I read on https://www.accessdata.fda.gov/drugsatfda_docs/label/2004/20723s016lbl.pdf (mirror):
364 patients with primary superficial basal cell carcinoma (sBCC) were treated with Aldara Cream or vehicle cream 5X/week for 6 weeks. Patients with one biopsy-confirmed sBCC tumor were enrolled and randomized in a 1:1 ratio to active or vehicle treatment. Target tumors were to have a minimum area of 0.5 cm2 -and a maximum diameter of 2.0 cm (4.0 cm2 ). Target tumors were not to be located within 1.0 cm of the hairline, eyes, nose, mouth, ears, on the anogenital area or on the hands or feet, or have any atypical features. On a scheduled dosing day, the study cream was applied to the target tumor and approximately 1 cm (about 1/3 inch) beyond the target tumor prior to normal sleeping hours; 5X/week dosing was continued for a total of 6 weeks.
Should Imiquimod 5% cream (US brand: Aldara) be applied 1 cm beyond the target tumor when treating a facial basal cell carcinoma (BCC), and if so, why?
1 cm sounds quite large to me when the tumor is less than 1cm².