Salvage Re-irradiation With Single-modality Interstitial Brachytherapy for the Treatment of Recurrent Gynaecological Tumours in the Pelvis: A Multi-institutional Study

Abstract

Aims: Recurrent gynaecological tumours can cause significant morbidity with limited salvage options. This study investigates the strategy of salvage singlemodality interstitial brachytherapy (SM-ISBT) for recurrent gynaecological pelvic cancer at two specialised ISBT centres. Materials and methods: Patients who had received salvage SM-ISBT for pelvic recurrence of gynaecological cancers from September 2008 to January 2017 were included. None had distant metastasis at the time of recurrence. Local control, progression-free and overall survival and long-term toxicities were evaluated. Results: Twenty-six patients with a median follow-up of 24 months (range 2.5e106.3 months) after SM-ISBT were included. Primary cancer sites were endometrium (20), cervix (4), vulva (1) and vagina (1). All patients had prior whole-pelvic external beam irradiation and 16 had prior brachytherapy. The median disease-free survival prior to SM-ISBT was 20.3 months (interquartile range 9.9e30.5). SM-ISBT was delivered with high dose rate technique over three to six fractions. The median high-risk clinical target volume was 34.6 cm 3 , with a median D90 of 29.1 Gy (range 16.1e64.6). The median bladder, rectum and sigmoid D2cm 3 were 15.5, 18.7 and 3.7 Gy, respectively. After SM-ISBT, complete and partial responses were achieved in 17 (64%) and 5 (19%) patients, respectively. Two (7.4%) patients had grade 3 toxicities (both vaginal stenosis), with no grade 4 complications. Eighteen patients (69%) recurred, including local, regional and metastatic in 14 (54%), 8 (30%) and 5 (19%) patients, respectively. Two-year local control, progression-free survival and overall survival were 50, 38 and 78%, respectively. In follow-up, 12 patients (46%) remained in local control. Conclusions: Salvage SM-ISBT re-irradiation for pelvic recurrence of gynaecological malignancies was feasible and safe. With limited salvage options, the local control obtained in more than a quarter of patients seems reasonable. Further efforts are needed to establish a consensus about the optimal patient selection, dose fractionation, implant technique and combination with systemic therapies.

Image-Guided Brachytherapy for Salvage Reirradiation: A Systematic Review

“…Over the past 20 years, 14 retrospectives series, and one phase II prospective study with only few patients [31], reported clinical experiences of high dose rate (HDR) or low dose rate (LDR) 3D-IGBT in previously irradiated pelvic recurrences of gynecologic malignancies (Table 1) [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45]. In nine of those, 100% of the population received prior BT, prior EBRT, or a combination of EBRT followed with BT [31][32][33]36,40,41,[43][44][45]. In the six remaining articles, only a variable subset of patients (from 10% to 85.7% of the studied population) received IGBT in a re-irradiation setting [34,35,[37][38][39]42].…”

“…The vast majority of the studies focused on isolated local recurrences, occurring in the vagina, paravaginal, pelvic sidewall, cervix (if hysterectomy was not performed as a part of the initial treatment), vulva or sub-urethra [31][32][33][34][35][36][37][38][39][40][41][42][43]45]. In only one study, regional and distant metastasis were not excluded, and occurred simultaneously to local relapse in four patients (two patients (9.1%) with nodal involvement and two patients (9.1%) with distant oligometastasis) [44].…”

“…Regarding the size of pelvic recurrences, the median tumor maximum diameter was reported in six studies [33,34,37,39,42,44], ranging from 20.5 to 36 mm (median, 24 mm), with the largest tumor diameter measuring up to 100 mm. Other studies reported median target (GTV or CTV) volumes, ranging from 6 to 50.35 cc (median, 31.4 cc) [32,41,45]. One study reported an average CTV volume of 60.9 cc, with the largest CTV volume up to 165.3 cc [31].…”

“…The interval time between first radiation and the recurrence was mentioned in nine studies and is reported as treatment-free interval (TFI) in Table 1 [32,33,35,[39][40][41][43][44][45]. The median TFI ranged from 13 to 61 months (median, 23 months).…”

“…The median TFI ranged from 13 to 61 months (median, 23 months). Among these studies, three proposed re-irradiation if TFI was less than 6 months [41,43,45], three considered a minimal TFI of at least 6 months [32,39,40], and one of at least 1 year [44].…”