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.