Prognostic factors in cutaneous apocrine carcinoma: a single-institution retrospective study of 32 patients.

Background: Cutaneous apocrine carcinoma (CAC) is a rare adnexal carcinoma. Limited data exists on the demographics and overall survival (OS) of patients with CAC; thus, there is no consensus on surgical management. This study aimed to examine demographic and survival data of patients with CAC to determine optimal surgical management.

Methods: A single-center retrospective cohort study was conducted at the National Cancer Center Hospital in Tokyo between 2005 and 2022. Patients with a histologically-confirmed CAC diagnosis were identified and data on patient demographics, OS, and lymph node (LN) status were gathered.

Results: Thirty-two patients were included (median age, 65.5 years; male-female ratio, 15:1). The most common involvement site was the axilla (87.5%). Of the nine patients in the clinical local stage, pathological LN metastases were found in five patients. Either pathological LN or distant metastases were present in 75% of the patients at initial diagnosis. The most common initial surgical treatments included wide local excision and complete LN dissection. Across cohorts, the median OS was 39 months. Patients with ≥ 4 LN metastases had reduced recurrence-free survival and OS compared to those with ≤ 3 LN metastases (p = 0.042, p = 0.041, respectively). The OS was not remarkably different between patients who did and did not receive postoperative radiation therapy.

Conclusions: Since CAC has a high rate of LN metastasis-and the number of LN metastases is a significant prognostic factor-LN evaluation should be considered for patients with CAC as initial treatment. Nonetheless, ≥ 4 LN metastases can be a poor prognostic factor for CAC.