Impact of intracavitary brachytherapy technique (2D versus 3D) on outcomes of cervical cancer: a systematic review and meta-analysis

Brachytherapy Workflow Practices: Analysis of Different Workflow Scenarios in Patients With Cervical Cancer and Impact on IGBT Implementation-An IAEA Study

PURPOSE

The workflow of brachytherapy (BT) is an essential aspect of treatment to consider in image-guided brachytherapy (IGBT). It has an overarching effect influencing patient throughput and the number of cancer treatments that can be performed as it occupies equipment, space, and personnel. There is limited research addressing this issue. Under the International Atomic Energy Agency's Coordinated Research Activity titled IGBT for cervix cancer: An implementation study, our study analyzes various scenarios in the clinical workflow of BT delivery for cervical cancer. It aims to determine the extent to which these scenarios allow the routine implementation of IGBT. With this information, current barriers and individualized adaptations to efficient workflows can be identified to enhance the global application of IGBT, leading to better cervical cancer treatment.

MATERIALS AND METHODS

A web-based poll of questions regarding practices in BT workflow was presented to 62 participants from low-, lower middle-, upper middle-, and high-income countries (19 countries).

RESULTS

This study highlighted diversity in BT practices across countries, income levels, and regions. It identified variations in workflow, patient throughput, and resource availability, which can have implications for the efficiency and quality of BT treatments. Scenario A, utilizing multiple locations for the steps of the BT procedure, was the most commonly used. The availability of resources, such as imaging devices and trained personnel, varied among the participating centers and remained challenging for IGBT implementation and sustainability.

CONCLUSION

The design of the BT facility plays a vital role in improving efficiency, with a dedicated BT suite contributing to an efficient workflow but limiting patient throughput, especially for high-volume centers. Although IGBT is effective, its implementation requires consideration of various logistical challenges and should be individualized.

Radiotherapy for postoperative vaginal recurrences of cervical squamous cell carcinoma: analysis of dosing and prognosis

Squamous cell carcinoma (SCC) is the most common type of vaginal recurrence in cervical cancer patients, and the role of salvage radiotherapy on these patients remains unclear. This study aimed to investigate the efficacy of salvage radiotherapy for vaginal recurrence of SCC in patients who previously underwent surgery and to explore prognostic factors associated with survival. Ninety-seven patients with histologically proven SCC who were treated for vaginal recurrence at Peking Union Medical College Hospital were identified. All patients had previously undergone surgery and received salvage radiotherapy. Factors predictive of overall survival (OS), progression-free survival (PFS), and local control (LC) were investigated. The median follow-up time was 42.5 months. The estimated 5-year OS, PFS, and LC rates were 84%, 79%, and 91%. On multivariate analysis, inguinal lymph node metastasis was significantly associated with poor OS; a tumour size ≤4 cm was associated with longer PFS (p < 0.05); the recurrence pattern was an independent predictor of LC (p < 0.05). In the 45 patients with recurrences that were paravaginal or invasive of surrounding organs, biologically equivalent doses in 2 Gy fractions of ≥72.6 Gy were independently predictive of longer LC (p < 0.05). RT is an effective treatment for postoperative vaginal recurrence in patients with cervical SCC. For patients with extravaginal recurrence, a salvage dose of ≥72.6 Gy appears to be optimal.Impact statementWhat is already known on this subject? Radiotherapy plays a critical role in treating recurrent cervical cancer, but the effectiveness of RT for vaginal recurrence in patients who previously underwent surgery remains limited. Few studies have focussed on the effect of RT dose on patient survival.What do the results of this study add? This study investigated the efficacy of RT in patients with cervical squamous cell carcinoma who experienced postoperative recurrence. Lymph node metastasis, tumour size and recurrence pattern were significantly associated with survival. Moreover, an EQD2 ≥ 72.6 Gy was independently predictive of longer LC.What are the implications of these findings for clinical practice and/or further research? RT is an effective treatment for postoperative vaginal recurrence in patients with cervical squamous cell carcinoma. For patients with extravaginal recurrence, a salvage dose of ≥72.6 Gy appears to be optimal.

Safety and Efficacy of 2D Brachytherapy vs. 3D Image-Guided Adaptive Brachytherapy for Locally Advanced Cervical Cancer-A Single Institution Retrospective Study

BACKGROUND

The treatment paradigm for locally advanced cervical cancer (LACC) has shifted from two-dimensional-brachytherapy (2D-BT) to three-dimensional-image-guided adaptive BT (3D-IGABT). In this retrospective study, we report our experience with the change from 2D-BT to 3D-IGABT.

METHODS

We reviewed 146 LACC patients (98 3D-IGABT and 48 2D-BT) who received chemoradiation between 2004 and 2019. The multivariable odds ratio (OR) for treatment-related toxicities and hazard ratios (HR) for locoregional control (LRC), distant control (DC), failure-free survival (FFS), cancer-specific survival (CSS) and overall survival (OS) are reported.

RESULTS

The median follow-up was 50.3 months. There was a significant decrease in overall late toxicities in the 3D-IGABT group compared to the 2D-BT group (OR 0.22[0.10-0.52]), late gastrointestinal (OR 0.31[0.10-0.93]), genitourinary (OR 0.31[0.09-1.01]) and vaginal toxicities (0% vs. 29.6%). Grade ≥ 3 toxicity was low in both groups (2D-BT: 8.2% acute, 13.3% late vs. 3D-IGABT: 6.3% acute, 4.4% late, NS). The five-year LRC, DC, FFS, CSS and OS for 3D-IGABT were 92.0%, 63.4%, 61.7%, 75.4% and 73.6%, compared to 87.3%, 71.8%, 63.7%, 76.3% and 70.8% for 2D-BT (NS).

CONCLUSIONS

3D-IGABT for the treatment of LACC is associated with a decrease in overall late gastrointestinal, genitourinary and vaginal toxicities. The disease control or survival outcomes were comparable to contemporary 3D-IGABT studies.

Long-Term Efficacy and Toxicity of Intensity-Modulated Radiotherapy in Bulky Cervical Cancer

Treatment of bulky cervical cancer is associated with both high adverse effects and local recurrence rates with traditional box method radiotherapy. Intensity-modulated radiotherapy (IMRT) has been adopted for the treatment of cervical cancer in order to deliver more precise radiation doses to the target region. We retrospectively enrolled a total of 98 patients with cervical cancer ≥4 cm who completed IMRT and point A-based brachytherapy treatment. The median follow-up time of the cohort was 6.84 years, with the 5-year OS and DFS being 66.33% and 75.12%, respectively. In addition, 7.14% of patients experienced local recurrence, 12.24% had distant recurrence, 6.12% had both local and distant recurrence, and 3.06% had persistent disease. In the univariate analysis, lymph node metastasis, higher creatinine levels, higher initial CA-125 and receiving chemotherapy other than cisplatin were all associated with a worse PFS. A tumor size ≥6 cm was associated with an increased incidence of higher grade of acute diarrhea. Grade 3 late radiation proctitis and cystitis developed in 11.22% and 13.27% of patients, respectively. The local recurrence rates and overall efficiencies were not inferior to other studies involving traditional pelvic external beam radiation therapy with concurrent chemotherapy. The safety and efficacy of IMRT for bulky cervical cancer were acceptable.

Image-Guided Versus Conventional Brachytherapy for Locally Advanced Cervical Cancer: Experience of Single Institution with the Same Practitioner and Time Period

PURPOSE

This study aimed to compare treatment outcomes and toxicity profile between imaged-guided brachytherapy (IGBT) versus conventional brachytherapy (CBT) performed by the same practitioner during the same time period.

MATERIALS AND METHODS

Medical records of 104 eligible patients who underwent brachytherapy for locally advanced cervical cancer were retrospectively reviewed. Fifty patients (48.1%) underwent IGBT, and 54 (51.9%) patients underwent CBT. All patients underwent concurrent chemoradiation with cisplatin. High-dose-rate intracavitary brachytherapy with dose prescription of 25-30 Gy in 4-6 fractions was performed for all patients. Late lower gastrointestinal (GI) and urinary toxicities occurred more than 3 months after the end of brachytherapy were included for comparative and dosimetric analyses.

RESULTS

The median follow-up period was 18.33 months (range, 3.25 to 38.43 months). There were no differences in oncologic outcomes between the two groups. The IGBT group had lower rate of actuarial grade ≥ 3 toxicity than the CBT group (2-year, 4.5% vs. 25.7%; p=0.030). Cumulative equieffective D2cc of sigmoid colon was significantly correlated with grade ≥ 2 lower GI toxicity (p=0.033), while equieffective D2cc of rectum (p=0.055) and bladder (p=0.069) showed marginal significance with corresponding grade ≥ 2 toxicities in the IGBT group. Half of grade ≥ 3 lower GI toxicities impacted GI tract above the rectum. Optimal thresholds of cumulative D2cc of sigmoid colon and rectum were 69.7 Gy and 70.8 Gy, respectively, for grade ≥ 2 lower GI toxicity.

CONCLUSION

IGBT showed superior toxicity profile to CBT. Evaluating the dose to the GI tract above rectum by IGBT might prevent some toxicities.

Metal artifact reduction in cervix brachytherapy with titanium applicators using dual-energy CT through virtual monoenergetic images and an iterative algorithm: A phantom study

PURPOSE

To evaluate an iterative metal-artifact reduction (iMAR) algorithm, dual-energy CT (DECT) through virtual monoenergetic images (VMI), and a combination of iMAR and DECT for reducing metal artifact severity (AS) induced by Fletcher titanium applicators used in cervix brachytherapy, the efficacy of which are hitherto unreported.

METHODS AND MATERIALS

120 kV_p single-energy CT (SECT) (Siemens) of BEBIG tandem applicators, varying in shape (straight or curved) and diameter (3.5 mm or 5 mm) in a custom-made water-filled phantom, and their DECT images obtained from extrapolation of 80 kVp and 140 kVp, were reconstructed using four methods: DECT through VMI±iMAR, and SECT±iMAR. The DECT images were reconstructed monoenergetically at 70, 150, and 190 keV. AS was evaluated using measured values and statistical analysis.

RESULTS

iMAR, DECT, and combined DECT and iMAR reduced AS (p < 0.05). DECT had a lower AS than SECT, even without iMAR (p < 0.025). SECT+iMAR was more effective than DECT-iMAR with VMI at 70 and 190 keV (p < 0.05), whereas showing no statistically significant difference at 150 keV. With DECT and iMAR combined, AS was reduced more effectively compared to the SECT+iMAR or DECT alone. It also reduced the mean interobserver uncertainty by 0.2 mm.

CONCLUSIONS

These findings indicate that iMAR reduces the AS caused by Fletcher titanium applicators for both SECT and DECT, a combination of iMAR and DECT is superior to either strategy alone, and at low energies, DECT+iMAR also produces similar artifact reduction. These practical strategies promise more accurate source-position and structure definitions in CT-based gynecological brachytherapy treatment planning.

Comparative Analysis of 60Co and 192Ir Sources in High Dose Rate Brachytherapy for Cervical Cancer

High-dose-rate (HDR) brachytherapy (BT) is an essential treatment for cervical cancer, one of the most prevalent gynecological malignant tumors. In HDR BT, high radiation doses can be delivered to the tumor target with the minimum radiation doses to organs at risk. Despite the wide use of the small HDR 192Ir source, as the technique has improved, the HDR 60Co source, which has the same miniaturized geometry, has also been produced and put into clinical practice. Compared with 192Ir (74 days), 60Co has a longer half-life (5.3 years), which gives it a great economic advantage for developing nations. The aim of the study was to compare 60Co and 192Ir sources for HDR BT in terms of both dosimetry and clinical treatment. The results of reports published on the use of HDR BT for cervical cancer over the past few years as well as our own research show that this treatment is safe and it is feasible to use 60Co as an alternative source.

Point-A vs. volume-based brachytherapy for the treatment of cervix cancer: A meta-analysis

BACKGROUND & PURPOSE

To report disease-free survival (DFS) for volume-based and point-A based brachytherapy (BT) in locally advanced cervical cancer.

MATERIALS & METHODS

We conducted a meta-analysis of studies assessing the effects of point-A and volume-based brachytherapy on 3-year DFS. Studies including stage I-IVA cervical cancer patients were included if standard treatment of concomitant chemo-radiotherapy and high-dose- or pulsed dose rate BT was delivered. The primary outcome was 3-year DFS, and secondary outcomes were 3-year local control (LC), 3-year overall survival (OS) and late toxicity. A random-effects subgroup meta-analysis was done.

RESULTS

In total, 5499 studies were screened, of which 24 studies with 5488 patients were eligible. There was significant heterogeneity among point-A studies (1538 patients) (I² = 82%, p < 0.05) relative to volume-based studies (3950 patients) (I² = 58, p = 0.01). The 3-year DFS for point-A and volume-based studies were 67% (95% CI 60%-73%) and 79% (95% CI 76%-82%) respectively (p = 0.001). Three-year LC for point-A and volume-based studies were 86% (95% CI 81%-90%) and 92% (91%-94%) respectively (p = 0.01). The difference in 3-year OS (72% vs. 79%, p = 0.12) was not statistically significant. The proportion of prospectively enrolled patients was 23% for point-A studies and 33% for volume-based studies. There was no difference in late grade 3 or higher gastrointestinal (3% vs. 4%, p = 0.76) genitourinary toxicities (3% vs. 3% p = 0.45) between the two groups.

CONCLUSION

Volume-based BT results in superior 3-year DFS and 3-year LC. In the absence of randomized trials, this meta-analysis provides the best evidence regarding transition to 3D planning.

Optimizing the IPSA Conditions to Improve the Treatment Plan Quality in Brachytherapy for Cervical Cancer

Recent prevalent use of three-dimensional image-guided brachytherapy (3D brachytherapy) has dramatically improved the treatment outcomes of cervical cancer. Inverse planning simulated annealing (IPSA) is one of the commonly used algorithms in 3D brachytherapy, but different conditions may affect the treatment plan quality. In this study, we compared HRCTV (high-risk clinical target volume) D90 (dose prescription) and HRCTV D95 D2cc (dose received by 2.0cc) of the rectum, bladder, and sigmoid in 30 patients with cervical cancer under four IPSA conditions. The HRCTV D90 (mean ± SD cGy) was 607.32 ± 37.86, 599.01 ± 23.62, 598.67 ± 13.07, and 596.45 ± 10.94 in four groups, respectively. The HRCTV D95 was 558.19 ± 38.51, 558.17 ± 25.72, 557.03 ± 16.12, and 555.26 ± 12.78, respectively. The sigmoid D2cc was 282.96 ± 44.84, 273.14 ± 60.69, 268.94 ± 62.32, and 292.69 ± 52.44. HRCTV D90, HRCTV D95, and sigmoid D2cc were not statistically different among the four groups (p > 0.05). However, the target fitness in group one, especially at the cervix, was poor. The rectum D2cc was 351.49 ± 32.90, 361.49 ± 28.09, 370.82 ± 24.44, and 375.33 ± 30.90. The rectum D2cc in group one was the lower than that in group three and group four ( $p<0.05$ ). The bladder D2cc was 423.59 ± 31.39, 380.75 ± 37.25, 383.27 ± 32.55, and 385.22 ± 25.79. The bladder D2cc in group one was higher than the other groups ( $p<0.05$ ). The maximum rectum limit dose (400cGy) is lower than the bladder (500cGy), and HRCTV is a whole in the IPSA algorithm; these result in the insufficiency or even absence of cervix dose that first need to meet in clinics. In conclusion, IPSA condition optimization can improve the quality of treatment plan in 3D brachytherapy and make it closer to clinical practice.

Advances in Radiation Oncology for the Treatment of Cervical Cancer

Background: Over the past two decades, there has been significant advancement in the management of cervical cancer, particularly in the domain of definitive chemoradiotherapy for locally advanced cervical cancer (LACC). Indeed, radiation treatment paradigms have shifted from a two-dimensional (2D) approach solely based on anatomical bony landmarks, to an image-guided three-dimensional (3D) approach, with the goal of delivering doses more precisely to clinical targets with an increased sparing of organs-at-risk. Methods: This is a narrative review on the advances in radiation technologies for the treatment of cervical cancer. Using the PubMed database, we identified articles published in English up until November 18, 2021 on the treatment of LACC with external beam radiotherapy (EBRT) and brachytherapy. A search of the Clinicaltrials.gov and Clinicaltrialsregister.eu retrieved information on ongoing clinical trials on the topic of combined immunotherapy and radiotherapy in cervical cancer. Results: We highlight the historical evolution from the use of 2D radiotherapy to 3D-conformal radiotherapy, and then intensity modulated radiotherapy (IMRT) for the delivery of EBRT. We also discuss advances in brachytherapy, notably the transition to 3D image-guided adaptive brachytherapy (3D-IGABT). In this context, we highlight large cohort studies that were recently constructed and have shown significant improvement in local control and treatment-related toxicities with 3D-IGABT. Finally, we discuss other advances in the field, notably the use of stereotactic body radiotherapy (SBRT) as a substitute to brachytherapy, and the addition of immunotherapy to chemoradiation. Conclusions: The use of IG-IMRT and 3D-IGABT have considerably improved treatment outcomes and toxicity profiles for patients with LACC, and are now considered the gold standard in many countries. The use of SBRT boost as a replacement for brachytherapy has been associated with increased toxicity and decreased efficacy and should be used with caution in the context of clinical trials. New experimental approaches include the addition of immunotherapy to chemoradiation regimens.

Surgery followed by concurrent radiochemotherapy as treatment for patients with locally recurrent cervical cancer

Background

No standard treatment exists for patients with recurrent cervical cancer. This study aimed to determine the role of surgery, followed by concurrent radiochemotherapy, as a treatment for recurrent pelvic cervical cancer without previous radiotherapy.

Methods

The current study identified patients diagnosed with vaginal and/or pelvic sidewall recurrent cervical cancer after primary surgery without radiotherapy in Zhejiang Cancer Hospital from May 2012 to November 2016. These enrolled patients underwent surgery, followed by concurrent radiochemotherapy and data were analyzed.

Results

This study enrolled 27 patients, including 11 with central (vaginal) and 16 with noncentral (pelvic sidewall with or without vaginal) recurrences. The median follow-up time after recurrence was 64 months (range, 5–110 months). All patients underwent surgery to resect the tumor as completely as possible and pelvic external beam radiotherapy (EBRT) with a median equivalent dose in 2 Gy fractions (EQD2) of 45.1 Gy (range, 44.3–47.8 Gy) with concurrent weekly cisplatin chemotherapy. The median EQD2 dose for the tumor bed/residual tumor was 51 Gy (range, 44.3–73.4 Gy), including 18 patients with a boost dose by EBRT or vaginal brachytherapy (VBT). The 5-year overall survival (OS) rates were 77.1% (central) and 65.7% (noncentral) without a statistically significant difference (P=0.246). Progression-free survival (PFS) rates were 81.8% (central) and 34.4% (noncentral), respectively, with a statistically significant difference (P=0.047). Three patients with noncentral recurrence experienced grade ≥3 complications associated with surgery.

Conclusions

Surgery followed by concurrent radiochemotherapy was a feasible and effective treatment with acceptable complications for locally recurrent cervical cancer, which markedly improved the survival of pelvic sidewall recurrence.

Combined Interstitial and Intracavitary High-Dose Rate Brachytherapy of Cervical Cancer

High-dose-rate brachytherapy by remote afterloading is now performed under three-dimensional image guidance by CT or MRI. Three-dimensional image-guided brachytherapy in cervical cancer disclosed that the traditional intracavitary brachytherapy by Manchester method cannot deliver an adequate dose to the large tumor with resulting local recurrence. To improve the local control rate, combined interstitial and intracavitary (hybrid) brachytherapy can increase the dose to the large parametrial involvement without increasing the dose to the rectum and bladder. Whether hybrid brachytherapy can be performed safely on a multi-institutional basis remains to be studied. From 2015, phase I/II study of hybrid brachytherapy was launched in Japan, and it was revealed that hybrid brachytherapy can be performed safely and with a high quality of radiation dose distribution in a multi-institutional study. In Japan, the number of patients undergoing hybrid brachytherapy in cervical cancer is rapidly rising. Education and clinical trial are very important to establish hybrid brachytherapy in the management of cervical cancer.

Effects of 3D image-guided brachytherapy compared to 2D conventional brachytherapy on clinical outcomes in patients with cervical cancer: A systematic review and meta-analyses

PURPOSE

To assess the effects of three-dimensional image-guided brachytherapy (3D BT) compared to bi-dimensional BT (2D BT) on clinical outcomes in patients with cervical cancer.

METHODS AND MATERIALS

We searched PubMed/MEDLINE, EMBASE, Scopus, CENTRAL, Web of Science, and LILACS for studies assessing the effects of 3D BT versus 2D BT on clinical outcomes. Two reviewers independently screened retrieved citations, extracted data and assessed risk of bias from eligible studies. Hazard ratios (HR) were calculated from Kaplan-Meier curves considering the number of events, their timing and the followup of censored patients. We conducted meta-analyses of HR using the inverse-variance random-effects method. Risk Difference (RD) for toxicities were pooled using the Mantel-Haenszel random-effects method. We used the GRADE system to rate the certainty of evidence.

RESULTS

Twenty observational studies involving 4287 patients were included. The meta-analyses assessing the effect of 3D BT versus 2D BT on overall survival resulted in a HR of 0.78 (95%CI 0.62-0.98), HR of 0.75 (95%CI 0.62-0.90) for pelvic disease-free survival, HR of 0.93 (95%CI 0.81-1.06) for metastatic disease-free survival, and HR of 0.77 (95%CI 0.59-0.99) for local control. Grade 3-4 global and gastrointestinal toxicities were, respectively, 9% lower (95%CI 6% to 11%) and 5% lower (95%CI 2% to 8%) in patients receiving 3D BT versus 2D BT. Certainty of evidence was very low for all assessed outcomes.

CONCLUSIONS

Our study may suggest a benefit of 3D BT over conventional 2D BT on important clinical outcomes.

Radiotherapy and Its Intersections with Surgery in the Management of Localized Gynecological Malignancies: A Comprehensive Overview for Clinicians

Surgery, including minimally invasive surgery, and radiotherapy are key modalities in the treatment of gynecological malignancies. The aim of this review is to offer the multidisciplinary care team a comprehensive summary of the intersections of surgery and radiotherapy in the local treatment of gynecological malignancies. Recent advances in radiotherapy are highlighted. Relevant publications were identified through a review of the published literature. Ovarian, endometrial, cervical, vaginal, and vulvar cancer were included in the search. Current guidelines are summarized. The role of radiotherapy in adjuvant as well as definitive treatment of these entities is synthesized and put into context with surgery, focusing on survival and quality of life. Although these outcomes have improved recently, further research must be focused on the number of life years lost, and the potential morbidity encountered by patients.

Vaginal Fistulas of the Bladder and Small Bowel After Two-Dimensional Intracavitary Brachytherapy in a Patient With Cervical Cancer

Image-guided brachytherapy (IGBT) is commonly used for patients with cervical cancer, but two-dimensional intracavitary brachytherapy (2D-ICBT) is also still utilized for certain patients. We report a patient with cervical cancer who developed vaginal fistulas of the bladder and small bowel after chemoradiotherapy with 2D-ICBT. A 61-year-old woman with stage IIB cervical cancer underwent a combination of external beam radiotherapy (EBRT) at a dose of 50.4 Gy in 28 fractions and 2D-ICBT at a dose of 22 Gy in four fractions. As packs were well inserted around the uterus in all fractions of 2D-ICBT, the doses to the surrounding organs at risk (OAR) could be likely to be kept at low levels. She developed a huge fistula between the vagina and bladder approximately 2.5 years after radiotherapy (RT). She also developed a fistula between the vagina and small bowel approximately seven years after RT and underwent bypass from the small bowel to the transverse colon. The OAR were delineated using computed tomography for EBRT planning, and the cumulative dose of 2D-ICBT plus EBRT was evaluated as the source of toxicity. The cumulative dose converted to the equivalent dose in 2-Gy fractions (EQD2) was calculated using the linear-quadratic model with α/β = 3 for the OAR. The cumulative EQD2 values of the minimum dose to the most irradiated 2 cc (D2cc) of the bladder and small bowel were 90.2 Gy and 79.5 Gy, respectively. These values exceeded the upper limits of the dosimetric criteria of the OAR, suggesting an association with both vaginal fistulas. As the adoption of IGBT is too slow in some countries, it is noteworthy that a reduced bladder volume may result in a significant increase in the dose to the small bowel and bladder in 2D-ICBT.