Indian Data on the Response of Positive Pelvic Lymph Nodes in Carcinoma Cervix Patients Treated with Simultaneous Integrated Boost Using Volumetric Modulated Arc Radiation Therapy

Abstract

Background The percentage of pelvic lymph node (LN) positivity in cervical cancer patients varies from 19% in early stages to 68% in advanced cases. Thirty-three percent of patients will develop recurrence within 2 years following therapy, and 5-year relative survival for patients with affected regional LNs is 57%. Hence, pelvic LNs need to be included in the definitive plan of radiation treatment for better disease control and longer survival. With conventional radiation therapy, dose escalation was not possible because of small bowel constraints. With higher conformity of intensity-modulated radiotherapy technique, doses to pelvic and abdominal organs can be minimized. The added advantage of simultaneous integrated boost (SIB) is that high dose per fraction is delivered to the gross disease and low dose to the microscopic disease, thereby reducing the total treatment time and improving the therapeutic ratio. Materials and Methods Forty-one patients presenting to the Department of Radiation Oncology, between January 2016 and June 2017, with newly biopsy-proven carcinoma cervix Stage IB to IVA were enrolled in the study, and all the investigations were performed. The radiation dose was delivered using volumetric modulated arc therapy plan according to the dose of 5,000 cGy in 25 fractions to the whole pelvis and 5,500 cGy in 25 fractions to the involved nodes at 220 cGy per fraction using SIB along with weekly cisplatin at 40 mg/m2. After completion of external beam radiation, all the patients received three fractions of brachytherapy to a total dose of 21 Gy. Acute toxicities were assessed using Radiation Therapy Oncology Group criteria. At 3 months after completion of treatment, all the patients were followed up with diffusion-weighted magnetic resonance imaging of abdomen and pelvis to assess the response after 3 months. Results Of 41 carcinoma cervix patients with significantly positive LNs treated with SIB VMAT, 9.8% of the patients (4 patients) had residual nodal disease and 87.8% of the patients (36 patients) had a complete response, and 19.5% (8 patients) had residual disease of primary and 78% (32 patients) had a complete response at 3 months after completion of treatment with only grade I and grade II toxicities. Conclusion Treatment with SIB VMAT in carcinoma cervix patients with significant pelvic LNs shows a very good response with acceptable acute toxicities. But longer follow-up period is required to see if this response translates into better disease-free survival and overall survival.