Immunocryosurgery for non-superficial basal cell carcinoma: a pro-spective, open-label phase III study for tumours ≤ 2 cm in diameter.

Cryosurgery and topical imiquimod are established mono-therapies for superficial basal cell carcinoma (BCC) but are often insufficient for thicker BCCs. We present here a phase III, prospective, interventional, single-arm (cases only) study (trial registration: NCT01212562) to evaluate the feasibility and efficacy of cryosurgery (liquid nitrogen, open spray, 2 × 15 s; day 14) during 5 weeks' imiquimod ("immunocryosurgery") for primary, non-superficial BCC, ≤ 2 cm in diameter. Ninety-one consecutive patients with 134 basal cell carcinoma were evaluated. A total of 83 patients (124 tumours) started treatment, and 79 patients (119 tumours) completed at least one cycle of immunocryosurgery (feasibility: 95.2%; follow-up: 18-60 months). The efficacy after one treatment cycle was 95 ± 2% stable complete remissions (116/119 tumours cleared, 3/116 tumours relapsed: 6 treat-ment "failures"). Neither tumour size (p = 0.865) nor localization (p = 0.233) predicted outcome. Repeat immunocryosurgery controlled 5/6 treatment failures (overall efficacy: 99%). Lack of a conventionally treated control group is a limitation of this study. However, the results show a high therapeutic efficacy of immunocryosurgery in a large series of primary non-superficial BCC.