Biological Planning of Radiation Dose Based on In Vivo Dosimetry for Postoperative Vaginal-Cuff HDR Interventional Radiotherapy (Brachytherapy)

Tamer Soror,Luca Tagliaferri,György Kovács,Ramin Chafii,Valentina Lancellotta

doi:10.3390/biomedicines9111629

Abstract

(1) Background: Postoperative vaginal-cuff HDR interventional radiotherapy (brachytherapy) is a standard treatment in early-stage endometrial cancer. This study reports the effect of in vivo dosimetry-based biological planning for two different fractionation schedules on the treatment-related toxicities. (2) Methods: 121 patients were treated. Group A (82) received 21 Gy in three fractions. Group B (39) received 20 Gy in four fractions. The dose was prescribed at a 5 mm depth or to the applicator surface according to the distance between the applicator and the rectum. In vivo dosimetry measured the dose of the rectum and/or urinary bladder. With a high measured dose, the dose prescription was changed from a 5 mm depth to the applicator surface. (3) Results: The median age was 66 years with 58.8 months mean follow-up. The dose prescription was changed in 20.7% of group A and in 41% of group B. Most toxicities were grade 1–2. Acute urinary toxicities were significantly higher in group A. The rates of acute and late urinary toxicities were significantly higher with a mean bladder dose/fraction of >2.5 Gy and a total bladder dose of >7.5 Gy. One patient had a vaginal recurrence. (4) Conclusions: Both schedules have excellent local control and acceptable rates of toxicities. Using in vivo dosimetry-based biological planning yielded an acceptable dose to the bladder and rectum.

Highlights

In developed countries, endometrial cancer is the most common gynecological malignancy
Most of the patients presented with an early-stage disease, where postoperative vaginal-cuff interventional radiotherapy was found to be non-inferior to postoperative external beam radiation treatment (EBRT) with equivalent rates of local vaginal recurrences as well as distant metastases [2,3]
This study reports the clinical outcomes and the treatment-related toxicity following postoperative adjuvant VBT for early-stage endometrial cancer in two fractionation schedules using In vivo dosimetry (IVD)-based biological planning

Summary

Introduction

Endometrial cancer is the most common gynecological malignancy. Most of the patients presented with an early-stage disease, where postoperative vaginal-cuff interventional radiotherapy (brachytherapy, VBT) was found to be non-inferior to postoperative external beam radiation treatment (EBRT) with equivalent rates of local vaginal recurrences as well as distant metastases [2,3]. Compared with EBRT or EBRT combined with VBT, VBT has better late toxicity sequences and offers a better quality of life. In addition to global health status, patients treated with VBT alone had a better social function [4,5,6,7,8]. The use of EBRT or EBRT combined with HDR-VBT resulted in higher treatment costs and higher toxicity without the survival benefit as compared to BT alone [9,10,11]

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Discussion

Conclusion