Histologic subtype of treatment failures after noninvasive therapy for superficial basal cell carcinoma: An observational study

• Published in: Journal of the American Academy of Dermatology 2019-04, Vol.80 (4), p.1022-1028
• Main Authors: van Delft, Lieke C.J., Nelemans, Patty J., Jansen, Maud H.E., Arits, Aimee H.M.M., Roozeboom, Marieke H., Hamid, Myrurgia A., Mosterd, Klara, Kelleners-Smeets, Nicole W.J.
• Format: Article
• Language: English
• Subjects: 5-fluorouracil; Aged; Aminolevulinic Acid - analogs & derivatives; Aminolevulinic Acid - therapeutic use; Antimetabolites, Antineoplastic - therapeutic use; Antineoplastic Agents - therapeutic use; basal cell carcinoma; Carcinoma, Basal Cell - drug therapy; Carcinoma, Basal Cell - pathology; Equivalence Trials as Topic; Female; Fluorouracil - therapeutic use; histologic subtype; Humans; imiquimod; Imiquimod - therapeutic use; MAL-PDT; Male; Middle Aged; misclassification; noninvasive therapy; Photochemotherapy; Photosensitizing Agents - therapeutic use; sampling error; Skin Neoplasms - drug therapy; Skin Neoplasms - pathology; superficial; transformation; Treatment Failure
• ISSN: 0190-9622; 1097-6787
• DOI: 10.1016/j.jaad.2018.12.028

There have been concerns that recurrences after noninvasive therapy for basal cell carcinoma (BCC) transform into a “more aggressive” histologic subtype. We sought to evaluate the proportion of patients with a nonsuperficial treatment failure after noninvasive therapy for superficial BCC. An observational study was performed using data from a single blind, noninferiority, randomized controlled trial (March 2008-August 2010) with 5-year follow-up in patients with primary superficial BCC treated with methylaminolevulinate–photodynamic therapy, 5-fluorouracil, or imiquimod. Data were used from 166 adults with a histologically confirmed treatment failure. A nonsuperficial 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 = .003). The proportion of more aggressive early failures was significantly lower after imiquimod (26.3%) compared with methylaminolevulinate–photodynamic therapy (54.8%, P = .086) and 5-fluorouracil (66.7%, P = .011). There was limited information on the exact time of occurrence of treatment failures. More aggressive treatment failure recurrences after noninvasive therapy for superficial BCC occur most often within the first 3 months posttreatment, probably indicating underdiagnosis of more aggressive components in the primary tumor rather than transformation.