title: Predictors of grade 3 or higher late bowel toxicity in patients undergoing pelvic radiation for cervical cancer: results from a prospective study.
abstract: OBJECTIVE
  The present study investigates relationship between dose-volume parameters and severe bowel toxicity after postoperative radiation treatment (PORT) for cervical cancer.
  
  
  METHODS
  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%.
authors: Department of Radiation Oncology, Advanced Centre for Treatment Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai, Maharashtra, India. Electronic address: schopra@actrec.gov.in.
authors: Supriya
authors: S
authors: Chopra
authors: Department of Radiation Oncology, Advanced Centre for Treatment Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai, Maharashtra, India.
authors: Tapas
authors: T
authors: Dora
authors: Department of Radiation Oncology, Tata Memorial Hospital, Tata Memorial Centre, Parel, Mumbai, Maharashtra, India.
authors: Anand N
authors: AN
authors: Chinnachamy
authors: Department of Radiation Oncology, Advanced Centre for Treatment Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai, Maharashtra, India.
authors: Biji
authors: B
authors: Thomas
authors: Epidemiology and Clinical Trials Unit, Advanced Centre for Treatment Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai, Maharashtra, India.
authors: Sadhna
authors: S
authors: Kannan
authors: Department of Radiation Oncology, Tata Memorial Hospital, Tata Memorial Centre, Parel, Mumbai, Maharashtra, India.
authors: Reena
authors: R
authors: Engineer
authors: Department of Radiation Oncology, Tata Memorial Hospital, Tata Memorial Centre, Parel, Mumbai, Maharashtra, India.
authors: Umesh
authors: U
authors: Mahantshetty
authors: Department of Radiation Oncology, Advanced Centre for Treatment Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai, Maharashtra, India.
authors: Reena
authors: R
authors: Phurailatpam
authors: Department of Radiation Oncology, Advanced Centre for Treatment Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai, Maharashtra, India.
authors: Siji N
authors: SN
authors: Paul
authors: Department of Radiation Oncology, Tata Memorial Hospital, Tata Memorial Centre, Parel, Mumbai, Maharashtra, India.
authors: Shyam Kishore
authors: SK
authors: Shrivastava
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D059248:Chemoradiotherapy / Q000379:methods; D005260:Female; D006801:Humans; D007420:Intestine, Large / Q000528:radiation effects*; D007421:Intestine, Small / Q000528:radiation effects*; D008875:Middle Aged; D058958:Organs at Risk / Q000528:radiation effects*; D010388:Pelvis; D011182:Postoperative Care; D011446:Prospective Studies; D012372:ROC Curve; D011832:Radiation Injuries / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects / Q000379:methods; D020266:Radiotherapy, Conformal / Q000009:adverse effects / Q000379:methods; D061089:Radiotherapy, Image-Guided / Q000009:adverse effects / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects / Q000379:methods; D002583:Uterine Cervical Neoplasms / Q000188:drug therapy / Q000532:radiotherapy* / Q000601:surgery