Imiquimod cream trumps photodynamic therapy, 5-fluorouracil in superficial basal cell carcinoma
Imiquimod cream appears to be more effective than both methyl aminolevulinate photodynamic therapy (MAL-PDT) and 5-fluorouracil cream in the long-term treatment of superficial basal cell carcinoma (sBCC), as shown in a recent study.
The study randomized 601 adult patients with a primary, histologically proven sBCC to receive MAL-PDT (n=202), imiquimod 5% cream (n=198) or 5-fluorouracil 5% cream (n=201). MAL-PDT involved two single treatments with a 1-week interval (fluence, 630 nm; dose, 37 J/cm2). Imiquimod was applied once daily for 5 consecutive days a week for 6 weeks, while 5-fluorouracil was applied twice daily for 4 weeks.
Over a median follow-up of 64 months, tumour recurrences occurred in 70 patients in the MAL-PDT group, 36 in the imiquimod group and 57 in the 5-fluorouracil group. The primary endpoint of the probability of tumour-free survival 5 years after treatment was 62.7 percent with MAL-PDT, 80.5 percent with imiquimod and 70.0 percent with 5-fluorouracil. [J Invest Dermatol 2018;138:527-533]
Cox proportional hazards models showed that the risk of treatment failure was significantly lower with imiquimod vs MAL-PDT (hazard ratio [HR], 0.48; 95 percent CI, 0.32–0.71; p<0.001) or 5-fluorouracil (HR, 0.65; 0.43–0.98; p=0.04). Furthermore, 5-fluorouracil was not inferior to MAL-PDT, having an HR of 0.74 (0.53–1.05; p=0.09).
The finding that tumour-free survival with imiquimod was 80.5 percent after 5 years of follow-up is in line with the results of a recent randomized controlled trial reporting a 5-year success rate of 83.8 percent with topical imiquimod cream vs surgical excision in 501 patients with sBCC. Two other studies on imiquimod treatment for sBCC reported 5-year success rates of 80.4 percent and 77.9 percent. [J Invest Dermatol 2017;137:614-619; Cutis 2010;85:318-324; Eur J Dermatol 2008;18:677-682]
“Based on the 5-year probabilities of remaining free from recurrence [in the current study], one recurrence can be prevented for every 5.6 patients (3.7–11.4) treated with imiquimod instead of MAL-PDT and for every 9.5 patients (5.2–57.4) treated with imiquimod instead of 5-fluorouracil,” the authors said.
Furthermore, while all three studied noninvasive therapies are considered an effective treatment for sBCC in the European guidelines, the present data suggest that 5% imiquimod cream should be the noninvasive treatment of choice, they continued. “PDT and 5-fluorouracil could be reserved for situations where there is a relative or absolute contraindication to using imiquimod.”
The study was limited by the number of patients lost to follow-up and the censoring of patient observations at exactly 36 months after treatment (the planned date). The authors pointed out a need to validate the current findings in multiple studies.