External irradiation of epithelial skin cancer

Abstract

A total of 339 consecutively treated, biopsy proven squamous and basal cell carcinomas of the skin treated from January 1966 to December 1986 were retrospectively analyzed to determine the patterns of local recurrence. There were 242 basal cell carcinomas, 92 squamous cell carcinomas, and 5 variants of squamous cell carcinoma in various locations. Radiotherapy was the initial treatment modality in 212 patients and 127 were treated after failing initial surgical excision. Lymph nodes were involved in 1 242 patients (.4%) with basal cell carcinoma, 14 92 patients (15%) with initially treated squamous cell carcinoma, and 20 51 (39%) with recurrent squamous cell lesions. Distant metastasis was found in one patient. Superficial X rays were given to 187 patients, electrons to 57 patients, megavoltage photons to 15, and a combination of modalities to the remainder. Overall local tumor control was achieved in 292 of 339 patients (86%), 220 of 242 (91%) with basal cell and 73 of 97 (75%) with squamous cell carcinoma. Tumor control was closely related to the size of the primary lesion. For lesions < 1 cm tumor control was 97% ( 86 89 ) for basal cell and 91% ( 21 23 ) for squamous cell carcinoma. For 1 to 5 cm, tumor control was 87% ( 116 133 ) for basal cell and 76% ( 39 51 ) for squamous cell carcinoma and for lesions greater than 5 cm, the tumor control was 87% (13 of 15) and 56% ( 9 16 ), respectively. Tumor control was related to the modality used to treat the patient in spite of stratification of primary lesion size. For superficial X rays, tumor control was 98% ( 81 83 ) for lesions < 1 cm, 93% ( 94 101 ) for lesions 1–5 cm and 100% ( 5 5 ) for lesions greater than 5 cm. For electrons tumor control was 88% ( 14 16 ), 72% ( 23 32 ), and 78% ( 7 9 ), respectively. For mixed beams tumor control was 90% ( 9 10 ), 76% ( 32 42 ), and 64% ( 9 14 ), respectively, and for 60Co-4 MV X rays, tumor control was 100% ( 3 3 ), 67% ( 6 9 ), and 33% ( 1 3 ), respectively. Cosmesis and complications were analyzed in 261 patients. An excellent or good cosmetic result was found in 92% ( 239 261 ) of the patients. There were 8 of 261 patients (3.1%) with fair and 19 of 261 (7.3%) with poor cosmesis. Cosmesis had an inverse relation to the primary lesion size with 97 of 99 patients (98%) with tumors 1 cm or less, 123 of 140 patients (88%) with lesions 1 to 5 cm and 13 of 16 patients (82%) with larger tumors having excellent or good cosmetic results. Cosmesis is also related to treatment modality. Excellent or good cosmesis was seen in 161 of 169 patients (95%) with superficial X rays, 37 of 46 patients (80%) with electrons, 39 of 51 patients (76%) with mixed beams, and 7 of 10 patients (70%) with megavoltage photons. The overall complication rate was 5.5% ( 17 310 ); this was directly related to the primary tumor size. For lesions 1 cm or less, the complication rate was 0.9% ( 1 108 ), for lesions 1 to 5 cm 7.1% ( 12 169 ), and for lesions > 5 cm 13.6% ( 3 22 ). Undoubtedly, this is related to larger volumes and higher irradiation dose used to treat them. We conclude that radiotherapy is an excellent treatment modality for epithelial skin cancer. Local tumor control, cosmesis, and complications are related to size of the primary lesion and thus treatment at an early stage is strongly recommended. Since tumor control and cosmesis also correlated with technical factors, careful attention to radiotherapy technique is required.