R. Bhavana

Evaluation of brachytherapy applicators and their association with morbidity and local control in cervix cancer: An EMBRACE I analysis

To investigate the effects of brachytherapy (BT) applicator and implant type on morbidity and local control (LC) in locally advanced cervix cancer patients. 1071 patients treated with radiochemotherapy including MRI-guided BT using tandem&ring (T&R) or tandem&ovoids (T&O) from 19 EMBRACE-I centers were analyzed. Intracavitary (IC) or intracavitary/interstitial (IC/IS) implants were used. Centers came from different brachytherapy traditions and followed their institutional dose aims and planning strategies. LC and physician-assessed morbidity (median follow-up 48 months) was compared between applicator/implant types using Cox proportional hazard model adjusting for patient characteristics and treatment-related potential confounders. Moderate-to-severe (G ≥ 2) genito-urinary (cystitis/frequency/incontinence), gastro-intestinal (proctitis/bleeding/diarrhea) and vaginal (stenosis/mucositis) symptoms were analysed individually. Severe events (G ≥ 3) were pooled per organ. The T&O (n = 346) compared to T&R (n = 725) had a higher risk of morbidity, with HRs > 1.3 in 14/16 individual G ≥ 2 symptoms and in 3/4 G ≥ 3 pooled organ symptoms. Patients treated with IC/IS (n = 512) compared to IC (n = 559) were not at higher risk of G ≥ 2 symptoms, with HRs < 1 in 6/8 MVAs. Crude incidence of local failure was 7.3 % (25/343) for T&O and 6.6 % (47/712) for T&R. In this patient cohort, treated between 2008-2015, T&R and T&O demonstrated comparable LC. However, a higher risk of morbidity is reported for T&O. This increased risk was partly explained by hotspot doses, with factors such as irradiated volumes and organ irradiation length also contributing. Additionally, implant quality, dose planning aims and strategies, and morbidity reporting may have impacted the observed differences in morbidity. IC/IS applicators did not increase morbidity risk compared to IC applicators.

Point-Based Brachytherapy in Cervical Cancer With Limited Residual Disease: A Low- and Middle-Income Country Experience in the Era of Magnetic Resonance–Guided Adaptive Brachytherapy

PURPOSE To evaluate the clinical outcomes in patients with cervical cancer with limited residual disease at brachytherapy (BT) treated with point-based dose prescription. METHODS Patients with locally advanced squamous cell carcinoma of the cervix treated with computed tomography (CT)-based intracavitary BT were considered for analysis. Patients with good response to external beam radiotherapy and limited residual disease suitable for intracavitary BT alone were included. Postapplication CT scans were performed before each fraction and individual plans were made for each session. The dose per fraction was 9Gy high dose rate, prescribed to point-A. Two sessions were planned, 1 week apart. The organs at risk were contoured, and cumulative dose-volume histograms were computed. Local control, pelvic control, disease-free survival, and overall survival were evaluated and late toxicities were documented. RESULTS Four hundred ninety patients were included. Overall, 79.8% had International Federation of Gynecology and Obstetrics (FIGO) stage IB2 to IIB disease and 20.2% had stage III to IVA disease. Median dose at point A (EQD210Gy) was 74.4 Gy (interquartile range [IQR] 72.3-74.5 Gy) and median D2cc (EQD23Gy) for bladder, rectum, and sigmoid were 82.5 Gy (IQR, 65.5-90.8 Gy), 66.5 Gy (IQR, 60.7-75.7 Gy), and 54.1 Gy (IQR, 50.5-77.3 Gy), respectively. At a median follow-up of 62 (IQR, 33-87) months, the 5-year local and pelvic control rates were 90.1% and 88.3%, respectively. The 5-year disease-free survival was 80% and overall survival was 88%. Rates of grade 3-4 bladder and rectosigmoid toxicities were 6.93% and 4.08%, respectively. CONCLUSION In patients with limited residual disease at BT, point-based dose prescription with CT planning results in good local control and acceptable toxicity. In a resource-constrained setting, patients may be triaged to receive point-based BT or magnetic resonance imaging–guided adaptive BT depending on the extent of residual disease.