What is the normal tissues morbidity following Helical Intensity Modulated Radiation Treatment for cervical cancer?

Abstract

Background and purpose: To report on normal tissues morbidity following IMRT for cervix cancer.

Material and methods: The first 61 patients of a prospective series were included. 50 Gy to the PTV 1(pelvis) and 60 Gy to the PTV 2 (centro-pelvic disease and GTV nodes) were delivered concomitantly in 28 fractions, followed by a brachytherapy boost. For the small bowel, 50 Gy was the maximal dose, while V45 and V40 had to be <50 cc and 200 cc, respectively. For the bladder, rectum and sigmoid structures, 60 Gy was the maximal dose, and V45 and V40 had to be <20% and <50%. Acute and late toxicity data were prospectively collected.

Results: The median follow-up period was 40 months (range: 23-60). 30% and 90% of acute and moderate late side effects were reported respectively. Considering the AUC data of the organs at risk (OAR) DVH, late morbidity and doses were significantly linked (p⩽0.03), predominantly between 10 Gy and 40 Gy, considering the small bowel and sigmoid colon. The high dose regions exhibited no significant impact.

Conclusion: The moderate dose volumes represent the predominant cause of morbidity after IMRT. Prospective trials are thus required to investigate new ways of dose distribution within the OAR.

Keywords: Cervix cancer; Helical Intensity Modulated Radiation Treatment; IMRT; Morbidity.