Is bone marrow sparing intensity modulated radiotherapy better than 3-dimensional conformal radiotherapy in reducing haematological toxicities during pelvic irradiation in locally advanced carcinoma cervix?: A prospective study

Abstract

Background: Our study was designed to evaluate acute toxicities and clinical outcomes in patients of locally advanced cervical cancer treated with 3‐Dimensional Conformal Radiotherapy (3DCRT), Non Bone marrow sparing Intensity modulated radiotherapy (NBMS IMRT) and Bone marrow sparing IMRT (BMS IMRT) techniques. Methods: 36 patients of squamous cell carcinoma of cervix with International Federation of Gynaecology and Obstetrics (FIGO) stage IB2‐IIIB were allotted into 3 study groups, 3DCRT, NBMS IMRT and BMS IMRT, based on a computer generated randomization table. All patients were treated with External beam radiotherapy (46Gy/ 23#/41/2weeks) and concurrent weekly cisplatin (40mg/m2) chemotherapy. Acute toxicity was graded according to Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. The primary endpoint was ≥grade 2 haematological toxicity (HT). The secondary endpoints were gastrointestinal (GI) toxicity (≥grade 2) and local control (LC) at the end of 1 year. Results: Of the 36 patients, 12 each were randomly allocated into the three study groups. 4 patients were of stage Ib, 26 were stage IIb and 6 were stage IIIb. Evaluation of doses to organs at risk across the three arms showed that IMRT significantly decreased the doses to bowel (p<0.01) and bone marrow (p<0.01) compared to the 3DCRT arm. Patients of 3DCRT arm experienced worse ≥grade 2 abdominal pain (p<0.009) and��grade 2 dermatitis (p<0.002) when compared to both IMRT groups. The median follow up time was 37 months. The LC at the end of one year and 3 years was 94.4% and 85.7%, respectively. The median overall survival and disease free survival was 37 months and 32 months, respectively, which was not statistically different between the study arms. Of the 36 patients, 4 patients have developed distant metastasis till date. Conclusions: Bone marrow sparing did not reduce the incidence of HT in cervical cancer patients. However, the use of IMRT showed a significant dosimetric and clinical benefit, with reduced incidence of GI toxicities. There was no difference in LC between the three arms.