Treshita Dey

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.

Three-Dimensional Conformal Radiotherapy Versus Image-Guided Intensity Modulated External Beam Radiotherapy in Locally Advanced Cervical Cancer: A Phase III Randomized Control Study

The standard treatment of locally advanced cervical carcinoma is radical chemoradiation followed by brachytherapy which has improved survival. Hence, a major concern is our attempt to reduce the incidence of acute and late toxicities. IMRT has been shown to reduce toxicities. In this study, we have compared 3DCRT with IG-IMRT using patient-specific margins to evaluate tumor control as well as OAR-related toxicities. This was a single institution prospective phase III randomised control study including patients of squamous cell carcinoma of cervix (stage II-IIIB, FIGO 2009) without pelvic lymph node involvement. All patients were simulated using intermediate bladder filling protocol and those in the IG-IMRT arm, underwent additional scans with full and empty bladder to assess the range of internal motion and generate individualised ITV margin. EBRT dose of 46Gy/23#/4.5 weeks was delivered with weekly concurrent cisplatin followed by brachytherapy. All toxicities during EBRT and till 3 months post brachytherapy were considered acute toxicity. Post-treatment, patients were followed up every 2 months for first 2 years and then once every 6 months. Disease-related outcomes were assessed with clinical examination and symptom-directed imaging. Two hundred patients were screened for inclusion and of them, 89 patients in 3DCRT and 84 patients in IG-IMRT arms were considered for final analysis. The baseline characteristics were comparable in both arms, majority of patients in both arms having stage II disease. For OARs, all dosimetric parameters were significantly better in the IG-IMRT arm. Acute radiation induced toxicities (dermatitis, genito-urinary and gastrointestinal toxicities) were significantly less in the IG-IMRT arm. The local, pelvic, and distant control were comparable in both arms. Based on our experience, the use of IG-IMRT with patient-specific ITV margins results in reduction in acute OAR toxicities in patients without compromising on tumor control.