American Brachytherapy Society survey regarding practice patterns of postoperative irradiation for endometrial cancer: Current status of vaginal brachytherapy

Abstract

To survey the current postoperative recommendations for radiotherapy (RT) in patients with endometrial cancer, with an emphasis on vaginal brachytherapy (VBT). In August 2003, a 32-item questionnaire was mailed to a random sample of 2396 members of the American Society for Therapeutic Radiology and Oncology and the American Brachytherapy Society. The sample excluded members-in-training, physicists, and non-U.S. members. A follow-up mailing was conducted in November 2003. Those who had not treated any patient in the previous year for endometrial carcinoma were instructed to indicate so at the beginning of the questionnaire and return it without responding to any other item. Responses were tabulated to determine the relative frequency distribution. of the 2396 surveys sent out, 757 were returned, for a response rate of 31.6%. Of those who responded, 551 (72.8%) had performed postoperative irradiation for endometrial cancer and were included in this study. Of the 551 respondents, 99.8% had delivered external beam RT to some endometrial cancer patients. An increasing trend was found toward referrals for VBT; 91.5% of those who treated endometrial cancer performed VBT. The vaginal target most often irradiated was the upper vagina in 40.7%, upper 4-5 cm in 54.5%, and the entire vagina in 4.9%; 21.3% placed clips at the vaginal apex for applicator verification. The maximal dose to the bladder and rectum was recorded in 78.3% and 80.2% of patients, respectively. Of the respondents, 40% did not use low-dose-rate (LDR) VBT. The two most common LDR applicators were Delclos cylinders (29.7%) and Fletcher colpostats (29.3%). The mean boost dose delivered with LDR VBT when prescribed to the surface was 29.9 Gy and when prescribed to 0.5 cm was 23.8 Gy. When LDR therapy was used without external beam RT, the mean dose when prescribed to the surface was 56.8 Gy and when prescribed to 0.5 cm was 47.9 Gy. In 2002, 69.1% of respondents treated patients with high-dose-rate (HDR) VBT. Of the respondents, 90.6% used a single-channel vaginal cylinder, and 83.3% of cylinder users followed the curve of the cylinder to optimize dose, 67.9% adjusted the applicator position based on localization films, and 47% adjusted the applicator to be horizontal. The most common fractionation scheme when using HDR VBT as a boost was 5 Gy in three fractions prescribed to 0.5 cm (42.9%). The most common fractionation scheme used with HDR without external beam RT was 7 Gy in three fractions prescribed to 0.5 cm (41.8%). VBT is a common recommendation for postoperative adjuvant therapy for endometrial cancer. HDR appears to be the most popular approach, with a wide variety of dose fractionation schemes reported. Additional study is warranted to help define the ideal use of VBT.