Preliminary results of a vaginal constraint for reducing G2 late vaginal complications after postoperative brachytherapy in endometrial cancer: a prospective analysis

PurposeTo evaluate the preliminary results of the use of 68 Gy EQD2(α/β=3 Gy) as a dose limit to the lowest dose in the most exposed 2 cm3 of the vagina in order to reduce G2 late vaginal problems in postoperative endometrial carcinoma (EC).MethodsFrom November 2016 to October 2019, 69 postoperative EC patients receiving vaginal brachytherapy (VBT) ± external beam radiotherapy (EBRT) were prospectively analyzed. The median EBRT dose was 45 Gy (range: 44–50.4 Gy), 1.8−2 Gy/day, 5 fractions(Fr)/week. VBT was administered with the following schedule: 1Fr of 7 Gy after EBRT and 2 daily Fr × 7.5 Gy in exclusive VBT. The dose was prescribed at 0.5 cm from the applicator surface with an active length of 2.5 cm; 56 patients were treated with vaginal cylinders (49–3.5 cm, 6–3 cm, and 1–2.5 cm) and 13 with the colpostat technique. The overall VBT dose was adjusted to meet the vaginal restriction of < 68 Gy EQD2(α/β=3 Gy) at 2 cm3. Late toxicity was prospectively assessed using RTOG scores for bladder and rectum, and the objective LENT-SOMA criteria for vagina.ResultsWith a median follow-up of 31.0 months, no vaginal-cuff recurrences were found. Late toxicity: only 1G1(1.4%) rectal toxicity; 21G1(30.4%) and 3G2(4.3%) vaginal complications. Only one (1.4%) of 3 G2 manifested as vaginal shortening.ConclusionsIn postoperative EC patients treated with VBT, only one developed G2 vaginal stenosis with the use of 68 Gy EQD2(α/β=3 Gy) as a dose constraint. These preliminary results seem to indicate the value of this dose limit for reducing G2 vaginal stenosis. Nonetheless, these findings should be confirmed in a larger number of patients with longer follow-up.

Preliminary results of a vaginal constraint for reducing G2 late vaginal complications after postoperative brachytherapy in endometrial cancer: a prospective analysis.

PURPOSE: To evaluate the preliminary results of the use of 68 Gy EQD2(α/ß=3 Gy) as a dose limit to the lowest dose in the most exposed 2 cm3 of the vagina in order to reduce G2 late vaginal problems in postoperative endometrial carcinoma (EC). METHODS: From November 2016 to October 2019, 69 postoperative EC patients receiving vaginal brachytherapy (VBT) ± external beam radiotherapy (EBRT) were prospectively analyzed. The median EBRT dose was 45 Gy (range: 44-50.4 Gy), 1.8-2 Gy/day, 5 fractions(Fr)/week. VBT was administered with the following schedule: 1Fr of 7 Gy after EBRT and 2 daily Fr × 7.5 Gy in exclusive VBT. The dose was prescribed at 0.5 cm from the applicator surface with an active length of 2.5 cm; 56 patients were treated with vaginal cylinders (49-3.5 cm, 6-3 cm, and 1-2.5 cm) and 13 with the colpostat technique. The overall VBT dose was adjusted to meet the vaginal restriction of < 68 Gy EQD2(α/ß=3 Gy) at 2 cm3. Late toxicity was prospectively assessed using RTOG scores for bladder and rectum, and the objective LENT-SOMA criteria for vagina. RESULTS: With a median follow-up of 31.0 months, no vaginal-cuff recurrences were found. Late toxicity: only 1G1(1.4%) rectal toxicity; 21G1(30.4%) and 3G2(4.3%) vaginal complications. Only one (1.4%) of 3 G2 manifested as vaginal shortening. CONCLUSIONS: In postoperative EC patients treated with VBT, only one developed G2 vaginal stenosis with the use of 68 Gy EQD2(α/ß=3 Gy) as a dose constraint. These preliminary results seem to indicate the value of this dose limit for reducing G2 vaginal stenosis. Nonetheless, these findings should be confirmed in a larger number of patients with longer follow-up.

Postoperative endometrial carcinoma treated with external beam irradiation plus vaginal-cuff brachytherapy. Is there a dose relationship with G2 vaginal complications?

AIM: To analyse the possible relationship between the EQD2(α/ß=3Gy) at 2 cm3 of the vagina and late toxicity in vaginal-cuff-brachytherapy (VBT) after external-beam-irradiation (EBRT) for postoperative endometrial carcinoma (EC). MATERIALS AND METHODS: From 2014 to 2016, 62 postoperative EC patients were treated with EBRT + VBT. The median EBRT dose was 45 Gy (44 Gy-50.4 Gy). VBT involved a single 7 Gy dose. Toxicity was prospectively evaluated using the RTOG score for the rectum and bladder and the objective LENT-SOMA criteria for the vagina. EQD2(α/ß = 3Gy) at 2 cm3 of the most exposed part of the vagina was calculated by the sum of the EBRT + VBT dose. Statistics: Boxplot, Student's t and Chi-square tests and ROC curves. RESULTS: Mean follow-up: 39.2 months (15-68). Late toxicity: bladder:0 patient; rectum:2 patients-G1; Vagina: 26 patients-17G1, 9G2; median EQD2(α/ß=3Gy) at 2 cm3 in G0-G1 patients was 70.4 Gy(SD2.36), being 72.5 Gy(SD2.94) for G2p. The boxplot suggested a cut-point identifying the absence of G2: 100 % of G2p received >68 Gy, ROC curves showed an area under the curve of 0.72 (sensitivity of 1 and specificity of 0.15). CONCLUSIONS: Doses >68 Gy EQD2(α/ß=3Gy) at 2 cm3 to the most exposed area of the vagina were associated with late G2 vaginal toxicity in postoperative EC patients treated with EBRT + VBT suggesting a very good dose limit to eliminate the risk of G2 late toxicity. The specificity obtained indicates the need for prospective analyses.