Clinical outcome of high-dose-rate interstitial brachytherapy in vulvar cancer: A single institutional experience

The aim was to evaluate the toxicities and survival of patients with inoperable vulvar cancer treated using brachytherapy (BT).

Patients treated at Kuopio University Hospital, Finland, during years 2007-2022 were retrospectively analyzed.

Twenty-seven patients with vulvar cancer received high-dose-rate (HDR) interstitial brachytherapy (BT), most of them after external beam radiotherapy (EBRT). Nineteen had primary locally advanced vulvar cancer, and 8 had recurrent cancer. The mean EBRT prescription dose was 48.5 Gy (39-60 Gy) in 13-33 fractions. Eighteen patients (67%) had cisplatin as a radiosensitizer. EBRT was followed by BT (16-36 Gy in 3-8 fractions). The mean HR-CTV (high-risk clinical target volume) D90 EBRT + BT dose was 71.2 Gy (EQD₂). The mean follow-up time was 30 months. The 2-year progression-free survival (PFS) was 41% in the primary cancer group and 38% in the recurrence group. The 2-year overall survival (OS) was 56% and 63%, respectively. There were 12/19 (63%) recurrences in the primary cancer group. In the recurrent cancer group, 4 out of 8 (50%) patients had a subsequent recurrence. 7/27 (26%) patients suffered from grade 3-4 late toxicities. Before EBRT, the median size of the tumors was 3.8 cm. Patients with a tumor ≥ 3.8 cm had significantly worse OS than patients with tumors <3.8 cm, 45 months and 54 months, respectively (p = 0.022). The use of radiosensitizing chemotherapy also predicted better overall survival (p = 0.037).

Definitive radiation therapy, including EBRT and BT, is a potential option in the management of inoperable vulvar cancer. To avoid toxicities, the proper radiation doses are to be found.