytherapy?

In patients with locally advanced cervical cancer, definitive chemoradiation—consisting of EBRT and brachytherapy with concurrent chemotherapy—is the globally accepted standard of care (14). EBRT is designed to treat microscopic disease, with this external beam portion of the treatment delivers a dose sufficient to cover the pelvic lymph nodes, parametria, and the primary tumor (2). This radiation of a wider treatment field allows for a dose sufficient coverage of areas where cancer cells might have spread, even if not visibly detected (especially the pelvic lymph nodes and parametria) (10). However effective for widespread microscopic disease and regional coverage, EBRT cannot deliver the very high, localized, tumoricidal doses required to eradicate the gross tumor without large damage to surrounding healthy tissues, organs, which would manifest in severe side effects (2). This is a result of the EBRT radiating larger volumes to intermediate dose levels, thus increasing toxicity without improving local control.

Brachytherapy is thus essential for delivering the higher, tumoricidal doses (greater than 80 Gy) directly to the tumor, serving as a radiation boost to the gross tumor, improving local control and subsequent overall survival (2). By placing a radioactive source near the tumor that follows the inverse square law, it allows for a very high dose to the tumor, while precisely sparing surrounding normal structures such as the rectum and bladder (2). The inverse-square law allows for radiation dose to decrease dramatically with distance from the source, thus protecting nearby organs (2). As a result, even the most precise EBRT techniques such as IMRT and SBRT cannot replace brachytherapy without lowering progression-free and overall survival (4,8). In fact, the retrospective study by Han et al. highlights the concerning trend that reductions in cause-specific and overall survival have been noted with decreasing utilization of brachytherapy for cervical cancer patients (16). Specifically, the EMBRACE I study, a large-scale multi-institutional prospective study using MRI-guided brachytherapy, reported an actuarial 5-year overall survival of 74% (11). Thus, we can say that without brachytherapy, survival drops, emphasizing it as an essential and growing component of locally advanced cervical cancer treatment.

Evolution of brachytherapy techniques

The practice of cervical cancer brachytherapy has evolved dramatically over the past several decades, transitioning from simple 2D planning (17) based on fixed anatomical reference points to highly individualized, image-guided 3D approaches (18). Historically, brachytherapy was performed based on 2D images such as plan film X-rays, with radiation doses prescribed to a reference point known as “point A” (2,8,17). Defined in the Manchester System by Tod and Meredith in the 1930s, point A was originally defined as a location 2 cm superior to the cervical opening (external ostium) and 2 cm lateral to it, along a plane perpendicular to the intrauterine tandem (the rod placed inside the uterus to deliver radiation). This landmark was assumed to approximate the region where the uterine artery crosses the ureter, an area prone to both early tumors spreading and sensitive to radiation injury as defined by Tod and Meredith (19).

Point A was not only intended as a surrogate for the tumor’s likely location but also aimed to represent a point of limiting tolerance—the threshold dose where the maximum effective radiation dose could be given to maximize tumor control, while minimizing damage risk to the sensitive surrounding structures (6,19). Thus, in an age without 3D-guided therapy, it was the standard of care for brachytherapy placement.

As mentioned earlier, brachytherapy used to rely on the 2D images using the point A approach. However, 2D panning had two significant limitations. Firstly, it offered limited visibility of the actual tumor and surrounding organs at risk (OARs) (such as the rectum, bladder, and sigmoid colon) (2). This prescribing of radiation to 2D points rather than 3D volumes often resulted in point A lying either too deep inside the uterus or outside the actual uterus, as every patient’s anatomy differs, especially if the tumor distorts normal pelvic anatomy. Studies by Pötter et al., and Datta et al. highlighted this significant flaw, as a patient’s individual pelvic anatomy was not considered when prescribing radiation, causing unnecessarily high radiation exposure to normal structures (7,20).

This critical flaw in 2D planning underscored an urgent need for better imaging to provide more personalized brachytherapy treatment (2). Thus, as 3D imaging such as CT and MRI were developed, they became incorporated into the treatment paradigm, leading to the introduction of 3D-IGBT, allowing for superior delineation and coverage of the tumor and surrounding organs (8,21). With 3D-IGBT, we can say that large tumors overgrow the brachytherapy given to point A, resulting in recurrences for these tumors in the low-dose brachytherapy regions, indicating that radiation prescription using point A is not enough to consistently achieve local control (6,22). Due to its excellent soft tissue contrast capabilities, MRI became the imaging modality of choice, allowing for the prescription of radiation to larger volumes, such as the HR-CTV, which is defined as the area of gross residual disease at the time of brachytherapy (post-EBRT) (3,6,21). The HR-CTV allows for individualization based on a patient’s pelvic and tumor anatomy, as well as larger and more accurate high-dose radiation coverage, ensuring the actual tumor is adequately covered while minimizing the dose given to healthy structures. This evolution, validated by the EMBRACE I study, a large prospective multi-institutional cohort, found that MRI-guided brachytherapy resulted in excellent local control (a 5-year local control of 92% across all stages), and low rates of severe toxicity when compared to historical controls using 2D/point-A based approaches (11). These findings support the superiority of volume-based planning in achieving tumoricidal doses while sparing surrounding normal tissues.

ICBT

ICBT is primarily suitable for cervical cancer treatment in the early stage and small tumor size, when the position of the mass is symmetrically distributed relative to the uterine cavity, without invasion of the parametrial tissue, and when the HR-CTV is less than 18.8 cm³ (3,23).

When considering the major brachytherapy techniques, the cornerstone technique in the management of locally advanced cervical cancer, specifically for smaller, symmetric tumors, remains ICBT (4). In ICBT, a radioactive source is placed near the tumor by placing an applicator through the vaginal cavity, most commonly using a tandem and ovoids configuration (24). The tandem is a slender, curved rod inserted into the uterus through the endometrial canal, and the ovoids are two oval-shaped components placed laterally in the vaginal fornices beside the cervix to ensure symmetric dose distribution (2). To this day, ICBT remains the most practiced form of brachytherapy for cervical cancer due to its simplicity and non-invasiveness (25). ICBT takes advantage of the aforementioned inverse-square law, allowing for a high dose to the tumor, while largely sparing surrounding healthy structures (2).

Historically, ICBT was performed using lower-dose rate (LDR) sources to emit radiation, such as radium or cesium, which required prolonged treatment times of 1–3 days, necessitating prolonged patient immobilization and hospitalization, and a greater risk of radiation exposure to healthcare personnel (since the providers had to physically insert the source) (2). However, with the advent of high-dose rate (HDR) brachytherapy, there has been increasing adoption of iridium as a radiation source, which has a higher activity level than radium, enabling shorter, more efficient treatment sessions (26). Moreover, HDR uses remote afterloading technology, in which the source is robotically driven through applicator channels to predetermined positions for specific durations based on the 3D planning, allowing for more precise prescription of doses (2). This advancement not only shortened treatment time to minutes across multiple outpatient visits, but also improved radiation safety for staff, who previously had to physically insert the source into the patient (2,8,27).

So, clinically, ICBT is most effective when the tumor is centrally located, symmetrically positioned in the uterus and small or limited to the uterus (3). Its non-invasive nature established applicator systems, and the ability to deliver high central doses with a sharp fall-off make it highly effective in these scenarios. However, ICBT alone becomes suboptimal when the tumor extends asymmetrically into the parametria, as the symmetrical pear-shaped dose distribution cannot adequately encompass the entire target area while respecting dose limits to surrounding OARs (3). Utilizing ICBT for these large or irregularly shaped tumors can lead to underdosing the tumor and a high recurrence rate (3,28). Simulation studies performed by Yoshida et al. support this limitation, showing that larger tumors are better managed with a combined approach rather than by ICBT alone, which will be discussed in further sections (23).

ISBT

ISBT is an advanced form of radiation therapy used in cases where conventional ICBT is insufficient to achieve optimal tumor coverage (8). Unlike ICBT, which relies on a noninvasive method to place a radioactive source using an applicator inside the body’s cavities, ISBT involves the direct placement of catheters or hollow tubes into/around the residual disease using a transperineal/vaginal approach (2,3,29). These catheters allow for the precise insertion of the radioactive sources into the tumor tissue rather than the standard central placement in ICBT (2,29). The technique for ISBT is thus more involved and typically performed in the operating room, under general anesthesia or a combination of spinal/epidural and sedation (30). Multiple techniques are available to guide placement of the catheters, including laparoscopic, fluoroscopic, ultrasound, CT, and MRI guidance (2,30). Due to the ability for the precise placement, ISBT is considered the treatment of choice when intracavitary applicators are deemed unsuitable—for example, in patients with bulky, irregular, or laterally extended tumors according to ABS recommendations (3,30,31).

Specifically, ISBT in indicated in cases involving large tumors, lower vaginal involvement, lateral extension of disease beyond the reach of intracavitary applicators (including cases where the disease develops predominantly on one side), cases where patients aren’t able to have proper fitting intracavitary applicators (such as a patient with an effaced cervix or narrow vaginal fornices), or in patients who develop cancer in the cervical stump (3,30,31). In a 2019 retrospective analysis, Pinn-Bingham reported that ISBT improves locoregional control rate and overall survival, with an 85.3% locoregional control rate, with only 13% of patients suffering grade 3 toxicities (32).

Although ISBT provides conformal insertion based on tumor shape and boundary, leading to more even dose distribution in the tumor area for locally advanced cervical cancer, ISBT alone has deficiencies in central target dose coverage. A study by Bansal et al. found that the mean high-dose volumes covered by ICBT were significantly larger than those covered by ISBT (33). Furthermore, there are various technical challenges for ISBT, as performing ISBT requires precision in needle insertion to avoid complications such as massive bleeding and perforation (3,34,35). For these reasons, ISBT is often reserved for specialized cases and is increasingly being used in combination with ICBT in the hybrid approach, discussed in section “Hybrid techniques (IC/IS-BT)”.

Hybrid techniques (IC/IS-BT)

As brachytherapy has evolved to better address large, asymmetric, or parametrically invasive tumors, hybrid IC/IS-BT has emerged as a critical strategy to bridge the gap between standard ICBT and ISBT approaches (6,36). In cases where ICBT alone is unsuitable or provides inadequate dose coverage, IC/IS-BT is considered the treatment of choice (37). Additionally, while ISBT offers excellent lateral coverage for complex tumor shapes, it may underdose the central cervical region, and hybrid therapy overcomes both limitations by preserving the central dosing of ICBT while adding interstitial needles to address parametrial extension and asymmetry (3,37).

Indications for hybrid therapy are for patients with huge masses or large residual tumors after EBRT, particularly those with an initial diameter greater than 5 cm, or residual tumors larger than 4 cm after EBRT (8,38). Like ISBT, hybrid IC/IS-BT therapy is indicated in patients with incomplete target volume coverage by ICBT, ill-fitting intracavitary applicators, lower vaginal segment involvement, and cervical stump cancer (2,3,37,39). Unique indications include cases where there is poor relative position between the target volume and OARs, as of all the three methods, hybrid techniques allow for optimal dose sculpting, allowing for an increase in tumor dose without significantly escalating OAR doses (2,3,24,40). This capability is enhanced by specific optimization strategies, such as the intentional internal high dose (IIHD) policy HDR-ISBT technique, which aims to maximize dose administration exclusively within the tumor volume while meeting OAR dose limitations (41). In a case study by Kashihara et al., the conventional homogenous dose HDR-ISBT was followed by this IIHD HDR-ISBT technique, and in the subsequent plans, the proportion of the tumor volume receiving 200% of the prescription dose increased by 241% and 204% in the second and third plans, respectively, while the doses to the OARs did not increase. Such a finding indicates that this IIHD HDR-ISBT technique may improve tumor control for bulky tumors (41).

IC/IS-BT utilizes hybrid applicators that combine features of intracavitary and interstitial techniques, requiring fewer needles (but therefore provide a more restricted spatial distribution compared to ISBT) (2). The hybrid applicators are designed to combine the strengths of both ICBT and ISBT approaches. Built on the established designs of intracavitary applicators, the applicator involves placing a radioactive source through the vaginal cavity like done in ICBT, but several interstitial catheters are incorporated in combination with the intracavitary tandem sand ovoid ring/applicator, and these catheters are inserted directly into the tissues, allowing for dose sculpting and more precise dose delivery (2,36,37).

The three major hybrid applicators used—Utrecht-type, Vienna, and Venezia (all manufactured by Elekta AB, Stockholm, Sweden)—each have slightly different needle geometries (the number of available needle channels and direction/orientation of the needles) and orientations, creating slightly different dose coverages (3,36,37,42). These applicators and the hybrid method show improvements in local control, as the EMBRACE I study, a large multicenter prospective study involving 24 institutions, reported an actuarial 5-year local control rate of 92% and in stage IIIB disease, showed an improvement of over 14% compared to historical series using 2D point A-based brachytherapy, while also reporting a low actuarial cumulative 5-year incidence of grade 3–5 morbidities (6,16).

Due to integration with the EMBRACE and other studies, these hybrid applicators are widely recognized, but similar hybrid applicators are also offered by other companies, such as Eckert & Ziegler BEBIG (Berlin, Germany), which produces the Split-Ring, MAC (Mick-Alektiar-Cohen) and Ring Tulip applicators, and Varian Medical Systems (Palo Alto, CA, USA), which produces a range of ring-and-tandem and interstitial applicator sets compatible with VariSource iX and GammaMedplus iX afterloaders (43,44).

Although more invasive, IC/IS-BT has not resulted in more long-term side effects compared to ICBT, and has improved local control, deeming it the treatment of choice when intracavitary applicators are unsuitable (3,6).

Clinical outcomes summary

The clinical efficacy of brachytherapy in cervical cancer has been evaluated across three major approaches—ICBT, ISBT, and hybrid IC/IS-BT—each with distinct advantages and limitations in local control, toxicity, and survival outcomes (Table 2). When combined with EBRT and concurrent chemotherapy, brachytherapy enables a highly conformal tumor “boost” while sparing OARs such as the bladder and the rectum from undue side effects (2,45).

ICBT remains the most practiced form of brachytherapy for cervical cancer due to its simplicity and non-invasiveness (3). It shows particular effectiveness when the mass is symmetrically distributed tumors without parametrial tissue invasion, commonly seen in earlier stage cervical cancer patients (3). For these patients, local control rates can reach 75–95% (3,46). Despite its effectiveness in appropriate scenarios, ICBT faces significant limitations when dealing with locally advanced cervical cancer, with lower local control rates, ranging between 45–80% (47). This emphasizes that since ICBT typically produces a symmetrical pear-shaped dose distribution next to the uterine canal, patients with large tumor size, irregular shape, eccentric location, or severe parametrial invasion cannot use ICBT to deliver an adequate dose to the entire tumor. As a result, these tumors often have high tumor recurrence rates, and alternative approaches such as hybrid IC/IS, or ISBT are indicated (3,48).

A potential alternative to ICBT is ISBT, an invasive method which involves placing catheters directly into/around residual disease using a transperineal or vaginal approach (2,49,50). ISBT offers a significant improvement in locoregional control for larger tumors, especially those with parametrial invasion or lower vaginal involvement (3,40,51). However, it is an invasive procedure performed under anesthesia/sedation and requires technical expertise, carrying a higher incidence of bleeding complications (3,34,35). Furthermore, poor insertion may lead to not only bleeding and perforation, but also underdosing important areas, leading to less desirable patient outcomes (3,34,35). Lastly, the common inability of the dose to cover the central area of the cervix may risk local failure and make it the primary brachytherapy modality in select cases, and if more often used in combination with ICBT, as a hybrid method (3,52).

Hybrid IC/IS-BT combines the central dosimetry of ICBT with the lateral reach of the ISBT, allowing for optimal dose escalation tailored to a patient’s individualized tumor (24). The EMBRACE I study indicated these abilities, demonstrating a 5-year local control rate of 92%, with a less than 5% rate of grade 3–5 late morbidity. This approach, which commonly utilizes 3D imaging as part of planning, has enabled target coverage in tumors that in the past were deemed untreatable (16). This image-guided adaptive brachytherapy (IGABT) combined with IC/IS techniques is also associated with an actuarial 5-year survival and disease-free survival that are superior is historical approaches, while limiting toxicities, indicating that such an approach is the most “flexible brachytherapy, and can be used for the widest variety of clinical scenarios” (2,16).

From a clinical perspective, IGABT using a hybrid IC/IS-BT approach represents the most flexible and comprehensive brachytherapy strategy (2). It provides the optimal combination of achieving locoregional control while limiting toxicities, supporting its growing adoption as the standard of care in complex cervical cancer cases.

Implementation considerations

Although IGABT using a hybrid IC/IS-BT approach is the standard of care for more locally advanced, asymmetric cervical cancers, when implementing such modalities into clinical practice, availability, training, and other resource availability become important to consider (3). Operator and logistics training is vital to perform interstitial and hybrid procedures, brachytherapy, and is a highly user-dependent skill (3). Banerjee and Kamrava detail that there are only a few centers with true expertise in ISBT, and learning such a procedure requires a learning period, with superior outcomes coming at high-volume centers (2,6). Additionally, hybrid IC/IS-BT procedures typically require anesthesia support (general or deep sedation), furthering procedural complexity, staffing needs and overall cost. Therefore, anesthesia availability must also be considered when considering the feasibility of adopting these techniques. In locations where hybrid brachytherapy may not be feasible due to resource limitations, ICBT + IMRT can serve as an alternative after EBRT, as the combination of internal and external fusion irradiation aims to compensate for target areas not covered by ICBT (3). However, IMRT supplementation remains in the theoretical stage of brachytherapy, with a small number of clinical cases performed using this technique showing a potential for a higher toxicity potential (53,54). To continue the spread the hybrid brachytherapy worldwide, continuous education and training are vital for widespread and effective implementation as done in Japan (8,26).

Furthermore, when considering logistical implementation, the choice between HDR and LDR brachytherapy is dependent on clinical workflow and infrastructure capabilities (2,26). HDR brachytherapy, now widely adopted in high-resource settings, uses an Iridium to deliver radiation via remote afterloading systems. Although allowing for outpatient treatment, improved radiation safety and more optimal dose control, it requires access to specialized equipment, software for 3D treatment planning, and trained medical physicists and dosimetrists (2,55). Ultimately, the feasibility of implementing this depends on institutional resources and access to imaging/treatment planning systems, and such factors must be considered when making specific patient referrals for brachytherapy.

In low-resource settings, adaptation of image guidance modality must also be considered (56). In such settings where MRI access is limited, adapting to CT-based or hybrid imaging approaches is a crucial strategy, as CT-based target contouring recommendations for centers lacking MRI exist, but even a diagnostic MRI (without the applicator) allows for consistent HR-CTV contouring, making 3D-IGABT feasible (2,8,21,57). These adaptations expand access to advanced brachytherapy techniques in resource-constrained environments, ensuring that the benefits of 3D-IGABT can be implemented worldwide.

Thus, the ability to select and tailor the optimal brachytherapy modality based on tumor characteristics and institutional resources is vital for effective gynecologic cancer care, especially in areas that may lack specific resources.

Strengths and limitations of this review

This narrative review allows for a clinical integrated discussion across staging, treatment decision-making and technical considerations in brachytherapy. It offers a multidisciplinary perspective, incorporating both radiation oncology evidence and gynecologic oncology decision-making, which is rarely prioritized in brachytherapy literature. By focusing on imaging, tumor characteristics, and synthesizing them with findings from landmark studies and international guidelines, it supports real-world referral and treatment planning decisions.

However, in not being a systematic study, there is a possibility of bias introduction. Due to the qualitative nature of this review, formal statistical analysis is not included. As a result, although widespread applicability was considered, specific implementation recommendations are not complete but rather meant to frame the range of possible treatment pathways and referral decisions.

Evidence strength and study quality

This review integrates findings from numerous original and review articles, with the majority being retrospective or single-institutional. Such variability may reduce the strength of the evidence due to smaller sample sizes and potential selection bias. However, these are a few large prospective multi-institutional trials included—EMBRACE I and GEC-ESTRO—providing high-level evidence supporting the transition to IGABT with limited exposure to OARs. However, even among such trials, differences in imaging modality, dose-reporting metrics, and applicator type make comparison difficult. Moreover, there are limited RCTs comparing intracavitary, interstitial, and hybrid techniques, as tumor geometry dictates technique, such randomization in technique is not feasible, and so current comparisons are observational (2). Consequently, most practice recommendations are derived from prospective cohort data and expert consensus rather than randomized trials. Thus, future research should aim to perform multicenter validation to strengthen evidence for clinical decision-making.

Conclusions

Brachytherapy remains an indispensable component of definitive cervical cancer treatment, and individualized modality selection is essential to achieving optimal outcomes. ICBT remains the standard of care for most cervical cancers, such as small symmetric tumors, while ISBT, and more commonly hybrid IC/IS-BT approaches for locally advanced disease, as they achieve better locoregional control while limiting toxicity. However, widespread adoption of advanced brachytherapy techniques, which include image-guided techniques using MRI or CT (together called IGABT), depends on resource availability and physician training. Lack of adequate provider training or imaging access can lead to an altered optimal modality of brachytherapy used. Improving training, facilitating early gynecologic referral, and adapting imaging protocols for limited-resource settings are crucial steps towards higher-quality brachytherapy care for cervical cancer.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the Narrative Review reporting checklist. Available at https://gpm.amegroups.com/article/view/10.21037/gpm-25-44/rc

Peer Review File: Available at https://gpm.amegroups.com/article/view/10.21037/gpm-25-44/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://gpm.amegroups.com/article/view/10.21037/gpm-25-44/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

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