Oncologic outcomes in primary squamous cell carcinoma of the auricle: a retrospective cohort analysis

Purpose: The prognostic significance of auricular location in cutaneous squamous cell carcinoma (cSCC) is controversial. We aimed to characterize risk factors for, and evaluate the cumulative incidence of, locoregional recurrence in a cohort of patients with primary auricular cSCC. Methods: The study design was a single-institution retrospective cohort review from 1/2007 to 12/2016. Results: Among 851 potentially eligible individuals, 178 patients with primary auricular cSCC met strict criteria for inclusion. Median follow-up was 32 months, 93% were AJCC 8th edition (AJCC8) stage I and 6% were AJCC8 stage II. Most underwent Mohs micrographic surgery (MMS; 97%) and the remainder underwent wide local excision ± parotidectomy ± neck dissection ± adjuvant therapy (3%). Recurrences occurred in seven patients (4%): six were local and one was regional. The 3-year cumulative incidence of local and regional recurrence for AJCC8 stage I–II tumors were 1% (95% CI 0–5%) and 0%, respectively. Among ten patients upstaged to pT3 disease who underwent MMS alone, none recurred locoregionally. Compared to their respective counterparts, advanced stage, PNI, and LVI associated with a significantly increased risk of locoregional recurrence. Conclusions: Our findings suggest that auricular location may not be a significant risk factor for cSCC staging systems. In the absence of other risk factors, unimodal therapy appears adequate for patients with primary, stage I–II auricular cSCC. The prognostic significance of pT3 auricular cSCC stage due to depth of invasion alone should be evaluated further.