Para-aortic and pelvic extended-field radiotherapy for advanced-stage uterine cancer: dosimetric and toxicity comparison between the four-field box and intensity-modulated techniques

A. Rabinovich, L. Bernard, A.V. Ramanakumar, G. Stroian, W.H. Gotlieb, S. Lau, B. Bahoric

Abstract


Background

In patients with advanced-stage endometrial carcinoma (eca), extended-field radiotherapy (efrt) is traditionally delivered by the 3-dimensional conformal (3d-crt) 4-field box technique. In recent years, the use of intensity-modulated radiotherapy (imrt) in gynecologic cancers has increased. We compared the delivery of efrt by the 3d-crt and contemporary imrt techniques.

Methods

After surgical staging and adjuvant chemotherapy in 38 eca patients, efrt was delivered by either imrt or 3d-crt. Doses to the organs at risk, side effects, and outcomes were compared between the techniques.

Results

Of the 38 eca patients, 33 were stage iiic, and 5 were stage ivb. In the imrt group, maximal doses to rectum, small intestine, and bladder were significantly higher, and mean dose to bladder was lower (p < 0.0001). Most acute gastrointestinal, genitourinary, and hematologic side effects were grade i or ii and were comparable between the groups. In long-term follow-up, only grade 1 cystitis at 3 months was statistically higher in the imrt patients. No grade iii or iv gastrointestinal or genitourinary toxicities were observed. No statistically significant differences in overall and disease-free survival or recurrence rates were observed between the techniques.

Conclusions

In advanced eca patients, imrt is a safe and effective technique for delivering efrt to the pelvis and para-aortic region, and it is comparable to the 3d-crt 4-field box technique in both side effects and efficacy. For centres in which imrt is not readily available, 3d-crt is a valid alternative.


Keywords


Extended-field radiotherapy; intensity-modulated radiotherapy; 3-dimensional conformal 4-field box technique

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DOI: http://dx.doi.org/10.3747/co.22.2727






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ISSN: 1198-0052 (Print) ISSN: 1718-7729 (Online)