Intraoperative electron beam radiotherapy and perioperative high-dose-rate brachytherapy in previously irradiated oligorecurrent gynecological cancer: clinical outcome analysis.

BACKGROUND: Pelvic recurrences from previously irradiated gynecological cancer lack solid evidence for recommendation on salvage. METHODS: A total of 58 patients were included in this clinical analysis. Salvage surgery was performed for locoregional relapse within previously irradiated pelvic area after initial surgery and adjuvant radiotherapy or radical external beam radiotherapy. The primary tumor diagnosis included cervical cancer (n = 47, 81%), uterine cancer (n = 4, 7%), and other types (n = 7, 12%). Thirty-three patients received adjuvant IOERT (1984-2000) at a median dose of 15 Gy (range 10-20 Gy) and 25 patients received adjuvant PHDRB (2001-2016) at a median dose of 32 Gy (range 24-40 Gy) in 6, 8, or 10 b.i.d. fractions. RESULTS: The median follow-up was 5.6 years (range 0.5-14.2 years). Twenty-nine (50.0%) patients had positive surgical margins. Grade ≥ 3 toxic events were recorded in 34 (58.6%) patients. The local control rate at 2 years was 51% and remained stable up to 14 years. Disease-free survival rates at 2, 5, and 10 years were 17.2, 15.5, and 15.5%, respectively. Overall survival rates at 2, 5, and 10 years were 58.1, 17.8, and 17.8%, respectively. CONCLUSIONS: IOERT and PHDRB account for an effective salvage in oligorecurrent gynecological tumors. Patients with previous pelvic radiation suitable for salvage surgery and at risk of inadequate margins could benefit from adjuvant reirradiation in form of IOERT or PHDRB. However, the rate of severe grade ≥ 3 toxicity associated with the entire treatment program is relevant and needs to be closely counterbalanced against the expected therapeutic gain.

Time to loading and locoregional control in perioperative high-dose-rate brachytherapy: The tumor bed effect revisited.

PURPOSE: To determine whether the time to loading (TTL) affects locoregional control. METHODS AND MATERIALS: Locoregional control status was determined in 301 patients enrolled in several perioperative high-dose-rate brachytherapy (PHDRB) prospective studies conducted at the University of Navarre. The impact of the time elapsed from catheter implantation to the first PHDRB treatment (TTL) was analyzed. Patients treated with PHDRB alone (n = 113), mainly because of prior irradiation, received 32 Gy in eight twice-a-day treatments or 40 Gy in 10 twice-a-day treatments for negative or close/positive margins, respectively. Patients treated with PHDRB + external beam radiation therapy (EBRT) (n = 188) received 16 Gy in four twice-a-day treatments or 24 Gy in six twice-a-day treatments for negative or close/positive margins followed by 45 Gy of EBRT in 25 treatments. RESULTS: After a median followup of 6.5 years (range, 2-13.6+), 113 patients have failed (37.5%), 65 in the PHDRB-alone group (57.5%) and 48 in the combined PHDRB + EBRT group (25.5%). Patients who started PHDRB before Postoperative Day 5 had a 10-year locoregional control rate of 66.7% and patients who started PHDRB on Postoperative Day 5 or longer had a 10-year locoregional control rate of 51.8% (p = 0.009). Subgroup analysis detected that this difference was only observed in the recurrent cases treated with PHDRB alone (Subset 2; n = 99; p = 0.004). No correlation could be detected between locoregional control rate and TTL in the other patient subsets although a trend toward a decreased locoregional control rate after a longer TTL was observed when they were grouped together (p = 0.089). CONCLUSIONS: Patients should start PHDRB as soon as possible to maximize locoregional control especially in those recurrent cases treated with PHDRB alone. The time effect in other disease scenarios is less clear.

A proposal for the stratification of the risk of locoregional failure after surgical resection, perioperative high dose rate brachytherapy, and external beam irradiation: the University of Navarre predictive model.

PURPOSE: To develop a simple clinical model predictive of locoregional failure after complete surgical resection followed by perioperative high-dose-rate brachytherapy (PHDRB) and external beam irradiation (EBRT). PATIENT AND METHODS: Patients (n=166) enrolled in several PHDRB prospective studies conducted at the University of Navarre were analyzed. PHDRB was given to total doses of 16 Gy/4 b.i.d. or 24 Gy/6 b.i.d. treatments for negative or close/positive margins along with 45Gy of EBRT. RESULTS: After a median followup of 7.4 years (range, 3-12+), 50 patients have failed and 116 remain controlled at last followup. Tumor size, with a cutoff point set at 3cm (p=0.041) and margin status (positive and <1mm vs. negative ≥1mm, p=0.0001) were independent predictors of locoregional control. These two parameters were used to develop a four-tiered, hierarchical scoring system that stratified patients into low-risk (negative ≥1mm margins and size ≤3cm), intermediate-risk (negative ≥1mm margins, and size >3cm), high-risk (positive and <1mm margins and size ≤3cm), and very high-risk categories (positive and <1mm margins and size >3cm). This classification yields 5-year locoregional control rates of 92.3%, 78.0%, 65.5%, and 48.0% for low-, intermediate-, high-, and very high-risk categories, respectively. The predictive ability of the model is highly significant (p=0.0001) with an area under the curve of 0.72 (0.64-0.81). CONCLUSIONS: The risk of locoregional failure after combined surgical resection, PHDRB, and EBRT is mainly determined by the number of residual clonogens, which is inversely proportional to the status of the surgical margins and directly related to the size of the resected tumor. These two parameters generate a four-tiered predictive model that seems to be valid for a number of different common tumors and clinical settings.