INTRODUCTION
Topical imiquimod 5% cream has been investigated as off-label primary or adjuvant treatment for melanoma in situ, lentigo maligna (LM) type, although long-term follow-up data are lacking.1 Herein, we present a novel survival analysis based on a case series of 103 LM type (n = 81) or atypical intradermal melanocytic proliferation lesions (consistent with early/evolving LM) (n = 22), who were treated with topical imiquimod and followed up to 17 years thereafter. We report recurrence free survival (RFS) following primary (nonsurgical) or adjuvant treatment (after excision with narrow histologic margins [<1 mm] or histologically positive margins without visible pigmentation) between January 1, 2002 and March 31, 2019 and followed through November 15, 2019.
Treatment protocol was based on evolving best practices; patients were offered surgical resection as first-line therapy or off-label topical imiquimod 5% cream as second-line therapy. Patients were instructed to apply imiquimod five times weekly (weekdays) for 12 weeks with or without pre-treatment using two weeks of daily tazarotene 0.1% gel in order to elicit an appropriate inflammatory response, including erythema and scale.
There were 51 females and 52 males, with average age of 69.9 years (S = 10.4 years, range, 38–92 years). Additional case information is available in Table 1. Primary treatment occurred in 71 cases (68.9%) while 32 cases (31.3%) used imiquimod for adjuvant therapy after surgical resection with margins positive or narrowly excised for LM. Median follow-up was 5.1 years (mean = 6.2 years, S = 5.2 years, range, 0.08–17.1 years); 47 cases (45.6%) had >5 years follow-up, and 30 (29.1%) had >10 years. Lesions were assessed histologically, with post-treatment biopsy one month after completion of treatment when possible (64% of cases), and clinically, including Wood’s lamp for residual pigmentation. Suspected recurrences were re-biopsied at the time of clinical suspicion.
The survival analysis assigned one point each to eight risk factors; age >65 years old, history of invasive melanoma at site of treatment, previous failed excision, no pre-treatment with
Treatment protocol was based on evolving best practices; patients were offered surgical resection as first-line therapy or off-label topical imiquimod 5% cream as second-line therapy. Patients were instructed to apply imiquimod five times weekly (weekdays) for 12 weeks with or without pre-treatment using two weeks of daily tazarotene 0.1% gel in order to elicit an appropriate inflammatory response, including erythema and scale.
There were 51 females and 52 males, with average age of 69.9 years (S = 10.4 years, range, 38–92 years). Additional case information is available in Table 1. Primary treatment occurred in 71 cases (68.9%) while 32 cases (31.3%) used imiquimod for adjuvant therapy after surgical resection with margins positive or narrowly excised for LM. Median follow-up was 5.1 years (mean = 6.2 years, S = 5.2 years, range, 0.08–17.1 years); 47 cases (45.6%) had >5 years follow-up, and 30 (29.1%) had >10 years. Lesions were assessed histologically, with post-treatment biopsy one month after completion of treatment when possible (64% of cases), and clinically, including Wood’s lamp for residual pigmentation. Suspected recurrences were re-biopsied at the time of clinical suspicion.
The survival analysis assigned one point each to eight risk factors; age >65 years old, history of invasive melanoma at site of treatment, previous failed excision, no pre-treatment with
