Optimizing safety and efficacy in radiotherapy for external auditory canal cancer

External auditory canal cancer (EACC) is a rare and aggressive malignancy with no established standard treatment. The present study aimed to investigate the efficacy of radiotherapy (RT) for EACC. The data of 42 patients with EACC treated between January 2000 and August 2023 were retrospectively reviewed. Of these, 10 (24%) patients underwent surgery followed by RT (median dose, 60 Gy), whereas 32 (76%) underwent definitive RT (median dose, 66 Gy) and a total of 23 (72%) patients received concurrent chemotherapy with definitive RT. Overall survival (OS), local control (LC), progression-free survival (PFS) and toxicity were examined. The median age of patients was 65 years, and the median follow-up duration was 31.5 months (range: 6-120 months). In all patients, the 3-year OS, LC and PFS rates were 54.8, 65.5 and 49.0%, respectively. The 3-year OS, LC and PFS rates in patients who underwent surgery followed by RT, and those who underwent definitive RT were 90% vs. 42.9% (P=0.008), 100% vs. 53.9% (P=0.01) and 90% vs. 35.9% (P=0.003), respectively. No local recurrence occurred among those who underwent surgery followed by RT, although 50% of these patients had positive or close surgical margins. Grade ≥3 brain toxicities were observed in 3 (7.1%) patients, all of whom had T4 disease and underwent definitive RT with concurrent systemic chemotherapy. In conclusion, compared with definitive RT, surgery followed by RT was associated with favorable outcomes in patients with EACC. A multidisciplinary approach is crucial for optimizing treatment outcomes, especially for patients in the advanced stages of EACC.