Stereotactic Body Radiotherapy Boost Versus Simultaneous Integrated Boost to Pelvic Nodes Among Patients Receiving Radical Chemoradiation in Carcinoma Cervix

Arms (2)

1. type

   EXPERIMENTAL

   label

   Stereotactic Body Radiotherapy (SBRT) boost to involved pelvic lymph nodes (14 Gy in 2 fractions)

   description

   The experimental arm Stereotactic Body Radiotherapy (SBRT) boost regimen will consist of two fractions of 700 cGy each total of 14Gy in 2 fractions, delivered at 1st and 2nd week of the treatment.In the proposed protocol, the pelvic field dose will be delivered as 45 Gy in 25 fractions, while the nodal boost will be delivered as SBRT 14 Gy in 2 fractions, typically at the first and second weeks of treatment, subject to plan evaluation and organ-at-risk constraints. This sequencing is consistent with the concept of combining broad pelvic coverage with ablative focal escalation. Patients will be immobilized supine with an abdominopelvic thermoplastic shell, and simulation will be performed using contrast-enhanced planning CT with MRI and PET-CT fusion where available. Bladder and bowel preparation will be standardized before simulation and treatment to improve reproducibility and reduce interfraction variation.

   interventionNames

   1. Radiation: Stereotactic Body Radiotherapy Boost to Involved Pelvic Lymph Nodes

2. type

   ACTIVE_COMPARATOR

   label

   Conventional nodal boost by Simultaneous Integrated Boost (SIB)to involved pelvic lymph nodes)

   description

   Patients in the standard arm will receive conventional radical chemoradiation for locally advanced carcinoma cervix with pelvic external beam radiotherapy and concurrent weekly cisplatin, followed by brachytherapy. Pelvic radiotherapy will be delivered to a dose of 45 Gy in 25 fractions over 5 weeks, using IMRT/VMAT or fixed-field technique, with standard contouring of elective pelvic target volumes and gross disease. The nodal boost will be delivered as a conventional Simultaneous Integrated Boost (SIB) to the involved pelvic node(s) during the course of external beam radiotherapy. A total dose of 55 Gy or 57.5 Gy in 25 fractions, delivered in a simultaneous integrated manner according to nodal size, location, and institutional planning constraints. Treatment will be planned with appropriate image guidance, and organs at risk will be respected according to predefined dose constraints. Toxicity will be monitored during treatment and follow-up, and graded using CTCAE version 5.0.