Multiple randomized controlled trials have established concurrent cisplatin-based chemoradiotherapy as the standard of care for locally advanced cervical cancer [3-8]. The addition of concurrent cisplatin to radiotherapy (RT) increases pelvic control, disease-free survival (DFS) and overall survival; however, 5-year DFS and overall survival are still only approximately 60% and 5-year pelvic failure is approximately 30%. Moreover, acute gastrointestinal (GI) and hematologic toxicity are increased. Approximately 30% of patients will experience acute grade ≥ 3 toxicity, predominantly GI and hematologic. Methods to reduce toxicity during chemoradiotherapy, particularly gastrointestinal and hematologic, could mitigate this toxicity and take advantage of the therapeutic benefits of intensive concurrent chemotherapy.
Intensity modulated radiation therapy (IMRT) is a modern RT technique that differs from conventional techniques in many ways. First, patients undergo computed tomography (CT) simulation so that customized target volumes can be defined 3-dimensionally. IMRT treatment planning involves multiple beam angles and uses computerized inverse treatment planning optimization algorithms to identify dose distributions and intensity patterns that conform dose to the target, reducing radiation dose to surrounding tissues. IMRT delivery is typically accomplished with the use of multileaf collimators, which involve small motorized leaflets (collimators) that move in and out of the beam path, modulating the dose intensity.
PET-guided Bone Marrow Sparing IMRT is designed to spare hematopoietically active subregions of the pelvic bone marrow using quantitative image segmentation. Previous studies indicate this approach can reduce toxicity and improve chemotherapy tolerance, which may improve outcomes and help optimized delivery of cytotoxic chemotherapy.