ESTRO 2024 - Abstract Book

S210

Brachytherapy - Gynaecology

ESTRO 2024

below 50 years of age. All patients in the study group had bilateral parametrial involvement at presentation. 5/21 patients had initial pelvic nodal involvement 66% of patients completed the entire treatment within 60 days but there was inevitable prolongation of overall treatment time (OTT) in 7 patients to beyond 60 days. 14/21 patients underwent 2 IC-ISBT applications with 4 fractions.7/21 patients underwent 1 or 2 ICBT applications followed by IC-ISBT. Mean HRCTV volume = 48 +/- 11cc. Lateral distance of 100% isodose at level of Point A= 2.36±0.21cm. Dose Volume parameters achieved are elaborated in the table below Median follow-up: 8 (4-23) months.18/21 achieved complete response, 2/21 - progressive disease, 1/21 lost to follow-up. 2/18 patients with CR developed distant relapse. 5/21 and 4/21 had grade 2 bladder and rectal acute toxicity respectively. None had grade 3/4 bladder/ rectal toxicities.

Parameters

Median dose (IQR)

Median Dose (IQR)

p value

Total Delivered Median Doses (Gy)

(40 applications)

(paired t test)

PLAN A (Gy)

Plan B (Gy)

(four fractions)

per fraction

per fraction

HRCTV D90

5.6(5.33-5.9)

7.2(7.05-7.5)

<0.001 *

83.9(78.5, 87.2)

IRCTV D90

3.75(3.4-4.4)

4.53(3.85-4.9)

<0.001 *

67.9(63.76,70.32)

Rectum D2cc

3.4(3-4.3)

3.6(2.9-4.1)

0.769

64.0(61.6, 72.0)

Bladder D2cc

4.97(4.5-5.05

5(4.8-5.3)

0.015 *

76(69, 78)

Sigmoid D2cc

3.7(3.3-4.2)

3.9(3.3-4.4)

0.031 *

65.8(61.4, 70.0)

Maximum Lateral distance covered at level of Point A

1.57(1.5-1.75)

2.37(2.2-2.5)

<0.001 *

Table: Dose-Volume Parameters achieved for a Prescription of 7 Gy

Plan A

Plan B

Fig : Comparison of dose distribution between Plan A & Plan B