Determinants of complications and outcome in high-risk squamous cell head-and-neck cancer treated with perioperative high-dose rate brachytherapy (PHDRB).

PURPOSE: To determine the impact of a set of patient, tumor, and treatment factors on toxicity and outcome in patients with head-and-neck squamous cell cancer treated with surgical resection and perioperative high-dose rate brachytherapy (PHDRB) alone (single-modality [SM] group) (n = 46) or PHDRB combined with postoperative radiation or chemoradiation (combined-modality [CM] group) (n = 57). METHODS AND MATERIALS: From 2000 to 2008, 103 patients received PHDRB after complete macroscopic resection. SM patients received 32 or 40 Gy of PHDRB in 8 or 10 twice-daily treatments for R0 and R1 resections. CM patients received 16 or 24 Gy of PHDRB in 4 or 6 twice-daily treatments for R0 and R1 resections, followed by external radiation of 45 Gy in 25 fractions with or without concomitant chemotherapy.
RESULTS: Grade ≥4 complications according to the Radiation Therapy Oncology Group were more frequent in the SM group than in the CM group (p = 0.024). Grade ≥3 and ≥4 complications increased with the antecedent of prior irradiation (p = 0.032 and p = 0.006, respectively) and with TV(150) values of 13 mL or greater (p = 0.032 and p = 0.032, respectively). After a median follow-up of 34.8 and 60.8 months for SM and CM patients, respectively, patients with high-risk margins had a 9-year local control rate of 68.0% whereas patients with wider margins had a 9-year local control of 93.7% (p = 0.045). Patients with primary and recurrent tumors had 9-year actuarial locoregional control rates of 81.8% and 54.2%, respectively (p = 0.003). Patients with lymph-vascular space invasion (LVSI)-positive and LVSI-negative tumors had 9-year distant control rates of 62.8% and 81.6%, respectively (p = 0.034). Disease-free survival rates decreased in recurrent cases (p = 0.006) as well as in LVSI-positive patients (p = 0.035).
CONCLUSIONS: The complications observed are largely attributable to the antecedent of prior irradiation but can possibly be minimized by meticulous mapping and exhaustive planning to reduce TV(150) values. Patients with high-risk margins, LVSI-positive status, and recurrent disease have a higher risk of treatment failure, and therefore risk-directed treatment strategies are required.