Salvage radiotherapy for recurrent hypopharyngeal and laryngeal squamous cell carcinoma (SCC) after first-line treatment with surgery alone: a 10-year single-centre experience

Purpose: Salvage surgery of recurrent hypopharyngeal and laryngeal squamous cell carcinoma (SCC) results in limited local control and survival rates. As a result of recent technological progress, radiotherapy (RT) has become a valuable, potentially curative therapeutic option. Thus, we aimed to determine prognostic factors for survival outcome in order to optimize patient selection for salvage radiotherapy after failure of first-line treatment with surgery alone in this special patient cohort. Methods: Seventy-five patients (85% male, median age of 64 years) underwent salvage RT in a secondary setting for recurrent hypopharyngeal or laryngeal SCC after prior surgery alone between 2007 and 2017. On average, patients were treated with one prior surgery (range 1–4 surgeries). Median time between surgery and salvage RT was 7 months (range 1–47 months) for initially advanced tumors (T3/4, N+, extracapsular spread) and 18 months (range 5–333 months) for initially early stage tumors. The majority of patients received concomitant chemotherapy (n = 48; 64%) or other kind of systemic treatment concurrent to radiotherapy (n = 10; 13%). Results: Median follow-up was 41 months (range 3–120 months). Overall, fifteen patients were diagnosed with local failure (all were in-field) at last follow-up (20%). Median time to recurrence was 35 months (range 3–120 months) and 3-year local progression-free survival (LPFS) was 75%, respectively. Dose-escalated RT with 70.4 Gy applied in 2.1 Gy or 2.2 Gy fractions corresponding an EQD2 > 70 Gy (p = 0.032) and the use of concomitant cisplatin weekly chemotherapy (p = 0.006) had a significant positive impact on LPFS. 3-year OS and DPFS were 76 and 85%, respectively. No toxicity-related deaths occurred. Reported grade > 3 side effects were rare (n = 4/70, 6%). Conclusion: Salvage radiotherapy resulted in excellent local control rates while radiation dose and the use of cisplatin weekly chemotherapy were identified as prognostic factors for LPFS. Nevertheless, patient selection for curative salvage treatment remains challenging