Preliminary analysis of chronic gastrointestinal toxicity in gynecology patients treated with intensity-modulated whole pelvic radiation therapy.
OBJECTIVE
To provide a preliminary analysis of chronic gastrointestinal (GI) toxicity in gynecology patients treated with intensity-modulated whole pelvic radiation therapy (IM-WPRT).


METHODS
Between February 2000 and August 2001, 36 gynecology patients received IM-WPRT. All patients underwent a contrast-enhanced computed tomography scan, and a clinical target volume (CTV) was contoured consisting of the upper vagina, parametria, uterus (if present), and presacral and pelvic lymph node regions. The CTV was expanded by 1 cm to create a planning target volume (PTV). Seven or 9-field IM-WPRT plans were generated. IM-WPRT plans were highly conformal, providing excellent coverage of the PTV and considerable sparing of normal tissues, including the small bowel and rectum. Chronic GI toxicity was scored: 0 (no symptoms), 1 (mild symptoms, no medications required), 2 (moderate symptoms, medications required), and 3 (severe symptoms, hospitalization, surgery required). Chronic GI toxicity in 30 gynecology patients treated with conventional WPRT patients before the implementation of IM-WPRT was also evaluated. Median follow-up in the IM-WPRT and WPRT groups were 19.6 and 30.2 months, respectively.


RESULTS
The IM-WPRT and WPRT groups were well balanced in terms of most patient and treatment factors, including age, site, stage, chemotherapy, WPRT dose, and brachytherapy, except for a higher frequency of surgery (75 vs. 54%, p = 0.02) in the IM-WPRT group. Overall, IM-WPRT patients had a lower rate of chronic GI toxicity (11.1 vs. 50.0%, p = 0.001) than WPRT patients. The percentage of IM-WPRT patients with Grade 1, 2, and 3 toxicity were 8.3%, 2.8%, and 0%, respectively. Corresponding percentages in the WPRT group were 30.0%, 16.7%, and 3.3%, respectively. The only other factor correlated with chronic GI toxicity was age (p = 0.02). On multivariate (logistic regression) analysis controlling for age and other clinical factors, IM-WPRT retained its statistical significance (p = 0.01; odds ratio 0.16; 95% confidence interval 0.04, 0.67)


CONCLUSIONS
Our results suggest that IM-WPRT is associated with less chronic GI toxicity than conventional WPRT in patients with gynecologic malignancies. However, longer follow-up and more patients are clearly needed to ascertain whether the benefits of IM-WPRT treatment seen here translate into true long-term reductions in chronic GI toxicity.
Mundt
Arno J
AJ
Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, IL 60637, USA. mundt@rover.uchicago.edu
Mell
Loren K
LK
Roeske
John C
JC
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004064:Digestive System / Q000528:radiation effects*; D016889:Endometrial Neoplasms / Q000532:radiotherapy; D005260:Female; D005833:Genital Neoplasms, Female / Q000532:radiotherapy*; D006801:Humans; D008875:Middle Aged; D015999:Multivariate Analysis; D010388:Pelvis / Q000528:radiation effects; D011878:Radiotherapy / Q000009:adverse effects; D002583:Uterine Cervical Neoplasms / Q000532:radiotherapy