Histological subtype of treatment failures after noninvasive therapy for superficial basal-cell carcinoma: an observational study

Publication date: Available online 21 December 2018

Source: Journal of the American Academy of Dermatology

Author(s): Lieke C.J. van Delft, Patty J. Nelemans, Maud H.E. Jansen, Aimee H.M.M. Arits, Marieke H. Roozeboom, Myrurgia A. Hamid, Klara Mosterd, Nicole W.J. Kelleners-Smeets

Abstract

Background

There have been concerns that recurrences after noninvasive therapy for basal-cell carcinoma (BCC) transform into a 'more aggressive' histological subtype.

Objective

To evaluate the proportion of patients with a non-superficial treatment failure after noninvasive therapy for superficial BCC.

Methods

An observational study was performed using data from a single blind, non-inferiority, randomized controlled trial (March 2008-August 2010) with five year follow-up in patients with primary superficial BCC treated with methylaminolevulinate-photodynamic therapy (MAL-PDT), 5-fluorouracil or imiquimod. Data were used from 166 adults with a histologically confirmed treatment failure.

Results

A non-superficial subtype was found in 64 of 166 treatment failures (38.6%). Proportions with a 'more aggressive' subtype than the primary tumor were 51.3% (38/74) for early and 28.3% (26/92) for later treatment failures (p=0.003). The proportion of 'more aggressive' early failures was significantly lower following imiquimod (26.3%) compared to MAL-PDT (54.8%, p=0.086) and 5-fluorouracil (66.7%, p=0.011).

Limitations

There was limited information on the exact time of occurrence of treatment failures.

Conclusion

'More aggressive' treatment failures after noninvasive therapy for superficial BCC occur most often within the first three months post-treatment probably indicating underdiagnosis of 'more aggressive' components in the primary tumor rather than transformation.

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