Predictors of severe gastrointestinal toxicity after external beam radiotherapy and interstitial brachytherapy for advanced or recurrent gynecologic malignancies.
OBJECTIVE
The aim of this retrospective review of patients with gynecologic malignancies treated with external beam radiotherapy (EBRT) and interstitial brachytherapy was to determine the rate of Grade > or =2 rectovaginal fistula and Grade > or =4 small bowel obstruction as defined by the National Cancer Institute Common Toxicity Criteria for Adverse Events, version 3.0.


METHODS
Thirty-six patients with primary and recurrent gynecologic cancers were treated with EBRT and interstitial brachytherapy. Median doses to tumor, bladder, and rectum were 75 Gy, 61 Gy, and 61 Gy, respectively. A univariate analysis was performed to identify variables that correlated with toxicity.


RESULTS
At median follow-up of 19 months, the 3-year risk of small bowel obstruction was 6%. Those patients with prior abdomino-pelvic surgery who received EBRT with antero-posterior fields had higher rates of obstruction than patients without prior abdomino-pelvic surgery or those who received EBRT with four fields (50% vs. 0%, p < 0.0001). The 3-year risk of rectovaginal fistula was 18% and was significantly higher in patients who received >76 Gy to the rectum compared with those who received < or =76 Gy (100% vs. 7%, p = 0.009).


CONCLUSIONS
Patients treated with EBRT and interstitial brachytherapy after abdomino-pelvic surgery should receive EBRT with four fields and the cumulative rectal dose should be < or =76 Gy.
Kasibhatla
Mohit
M
Department of Radiation Oncology, Dartmouth Hitchcock Medical Center, Hanover, NH 03756, USA. Mohit.S.Kasibhatla@Hitchcock.org
Clough
Robert W
RW
Montana
Gustavo S
GS
Oleson
James R
JR
Light
Kim
K
Steffey
Beverley A
BA
Jones
Ellen L
EL
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects / Q000379:methods; D002294:Carcinoma, Squamous Cell / Q000532:radiotherapy*; D016889:Endometrial Neoplasms / Q000532:radiotherapy; D005260:Female; D005833:Genital Neoplasms, Female / Q000532:radiotherapy*; D006801:Humans; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000532:radiotherapy*; D011832:Radiation Injuries; D012006:Rectovaginal Fistula / Q000209:etiology; D012007:Rectum / Q000528:radiation effects*; D012189:Retrospective Studies; D002583:Uterine Cervical Neoplasms / Q000532:radiotherapy; D014625:Vaginal Neoplasms / Q000532:radiotherapy