Rectal Complication Following Radical Radiotherapy in Carcinoma of the Uterine Cervix

Kim, Won Dong; Park, Woo Yoon

Abstract

PURPOSE: This study evaluated the late rectal complications in cervix cancer patients following treatment with external beam radiotherapy (EBRT) and high dose rate intracavitary radiation (HDR ICR). The factors affecting the risk of developing late rectal complications and its incidence were analyzed and discussed.
MATERIALS AND METHODS
The records of 105 patients with cervix cancer who were treated with radical radiotherapy using HDR ICR between July, 1995 and December, 2001 were retrospectively reviewed. The median dose of EBRT was 50.4 Gy (41.4~56.4 Gy) with a daily fraction size of 1.8 Gy. A total of 5~7 (median: 6) fractions of HDR ICR were given twice weekly with a fraction size of 4~5 Gy (median: 4 Gy) to A point using an Ir (Iridium)-192 source. The median dose of ICR was 24 Gy (20~35 Gy). During HDR ICR, the rectal dose was measured in vivo by a semiconductor dosimeter. The median follow-up period was 32 months, ranging from 5 to 84 months.
RESULTS
Of the 105 patients, 12 patients (11%) developed late rectal complications; 7 patients with grade 1 or 2, 4 patients with grade 3 and 1 patient with grade 4. Rectal bleeding was the most frequent chief complaint. The complications usually began to occur 5~32 (median: 12) months after the completion of radiotherapy. Multivariate analysis revealed that the measured cumulative rectal BED over 115 Gy3 (Deq over 69 Gy) and the depth (D) of a 5 Gy isodose volume more than 50 mm were the independent predictors for late rectal complications.
CONCLUSION
With evaluating the cumulative rectal BED and the depth of a 5 Gy isodose volume as predictors, we can individualize treatment planning to reduce the probability of late rectal complications.