Post Irradiation Scalp Malignancy

Post irradiation scalp malignancy usually occurs in patients who had balding lesions in childhood that did not respond to antifungal drugs. Pigmented lesions and senile keratosis will appear about 20 years after radiotherapy. They can develop into basal cell carcinoma and rarely to squamous cell carcinoma, which are mostly multicentric. If there is any delay in treatment, those lesions can be invasive and involve even the dura mater. The objective of this study was to assess the best treatment for these lesions.

Thirty–six patients were studied, with an age range of 55–70 years. They had undergone radiotherapy about 20–40 years before entering the study. Tests were performed to determine the exact extent of lesions, and the condition of skin, bone and dura mater, including local biopsy and CT scan. Patients who had multicentric lesions without involvement of the skull (category A) were treated by total excision of the scalp and skin grafting; a more major operation was performed for those who had involvement of the skull, with or without dura mater involvement (category B).

Nine patients were in category A; all the suspect skin was excised, and the recipient sites then covered by split–thickness skin graft. A 10-year follow–up of these patients revealed no recurrence. Twenty–seven patients were in category B; they underwent major surgery: total excision, removal of all suspect tissues, and a conventional free flap transfer, latissmus dorsi with or without serratus anterior and ribs.

For patients who had no skull involvement, total excision of the skin and coverage of the recipient site with split–thickness skin graft was advised. Because of possible development of malignancy, multiple excisions and approximation at the sites was not recommended. For patients with involvement of the skull or dura mater, removal of the suspect tissues, such as scalp, skull, and sometimes dura mater itself was advised, and transfer of a conventional free flap: latissmus dorsi with or without serratus anterior and ribs. Anastomosis should be performed exactly. The recipient vessels must be reliable; if not, necrosis of the flap, exposure of living tissue, and further complications may ensue.