Predictors of Grade 3 or Higher Late Bowel Toxicity in Patients Undergoing Pelvic Radiation for Cervical Cancer: Results From a Prospective Study

• Published in: International journal of radiation oncology, biology, physics Vol. 88; no. 3; pp. 630 - 635
• Main Authors: Chopra, Supriya, MD, Dora, Tapas, MD, Chinnachamy, Anand.N., MD, Thomas, Biji, BSc, Kannan, Sadhna, MSc, Engineer, Reena, DNB, Mahantshetty, Umesh, MD, Phurailatpam, Reena, DRP, Paul, Siji N., DRP, Shrivastava, Shyam Kishore, MD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.03.2014
• Subjects: Adult; Aged; Analysis of Variance; Chemoradiotherapy - methods; CHEMOTHERAPY; Female; Hematology, Oncology and Palliative Medicine; Humans; Intestine, Large - radiation effects; Intestine, Small - radiation effects; Middle Aged; MULTIVARIATE ANALYSIS; NEOPLASMS; Organs at Risk - radiation effects; PATIENTS; Pelvis; Postoperative Care; Prospective Studies; Radiation Injuries - etiology; Radiation Injuries - pathology; Radiation Injuries - prevention & control; Radiology; RADIOLOGY AND NUCLEAR MEDICINE; RADIOTHERAPY; Radiotherapy Dosage; Radiotherapy, Adjuvant - adverse effects; Radiotherapy, Adjuvant - methods; Radiotherapy, Conformal - adverse effects; Radiotherapy, Conformal - methods; Radiotherapy, Image-Guided - adverse effects; Radiotherapy, Image-Guided - methods; Radiotherapy, Intensity-Modulated - adverse effects; Radiotherapy, Intensity-Modulated - methods; ROC Curve; TOXICITY; Uterine Cervical Neoplasms - drug therapy; Uterine Cervical Neoplasms - radiotherapy; Uterine Cervical Neoplasms - surgery
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/j.ijrobp.2013.11.214

Purpose The present study investigates relationship between dose–volume parameters and severe bowel toxicity after postoperative radiation treatment (PORT) for cervical cancer. Methods and Materials From June 2010 to December 2012, a total of 71 patients undergoing PORT were included. Small bowel (SB) and large bowel (LB) loops were contoured 2 cm above the target volume. The volume of SB and LB that received 15 Gy, 30 Gy, and 40 Gy was calculated (V15 SB, V15 LB, V30 SB, V30 LB, V40 SB, V 40 LB). On follow-up, bowel toxicity was scored using Common Terminology Criteria for Adverse Events (CTCAE), version 3.0. A reciever operating characteristic (ROC) curve identified volume thresholds that predicted for grade 3 or higher toxicity with highest specificity. All data was dichotomized across these identified cut-off values. Univariate and multivariate analysis was performed using SPSS, version 15. Results The median patient age was 47 years (range, 35-65 years). Of the 71 patients, 46 received image-guided intensity modulated radiation therapy, and 25 received conformal radiation (50 Gy in 25 fractions for 5 weeks). Overall, 63 of 71 patients received concurrent chemotherapy. On a median follow-up of 18 months (range, 8-29 months), grade 2 or higher bowel toxicity was seen in 22 of 71 patients (30.9%) and grade 3 or higher bowel toxicity was seen in 9 patients (12.6%). On univariate analysis, V15 SB <275 cc ( P =.01), V30 SB <190 cc ( P =.02), V40 SB <150 cc ( P =.01), and V15 LB <250 cc ( P =.03), and V40 LB <90 cc ( P =.04) predicted for absence of grade 3 or higher toxicity. No other patient- or treatment-related factors were statistically significant. On multivariate analysis, only V15 SB ( P =.002) and V15 LB ( P =.03) were statistically significant. Conclusions V 15 Gy SB and LB are independent predictors of late grade 3 or higher toxicity. Restricting V15 SB and V15 LB to <275 cc and <250 cc can reduce grade 3 or higher toxicity to less than 5%.