Dose-volume correlation of cumulative vaginal doses and late toxicity after adjuvant external radiation and brachytherapy for cervical cancer

Dose-response relationship between volume base dose and tumor local control in definitive radiotherapy for vaginal cancer

OBJECTIVE

This study aimed to establish the dose-response relationship between volume base dose and tumor local control for vaginal cancer, including primary vaginal cancer and recurrent gynecologic malignancies in the vagina.

MATERIALS AND METHODS

We identified studies that reported volume base dose and local control by searching the PubMed, the Web of Science, and the Cochrane Library Database through August 12, 2023. The regression analyses were performed using probit model between volume based dose versus clinical outcomes. Subgroup analyses were performed according to stratification: publication year, country, inclusion time of patients, patients with prior radiotherapy, age, primaries or recurrent, tumor size, concurrent chemoradiotherapy proportion, dose rate, image modality for planning, and interstitial proportion.

RESULTS

A total of 879 patients with vaginal cancer were identified from 18 studies. Among them, 293 cases were primary vaginal cancer, 573 cases were recurrent cancer in the vagina, and 13 cases were unknown. The probit model showed a significant relationship between the HR-CTV (or CTV) D90 versus the 2-year and 3-year local control, P values were 0.013 and 0.014, respectively. The D90 corresponding to probabilities of 90% 2-year local control were 79.0 GyEQD2,10 (95% CI: 75.3-96.6 GyEQD2,10).

CONCLUSIONS

A significant dependence of 2-year or 3-year local control on HR-CTV (or CTV) D90 was found. Our research findings encourage further validation of the dose-response relationship of radical radiotherapy for vaginal cancer through protocol based multicenter clinical trials.

Definitive radiation for advanced cervix cancer is not associated with vaginal shortening-a prospective vaginal length and dose correlation

PURPOSE

Prospectively measure change in vaginal length after definitive chemoradiation (C-EBRT) with Intracavitary Brachytherapy (ICBT) for locally advanced cervix cancer (LACC) and correlate with vaginal dose (VD).

MATERIALS AND METHODS

Twenty one female patients with LACC receiving C-EBRT and ICBT underwent serial vaginal length (VL) measurements. An initial measurement was made at the time of the first ICBT procedure and subsequently at 3 month intervals up to 1 year post radiation. The vagina was contoured as a 3-dimensional structure for each brachytherapy plan. The difference in VL before and at least 6 months after the last fraction of brachytherapy was considered as an indicator of toxicity.

RESULTS

The mean initial VL was 8.7 cm (6.5-12) with median value of 8.5 cm. The mean VL after 6 months was 8.6 cm (6.5-12) and VL change was not found to be statistically significant. The median values (interquartile ranges) for vaginal D0.1cc, D1cc, and D2cc were 129.2 Gy (99.6-252.2), 96.9 Gy (84.2-114.9), and 89.6 Gy (82.4-102.2), respectively. No significant correlation was found between vaginal length change and the dosimetric parameters calculated for all patients.

CONCLUSION

Definitive C-EBRT and ICBT did not significantly impact VL in this prospective cohort probably related to acceptable doses per ICRU constraints. Estimate of vaginal stenosis and sexual function was not performed in this cohort which is a limitation of this study and which we hope to study prospectively going forward.

Contouring of emerging organs-at-risk (OARS) of the female pelvis and interobserver variability: A study by the Italian association of radiotherapy and clinical oncology (AIRO)

Purpose

To provide straightforward instructions for daily practice in delineating emerging organs-at-risk (OARs) of the female pelvis and to discuss the interobserver variability in a two-step multicenter study.

Methods and materials

A contouring atlas with anatomical boundaries for each emerging OAR was realized by radiation oncologists and radiologists who are experts in pelvic imaging, as per their knowledge and clinical practice. These contours were identified as quality benchmarks for the analysis subsequently carried out. Radiation oncologists not involved in setting the custom-built contouring atlas and interested in the treatment of gynecological cancer were invited to participate in this 2-step trial. In the first step all participants were supplied with a selected clinical case of locally advanced cervical cancer and had to identify emerging OARs (Levator ani muscle; Puborectalis muscle; Internal anal sphincter; External anal sphincter; Bladder base and trigone; Bladder neck; Iliac Bone Marrow; Lower Pelvis Bone Marrow; Lumbosacral Bone Marrow) based on their own personal knowledge of pelvic anatomy and experience. The suggested OARs and the contouring process were then presented at a subsequent webinar meeting with a contouring laboratory. Finally, in the second step, after the webinar meeting, each participant who had joined the study but was not involved in setting the benchmark received the custom-built contouring atlas with anatomical boundaries and was requested to delineate again the OARs using the tool provided. The Dice Similarity Coefficient (DSC) and the Jaccard Similarity Coefficient (JSC) were used to evaluate the spatial overlap accuracy of the different volume delineations and compared with the benchmark; the Hausdorff distance (HD) and the mean distance to agreement (MDA) to explore the distance between contours. All the results were reported as sample mean and standard deviation (SD).

Results

Fifteen radiation oncologists from different Institutions joined the study. The participants had a high agreement degree for pelvic bones sub-structures delineation according to DICE (IBM: 0.9 ± 0.02; LPBM: 0.91 ± 0.01). A moderate degree according to DICE was showed for ovaries (Right: 0.61 ± 0.16, Left: 0.72 ± 0.05), vagina (0.575 ± 0.13), bladder sub-structures (0.515 ± 0.08) and EAS (0.605 ± 0.05), whereas a low degree for the other sub-structures of the anal-rectal sphincter complex (LAM: 0.345 ± 0.07, PRM: 0.41 ± 0.10, and IAS: 0.4 ± 0.07).

Conclusion

This study found a moderate to low level of agreement in the delineation of the female pelvis emerging OARs, with a high degree of variability among observers. The development of delineation tools should be encouraged to improve the routine contouring of these OARs and increase the quality and consistency of radiotherapy planning.

Brachytherapy impacts on sexual function: An integrative review of the literature focusing on cervical cancer

There is growing awareness of the importance of sexual health in the quality of life of cancer patients and survivors. Brachytherapy, a vital component for the curative treatment of cervical cancer, leads to both direct and indirect sequelae that result in vaginal and sexual morbidity. The emergence of 3D image-guided adaptive brachytherapy has led to a better understanding of dose-and-effect relationships for critical organs-at-risk and there are new recommendations for vaginal dose reporting in the ongoing EMBRACE II study. An understanding of the vagina as an organ-at-risk and its dose-and-effect relationships can help brachytherapists limit dose to the vagina and improve sexual morbidity. Brachytherapists play a critical role in the primary and secondary prevention of vaginal and sexual sequelae resulting from treatment. Through close surveillance and recognition of common symptoms, brachytherapists can intervene with effective strategies to prevent and treat vaginal and sexual symptoms. This review summarizes the current literature on dosimetric factors that may predict for vaginal morbidity. It will focus on quantitative and qualitative reports of brachytherapy-related vaginal toxicity and sexual dysfunction. Lastly, it will review the available evidence supporting clinical interventions to mitigate the development and progression of vaginal and sexual sequelae to improve functional quality post-treatment.

Vaginal 11-point and volumetric dose related to late vaginal complications in patients with cervical cancer treated with external beam radiotherapy and image-guided adaptive brachytherapy

OBJECTIVE

To investigate the vaginal 11-point and volumetric dose-toxicity relationships in definitive cervical cancer radiotherapy.

METHODS

A retrospective cohort study of patients with cervical cancer with a complete response of at least 12 months was performed. Additional per vaginal examinations and patient-scoring questionnaires on the date of patient enrolment were assessed for vaginal strictures. Retrospective dosimetric analysis of vaginal 11-point and volumetric doses was performed with descriptive and probit analyses to investigate dose-toxicity relationships.

RESULTS

Ninety-seven patients were included in the study, with a 20-month median follow-up. The incidence rate of grade 3 vaginal strictures was 22.7%. A comparison between patients with grade 1-3 vaginal strictures revealed significant differences in age, stage, initial tumour size, and vaginal involvement. PIBS + 2, PIBS, PIBS-2, D + 5, and D2cc were all significantly different among grade 1-3 vaginal strictures and showed significant probit coefficients. The lateral dose points were significantly higher in grade 2 strictures, but negative probit coefficients failed to establish causal inferences. Post-estimation analyses yielded effective doses (ED) for 15% and 20% probability of grade 3 vaginal strictures (ED15 and ED20) for PIBS + 2 at 57.4 and 111 Gy₃, respectively. PIBS-2 yielded an ED20 of 7 Gy₃. D + 5 yielded positive ED10, ED15, and ED20 values of 52.2, 66.6, and 78 Gy₃, respectively.

CONCLUSIONS

This study showed a significant relationship between age, tumour size, and lower-third vaginal involvement with the incidence of vaginal toxicity. The goal of a cumulative radiotherapy dose of ≤ 55 Gy₃ to PIBS + 2, ≤5 Gy₃ to PIBS-2, and ≤ 65 Gy₃ to D + 5 points may reduce the risk of grade 3 vaginal stenosis to less than 15-20%.

Vaginal dose-surface maps in cervical cancer brachytherapy: Methodology and preliminary results on correlation with morbidity

PURPOSE

The purpose of the study was to develop a methodology for vaginal dose-surface maps (DSMs) in patients with cervix cancer and to investigate dose-surface histogram metrics as predictors for vaginal stenosis (St) and mucositis (Muc).

METHODS AND MATERIALS

Thirty-one patients with locally advanced cervix cancer with no vaginal St/Muc (CTCAE-v3) G ≥ 2 at baseline were analyzed. Patients were divided in four morbidity groups: 15 with St/Muc G0/1, 6 with St G ≥ 2, 4 with St/Muc G ≥ 2, and 6 with Muc G ≥ 2. Patients received external beam radiotherapy and 4-fraction intracavitary/interstitial high-dose-rate brachytherapy using tandem and ovoids. DSMs were generated from inner/outer vaginal surfaces. DSMs of external beam radiotherapy and brachytherapy (Gy EQD2₃) were added based on a system of homologous points, to generate cumulative DSMs. Dose-surface histogram/dose-volume histogram parameters, location of high/intermediate-dose regions, rectovaginal reference point, vaginal lateral 5 mm point doses, and vagina/implant dimensions were investigated for St and Muc prediction. Average/difference DSMs and one-way analysis of variance were used to compare between groups.

RESULTS

Best predictors of stenosis were D_15-25cm2 and upper-vagina S_65-120Gy(%). Cutoffs of ∼90 Gy EQD2₃ for D_20cm2 and ∼80% for S_65Gy to top 3 cm inner vaginal surface suitably discriminated for stenosis. Spatial dose location on average/difference DSMs showed significantly higher doses (by > 20 Gy, p < 0.001) over longer parts of the dorsolateral vagina and higher rectovaginal reference point doses for any G ≥ 2 morbidity, over the whole circumference of the upper vagina for G ≥ 2 stenosis. Dose-volume histogram parameters were dependent on vaginal wall thickness. An increase of wall thickness from 2 to 4 mm resulted in an increase of D_2cm3 (D_4cm3) of 16% (32%).

CONCLUSIONS

A novel method was developed to generate vaginal DSMs and spatial-dose metrics. DSMs were found to correlate with vaginal stenosis. The findings of this study are promising and should be further validated on a larger patient cohort, treated with different applicators.

Quality of life in long term survivors of cervical cancer: A cross sectional study

Background

Quality of life (QOL) is an important parameter to evaluate and modify in patients treated for cervical cancer as long-term survival is excellent in early-stage and reasonably good in locally advanced stage compared to other solid cancers. The aim of the study was the cross sectional evaluation of the quality of life in survivors completing at least 3 years of follow-up after curative therapy for cervical cancer at a tertiary cancer institute.

Methods

All patients, following primary curative treatment with no evidence of recurrence and completing at least 3 years follow-up, were assessed for QOL using the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ)-30 and its cervical cancer module (Cx24). Patients were subdivided based on the modality of treatment. Analysis was done using Kruskal-Wallis and Mann-Whitney U test.

Results

One hundred seven patients were analyzed out of the 113 patients initially included. Treated patients showed good global QOL (mean value: 84.07) and functional scores (covering all domains). In the cervical cancer module, sexual activity, sexual enjoyment, and sexual function were low in the majority of the respondents. Chronic lymphedema, symptom experience, and sexual worry were significant across all the treatment arms.

Conclusion

Cervical cancer survivors have an overall good QOL. However, certain concerns related to the sexual quality of life, symptom experience, and chronic lymphedema need to be addressed appropriately.

Brachytherapy in India: Learning from the past and looking into the future

India has a longstanding tradition in the practice of brachytherapy and has actively contributed to the scientific literature by conducting prospective studies, clinical audits, developing innovative techniques, and performing randomized studies. Indian investigators have also contributed to international collaborative research, education, training programs along with guideline development for brachytherapy in cervix and head and neck cancers. The present article summarizes the key contributions to scientific literature, current infrastructure, skill set for brachytherapy, existing challenges, and strategy to further strengthen brachytherapy practice in the next decade.

Literature Review of Vaginal Stenosis and Dilator Use in Radiation Oncology

PURPOSE

Guidelines for the care of women undergoing pelvic radiation therapy (RT) recommend vaginal dilator therapy (VDT) to prevent radiation-induced vaginal stenosis (VS); however, no standard protocol exists. This review seeks to update our current state of knowledge concerning VS and VDT in radiation oncology.

METHODS AND MATERIALS

A comprehensive literature review (1972-2017) was conducted using search terms "vaginal stenosis," "radiation," and "vaginal dilator." Information was organized by key concepts including VS definition, time course, pathophysiology, risk factors, and interventions.

RESULTS

VS is a well-described consequence of pelvic RT, with early manifestations and late changes evolving over several years. Strong risk factors for VS include RT dose and volume of vagina irradiated. Resultant vaginal changes can interfere with sexual function and correlational studies support the use of preventive VDT. The complexity of factors that drive noncompliance with VDT is well recognized. There are no prospective data to guide optimal duration of VDT, and the consistency with which radiation oncologists monitor VS and manage its consequences is unknown.

CONCLUSIONS

This review provides information concerning VS definition, pathophysiology, and risk factors and identifies domains of VDT practice that are understudied. Prospective efforts to monitor and measure outcomes of patients who are prescribed VDT are needed to guide practice.

Literature Review of Vaginal Stenosis and Dilator Use in Radiation Oncology

PURPOSE

Guidelines for the care of women undergoing pelvic radiation therapy (RT) recommend vaginal dilator therapy (VDT) to prevent radiation-induced vaginal stenosis (VS); however, no standard protocol exists. This review seeks to update our current state of knowledge concerning VS and VDT in radiation oncology.

METHODS AND MATERIALS

A comprehensive literature review (1972-2017) was conducted using search terms "vaginal stenosis," "radiation," and "vaginal dilator." Information was organized by key concepts including VS definition, time course, pathophysiology, risk factors, and interventions.

RESULTS

VS is a well-described consequence of pelvic RT, with early manifestations and late changes evolving over several years. Strong risk factors for VS include RT dose and volume of vagina irradiated. Resultant vaginal changes can interfere with sexual function and correlational studies support the use of preventive VDT. The complexity of factors that drive noncompliance with VDT is well recognized. There are no prospective data to guide optimal duration of VDT, and the consistency with which radiation oncologists monitor VS and manage its consequences is unknown.

CONCLUSIONS

This review provides information concerning VS definition, pathophysiology, and risk factors and identifies domains of VDT practice that are understudied. Prospective efforts to monitor and measure outcomes of patients who are prescribed VDT are needed to guide practice.

Multivariate normal tissue complication probability modeling of vaginal late toxicity after brachytherapy for cervical cancer

PURPOSE

To explore the best variables combination for a predictive model of vaginal toxicity in cervical cancer patients undergoing brachytherapy (BT).

METHODS AND MATERIALS

Clinical and 3-dimensional dosimetric parameters were retrospectively extracted from an institutional database of consecutive patients undergoing intracavitary BT after external beam radiation therapy from 2006 to 2013 for a cervical cancer. A least absolute shrinkage and selection operator selection procedure in Cox's proportional hazards regression model was performed to select a set of relevant predictors for a multivariate normal tissue complication probability model of Grade ≥2 vaginal late toxicity. Outcomes reliability was internally assessed by bootstrap resampling method.

RESULTS

One hundred sixty-nine women were included in the present study with a median followup time of 3.8 years (interquartile range [IQR], 1.9-5.6 years). The 2 years and 5 years cumulative incidence rates of Grade ≥2 late vaginal toxicity were 19.9% and 27.5%, respectively. Among 31 metrics and six clinical factors extracted, the optimal model included two dosimetric variables: V70_Gy and D5_% (the percentage volume that received a dose greater or equal to 70 Gy and the minimum dose given to the hottest 5% volume, respectively). Area under the ROC curve at 2 and 5 years of followup were 0.85 and 0.91, respectively. Regarding internal validation, median area under the ROC curve of bootstrap predictions was 0.83 (IQR, 0.78-0.88) and 0.89 (IQR, 0.85-0.93) at 2 and 5 years of followup, respectively.

CONCLUSIONS

A multivariate normal tissue complication probability model for severe vaginal toxicity based on two dosimetric variables (V70_Gy and D5_%) provides reliable discrimination capability in a cohort of cervical cancer treated with external beam radiation therapy and BT.

Cancer cervix: Establishing an evidence-based strategy, an experience of a tertiary care centre in India

Carcinoma cervix is a common cancer among Indian women. Evidence based management is essential for best practice in treatment of carcinoma cervix for its effective control. The current imaging system like CT, MRI and PET CT scans have contributed in identifying the patients for optimal treatment and delivering treatment accurately. For stages IB2 to IV, concurrent chemoradiation is advocated with improvement in overall survival proven with randomized trials. Brachytherapy is an integral part in the radiation treatment. Imaged-guided brachytherapy using MRI is desirable, however less expensive imaging modalities such as CT and ultrasonography has been evaluated. In special situation such as for HIV positive patients and patients with neuroendocrine tumors have role of radiotherapy. For further improvement in control of cancer, it is required to integrate basic research to answer clinically relevant questions.