Radiation Duration in Women with Cervical Cancer Treated with Primary Chemoradiation: A Population-Based Analysis

Better late than never: Brachytherapy is more important than timing in treatment of locally advanced cervical cancer

PURPOSE

To evaluate the utilization of brachytherapy and duration of treatment on overall survival for locally advanced cervical cancer.

METHODS

The National Cancer Database (NCDB) was queried to identify stage II-IVA cervical cancer patients diagnosed in the United States between 2004 and 2015 who were treated with definitive chemoradiation therapy. We defined standard of care (SOC) treatment as receiving external beam radiation therapy (EBRT) and concurrent chemotherapy, brachytherapy (BT), and completing treatment within 8 weeks, and compared SOC treatment to non-SOC. The primary outcome was overall survival (OS). We also evaluated the effect of sociodemographic and clinical variables on receiving SOC.

RESULTS

We identified 10,172 women with locally advanced cervical cancer primarily treated with chemotherapy and concurrent EBRT of which 6047 (59.4%) patients received brachytherapy, and only 2978 (29.3%) completed treatment within 8 weeks (SOC). Receipt of SOC was associated with significantly improved overall survival (median OS 131.0 mos vs 95.5 mos, 78.1 mos, 49.2 mos; p < 0.0001). Furthemore, in patients whose treatment extended beyond 8 weeks, brachytherapy was still associated with an improved survival (median OS 95.5 vs 49.2 mos, p < 0.0001). More advanced stage, Non-Hispanic Black race, lower income, lack of insurance or government insurance, less education, and rural residence were associated with decreased likelihood of receiving SOC.

CONCLUSIONS

Completing standard of care concurrent chemoradiation therapy and brachytherapy in the recommended 8 weeks was associated with a superior overall survival. Patients who received brachytherapy boost show superior survival to patients receiving EBRT alone, regardless of treatment duration. Disparities in care for vulnerable populations highlight the challenges and importance of care coordination for patients with cervical cancer.

Comparison of Definitive Cervical Cancer Management With Chemotherapy and Radiation Between Two Centers With Variable Resources and Opportunities for Improved Treatment

PURPOSE

Cervical cancer remains a major health challenge in low- to middle-income countries. We present the experiences of two centers practicing in variable resource environments to determine predictors of improved radiochemotherapy treatment.

METHODS AND MATERIALS

This comparative review describes cervical cancer presentation and treatment with concurrent chemoradiotherapy with high-dose-rate brachytherapy between 2014 and 2017 at the National Radiotherapy Oncology and Nuclear Medicine Center (NRONMC) in Korle-Bu Teaching Hospital, Accra, Ghana, and Moffitt Cancer Center (MCC), Tampa, FL.

RESULTS

Median follow-up for this study was 16.9 months. NRONMC patients presented with predominantly stage III disease (42% v 16%; P = .002). MCC patients received para-aortic node irradiation (16%) and interstitial brachytherapy implants (19%). Median treatment duration was longer for NRONMC patients compared with MCC patients (59 v 52 days; P < .0001), and treatment duration ≥ 55 days predicted worse survival on multivariable analysis (MVA; P = .02). Stage ≥ III disease predicted poorer local control on MVA. There was a difference in local control among patients with stage III disease (58% v 91%; P = .03) but not in survival between MCC and NRONMC. No significant difference in local control was observed for stage IB, IIA, and IIB disease.

CONCLUSION

Although there were significant differences in disease presentation between the two centers, treatment outcomes were similar for patients with early-stage disease. Longer treatment duration and stage ≥ III disease predicted poor outcomes.

Radiation therapy for gynecologic malignancies during the COVID-19 pandemic: International expert consensus recommendations

OBJECTIVE

To develop expert consensus recommendations regarding radiation therapy for gynecologic malignancies during the COVID-19 pandemic.

METHODS

An international committee of ten experts in gynecologic radiation oncology convened to provide consensus recommendations for patients with gynecologic malignancies referred for radiation therapy. Treatment priority groups were established. A review of the relevant literature was performed and different clinical scenarios were categorized into three priority groups. For each stage and clinical scenario in cervical, endometrial, vulvar, vaginal and ovarian cancer, specific recommendations regarding dose, technique, and timing were provided by the panel.

RESULTS

Expert review and discussion generated consensus recommendations to guide radiation oncologists treating gynecologic malignancies during the COVID-19 pandemic. Priority scales for cervical, endometrial, vulvar, vaginal, and ovarian cancers are presented. Both radical and palliative treatments are discussed. Management of COVID-19 positive patients is considered. Hypofractionated radiation therapy should be used when feasible and recommendations regarding radiation dose, timing, and technique have been provided for external beam and brachytherapy treatments. Concurrent chemotherapy may be limited in some countries, and consideration of radiation alone is recommended.

CONCLUSIONS

The expert consensus recommendations provide guidance for delivering radiation therapy during the COVID-19 pandemic. Specific recommendations have been provided for common clinical scenarios encountered in gynecologic radiation oncology with a focus on strategies to reduce patient and staff exposure to COVID-19.

Data-Derived Treatment Duration Goal for Cervical Cancer: Should 8 Weeks Remain the Target in the Era of Concurrent Chemoradiation?

PURPOSE

Prior studies have demonstrated the importance of treatment duration (TD) in radiation therapy (RT) for cervical cancer, with an 8-week goal based primarily on RT alone. This study uses a contemporary cohort to estimate the time point by which completion of chemoradiation therapy is most critical.

PATIENTS AND METHODS

The National Cancer Database was queried for women with nonmetastatic cervical cancer diagnosed from 2004 to 2012 who underwent chemotherapy, external beam RT, and brachytherapy. Data-derived TD cut points for overall survival (OS) were computed by using recursive partitioning analysis with bootstrapped aggregation (bagging) and 10-fold cross-validation. Models were independently trained with 70% of the population and validated on 30% of the population by log-rank test with and without propensity matching. Multivariable Cox proportional hazards regression was performed for the entire cohort.

RESULTS

In all, 7,355 women were identified with a median TD of 57 days. Bagged recursive partitioning analysis converged to a mean cut point of 66.6 days (median, 64.5 days; interquartile range, 63.5 to 68.5 days). Cross-validation yielded a cut point of 63.3 days. Both cut points differentiated OS in validation. Younger age, recent diagnosis, geographic region, nongovernment insurance, shorter distance to treatment facility, metropolitan location, lower comorbidity, squamous cell carcinoma, lower stage, negative lymph nodes, and shorter TD were independently associated with longer OS. With adjustment, TD within the mean cut point (64.9 days; hazard ratio, 0.79; 95% CI, 0.73 to 0.87) and 56 days (hazard ratio, 0.87; 95% CI, 0.80 to 0.95) were associated with longer OS. Exploratory stratification suggested increasing OS detriment beyond 64 days.

CONCLUSION

Shorter chemoradiation TD in cervical cancer is associated with longer survival, and TD should be minimized as much as possible. The data-derived cut point was distributed around 64 days, with a continuous relationship between shorter TD and longer OS.

Racial disparities in brachytherapy administration and survival in women with locally advanced cervical cancer

OBJECTIVE

Black women have the highest incidence and mortality from cervical cancer in the United States. This study evaluated whether racial disparities in the receipt of brachytherapy (BT) for locally advanced cervical cancer mediate survival differences by race using the National Cancer Database.

METHODS

A retrospective cohort study was performed using 16,116 women with stage IB2-IVA cervical cancer treated from 2004 to 2014. Women who did not receive external beam radiation therapy, those with unknown survival data or stage, and those status post hysterectomy or pelvic exenteration were excluded. Multivariate logistic regression was performed to evaluate factors associated with BT use. Using a propensity score adjusted model with inverse probability treatment weighting, adjusted hazard ratios for overall survival were calculated, including an interaction term between BT and race.

RESULTS

Of 16,116 patients, 19.2% were black and 55.8% received BT. Black women were significantly less likely to receive BT (AOR 0.87, 95% confidence interval [CI] 0.79-0.96, p = 0.007) and had worse all-cause mortality (median survival 3.9 years [95% CI 3.6-4.6] versus 5.2 years [95% CI 4.9-5.5] for non-black women, p < 0.001). In the adjusted model, black patients had an increased risk of death compared to non-black patients (AHR 1.14, 95% CI 1.05-1.24; p = 0.002) among women who did not receive BT. However, there was no difference in survival by race when both groups received BT (AHR 1.04, 95% CI 0.95-1.13, p = 0.42; p-interaction = 0.005).

CONCLUSIONS

Black women with locally advanced cervical cancer are less likely to receive brachytherapy, which mediates survival differences by race. Improving access to brachytherapy may improve overall survival.

Radiobiological dose calculation parameters for cervix cancer brachytherapy: A systematic review

The GEC-ESTRO recommendation in cervical cancer treatment planning, including external beam radiotherapy and brachytherapy boosts, is to use radiobiological dose calculations. Such calculations utilize the linear-quadratic model to estimate the effect of multiple cellular response factors and dose delivery parameters. The radiobiological parameters utilized in these calculations are literature values estimated based on clinical and experimental results. However, the impact of the uncertainties associated with these parameters is often not fully appreciated. This review includes a summary of the radiobiological dose calculation (for both high-dose-rate and pulsed-dose-rate brachytherapy boost treatments) for cervical cancer and a compilation of the reported values of the associated parameters. As discrepancies exist between conventionally recommended and published values, equivalencies between current brachytherapy boosts may be imprecise and could create underappreciated uncertainties in the radiobiological dose calculations. This review highlights these uncertainties by calculating the radiobiological dose delivered by the brachytherapy boost when assuming different radiobiological parameter values (within the range reported by previous research). Furthermore, conventional treatment planning does not consider the effects of proliferation of the tumor over the treatment time, which can significantly decrease its radiobiological dose and can introduce an additional variance of over 7 Gy₁₀. Further investigation of uncertainties in parameter values and modifications of current dose models could improve the accuracy of radiobiological dose calculation.

Current Quality of Gynecologic Cancer Care in North America

Evaluating the quality of care received by gynecologic cancer patients in the real world is essential for excellent outcomes. The recent population-based literature looking at quality of care was reviewed for all gynecologic malignancies. Outcomes are generally highest when care is provided by high-volume providers in high-volume cancer centers. Provision of care according to clinical practice guidelines has also been demonstrated to improve outcomes in many situations. Disparities exist for marginalized groups in terms of the care they receive and subsequent outcomes. Health systems need to improve care for these populations.

Delays in definitive cervical cancer treatment: An analysis of disparities and overall survival impact

OBJECTIVE

Delays in time to treatment initiation (TTI) with definitive radiation therapy (RT) or chemotherapy and RT (CRT) for cervical cancer could lead to poorer outcomes. This study investigates disparities in TTI and the impact of TTI on overall survival (OS).

METHODS

Adult women with non-metastatic cervical squamous cell carcinoma diagnosed between 2004 and 2014, treated with definitive RT or CRT, and reported to the National Cancer Database were included. TTI was defined as days from diagnosis to start of RT or CRT. The impact of TTI on OS in patients treated with concurrent CRT which included brachytherapy was then assessed.

RESULTS

Overall, 14,924 patients were included (84.7% CRT, 15.3% RT). TTI was significantly longer for Non-Hispanic Black (NHB) (RR, 1.14; 95% CI, 1.11 to 1.18) and Hispanic women (RR, 1.19; 95% CI, 1.15 to 1.24) compared to Non-Hispanic White (NHW) women. Expected TTI (eTTI) for NHW, NHB, and Hispanic women were 38.1, 45.2, and 49.4days. eTTI rose from 36.2days in 2004 to 44.3days by 2014. Intensity-modulated radiation therapy (IMRT) was associated with increased eTTI of 46.5days versus 40.0days for non-IMRT. Longer TTI was not associated with inferior OS in patients treated with concurrent CRT.

CONCLUSIONS

Delays in starting RT/CRT for cervical cancer increased from 2004 to 2014. Delays disproportionately affect NHB and Hispanic women. However, increased TTI was not associated with increased mortality for women receiving CRT. Further study of TTI's impact on other endpoints is warranted to determine if TTI represents an important quality indicator.

American Brachytherapy Society: Brachytherapy treatment recommendations for locally advanced cervix cancer for low-income and middle-income countries

PURPOSE

Most cervix cancer cases occur in low-income and middle-income countries (LMIC), and outcomes are suboptimal, even for early stage disease. Brachytherapy plays a central role in the treatment paradigm, improving both local control and overall survival. The American Brachytherapy Society (ABS) aims to provide guidelines for brachytherapy delivery in resource-limited settings.

METHODS AND MATERIALS

A panel of clinicians and physicists with expertise in brachytherapy administration in LMIC was convened. A survey was developed to identify practice patterns at the authors' institutions and was also extended to participants of the Cervix Cancer Research Network. The scientific literature was reviewed to identify consensus papers or review articles with a focus on treatment of locally advanced, unresected cervical cancer in LMIC.

RESULTS

Of the 40 participants invited to respond to the survey, 32 responded (response rate 80%). Participants were practicing in 14 different countries including both high-income (China, Singapore, Taiwan, United Kingdom, and United States) and low-income or middle-income countries (Bangladesh, Botswana, Brazil, India, Malaysia, Pakistan, Philippines, Thailand, and Vietnam). Recommendations for modifications to existing ABS guidelines were reviewed by the panel members and are highlighted in this article.

CONCLUSIONS

Recommendations for treatment of locally advanced, unresectable cervical cancer in LMIC are presented. The guidelines comment on staging, external beam radiotherapy, use of concurrent chemotherapy, overall treatment duration, use of anesthesia, applicator choice and placement verification, brachytherapy treatment planning including dose and prescription point, recommended reporting and documentation, physics support, and follow-up.