A randomized study for dosimetric assessment and clinical impact of bone marrow sparing intensity-modulated radiation therapy versus 3-dimensional conformal radiation therapy on hematological and gastrointestinal toxicities in cervical cancer.

Background: Cervical cancer requires multimodality therapy, resulting in acute toxicities. Intensity-modulated radiation therapy (IMRT) is postulated to spare bone marrow (BM) and bowel to reduce acute hematological and gastrointestinal (GI) toxicities of chemoradiotherapy.

Patients And Methods: This is a prospective randomized phase III study enrolling patients with Stage IB to IVA cervical carcinoma in two arms receiving either three-dimensional conformal radiotherapy (3DCRT) or IMRT from December 2017 to December 2019. The primary objective was to compare the hematologic toxicities (Grade 2 or more neutropenia as the primary factor) and the secondary objectives were to compare GI toxicities, and dosimetric analysis for volumes of BM, and bowel irradiated. SPSS version 20 was used for all statistical calculations.

Results: Eighty patients with histopathologically confirmed cervical cancer were randomized to receive IMRT or 3DCRT (40 in each arm). The median age of the patients was 56.5 (36-67) and 59.5 (37-68) years, respectively, in IMRT and 3DCRT arms. The median dose of external radiation was 50 Gy in 25 fractions, and of brachytherapy was 24 Gy in 3 fractions in both the arms. The incidence of grade ≥2 neutropenia was 42.5% and 15% in the 3DCRT and IMRT arms, respectively (P < 0.001). All patients received concurrent chemotherapy with cisplatin, with the median number of cycles being 5 (range 3-5) in both the arms. All five cycles of concurrent chemotherapy could be completed in 25 (62.5%) patients in the IMRT arm and 24 (60%) patients in the 3DCRT arm.

Conclusions: IMRT significantly reduces acute hematologic and GI toxicities compared with 3DCRT with a better dosimetry profile.