Cutaneous squamous cell carcinoma treated with Mohs micrographic surgery in Australia I. Experience over 10 years

Background: Only a few reports have been published on the long-term outcome of surgical excision of cutaneous squamous cell carcinoma (SCC). Objective: Our purpose was to report the clinical findings and 5-year recurrence rate of all patients with cutaneous SCC treated with Mohs micrographic surgery (MMS) in Australia between 1993 and 2002. Method: This prospective, multicenter case series included all patients with SCC who were monitored by the Skin and Cancer Foundation. The main outcome measures were patient demographics, reason for referral, duration of tumor, site, preoperative tumor size, postoperative defect size, recurrences before MMS, histological subtypes, and 5-year recurrence after MMS. Results: The case series comprised 1263 patients (25.7% female and 74.3% male; P <.0001) with a mean age of 66 +/- 13 years. In 61.1% of cases the lesion was a primary tumor, and in 38.9% it was a recurrent tumor. Most of the tumors (96.5%) were on the head and neck area, Recurrent tumors were larger than primary tumors (P <.0001), had a larger postexcision defect (P <.0001), required more levels of excision (P <.0001), and had more cases of subclinical extension (P=.002). Recurrence after MMS was diagnosed in 15 of the 381 patients (3.9%) who completed the 5-year follow-up after MMS. The recurrence rate was 2.6% in patients with primary SCC and 5.9% in patients with previously recurrent SCC (P <.001). Conclusion: This large prospective series of SCC managed by MMS is characterized by a high percentage of high-risk tumors. The low 5-year recurrence rate with MMS emphasizes the importance of margin-controlled excision.