Initial clinical experience with intensity-modulated whole-pelvis radiation therapy in women with gynecologic malignancies

Abstract

Objective: Our goal in this article to describe our initial experience with intensity-modulated whole-pelvis radiation therapy (IM-WPRT) in gynecologic malignancies.

Methods: Between February and August 2000, 15 women with cervical (9) or endometrial (6) cancer received IM-WPRT. All patients received a treatment planning computed tomography (CT) scan. On each scan, the target volume (upper vagina, parametrial tissues, presacral region, uterus, and regional lymph nodes) and normal tissues (small bowel, bladder, and rectum) were identified. Using commercially available software, an IM-WPRT plan was generated for each patient. The goal was to provide coverage of the target with the prescription dose (45 Gy) while minimizing the volume of small bowel, bladder, and rectum irradiated. Acute gastrointestinal (GI) and genitourinary (GU) toxic effects in these women were compared with those seen in 25 patients treated with conventional WPRT.

Results: IM-WPRT plans provided excellent coverage of the target structures in all patients and were highly conformal, providing considerable sparing of the bladder, rectum, and small bowel. Treatment was well tolerated, with grade 0-1 GI and GU toxicity in 46 and 93% of patients, respectively. IM-WPRT patients had a lower rate of grade 2 GI toxicity (53.4% vs 96%, P = 0.001) than those treated with conventional WPRT. Moreover, the percentage of women requiring no or only infrequent antidiarrheal medications was lower in the IM-WPRT group (73.3% vs 20%, P = 0.001). While grade 2 GU toxicity was also lower in the IM-WPRT patients (6.7% vs 16%), this difference did not reach statistical significance (P = 0.38).

Conclusion: IM-WPRT provides excellent coverage of the target structures while sparing critical neighboring structures in gynecology patients. Treatment is well tolerated with less acute GI toxicity than conventional WPRT. More patients and longer follow-up are needed to evaluate the full merits of this approach.