Revised 11 January 2013
Small Lesions Less than 0.5 cm in Diameter
Small basal cell carcinomas are best treated by surgical excision with a minimum 4 mm margin in all directions, or by curettage and electro-fulguration. It is important to assess and mark the margins under good light, prior to the infiltration of local anesthetic. Lesions with ill-defined edges, particularly on the face, may be best treated by radiation therapy or by Mohs micrographic surgery and this can be arranged by referral to the Skin Management Clinic. The inner canthus, nasolabial groove, paranasal skin, and postauricular skin have a high incidence of local recurrence and should not be treated with electro-fulguration and curettage except in certain cases. Recurrent tumours at these sites can be assessed by the Skin Management Clinic. The more common small nodular lesions that have been completely excised, as verified by a pathologist, do not require referral to the Agency.
Lesions 0.5 to 2.0 cm in Diameter (minimum 5 mm margin)
Most patients with these lesions will be referred to a dermatologist, a surgeon or to the Skin Management Clinic of the BCCA. Depending upon the clinical circumstances of each patient, treatment may be curettage and electro-fulguration, excision with primary closure, including Mohs micrographic surgery, or radiation therapy; or if on the face and ill-defined, Mohs micrographic surgery. If excision will cause significant cosmetic deformity, or in older patients, radiation therapy may be the preferred treatment. No referral to the Skin Management Clinic is necessary, if there has been a complete excision verified by a pathologist.
Large Lesions by Virtue of Area or Degree of Infiltration (minimum 5 mm margin)
Patients with these lesions are often best referred for specialist opinion or to the Skin Management Clinic. Treatment may be by radiation therapy, standard surgery, including a wide excision and flap repair or skin graft, or micrographic surgery. Great care must be taken to determine the extent of the lesion prior to undertaking surgery. If excision will cause significant cosmetic deformity, radiation therapy may be the preferred treatment. A surgeon may find it advisable to obtain a pathologist's opinion during surgery with regard to completeness of removal. Tumours that are ill-defined or recurrent after surgery are often best treated with radiation therapy or Mohs micrographic surgery (see 6.4.9). Micrographic surgery may also be considered for lesions recurrent after radiation therapy.
Superficial Basal Cell Carcinoma on the Trunk and Limbs
Below the knee radiation therapy is avoided when possible. Due to the high dose of radiation required and the usually poor blood supply in elderly patients, post treatment ulceration can take many months to heal. The tumour can be treated by surgical excision or curettage and electrofulguration.
Recurrent Basal Cell Carcinomas
If the cancer is recurrent, consider changing therapeutic modality to treat the recurrence e.g., if recurrence after surgery, consider radiation therapy and vice versa.
Incompletely Excised Basal Cell Carcinomas
While histologically incompletely excised basal cell carcinomas are sometimes observed, those with a morpheic, spindling pattern should always be treated to histologic cure. These lesions have a very high recurrence rate unless aggressively treated by micrographic surgery, radiation therapy or wide simple surgery.
Morpheic Basal Cell Carcinoma
(Synonym: Sclerosing, Spindling, Infiltrating)
Morpheic basal cell carcinomas require excision with wider margins up to a centimeter. Consideration should be given to micrographic surgery.
Topical 5-fluorouracil Therapy
Topical 5-fluorouracil therapy, while appropriate for actinic keratosis, is not appropriate therapy for basal cell carcinomas because of a very low cure rate, and the possibility of subclinical spread.
Interferon is an alternate form of treatment for selected types of Basal Cell and Squamous Cell Carcinomas in patients where surgery and radiation therapy are contraindicated.