[Squamous cell carcinoma].

Abstract

Squamous cell carcinoma of the skin is common skin malignancy arising from malignant proliferation of the keratinocytes of the epidermis. Chronic exposure to ultraviolet radiation in sunlight is the most important risk factor for squamous cell carcinoma. Early diagnosis and appropriate treatment provide the best opportunity to cure cutaneous squamous cell carcinomas. Although it is locally invasive, squamous cell carcinomas usually remain localized and can be cured by a variety of techniques. Surgical excision is the most broadly used treatment for high-risk squamous cell carcinoma. It is well-tolerated, extremely effective, and the completeness of the procedure can be evaluated through histologic assessment of the specimen's margins. About 10 percent of squamous cell carcinomas in Japan spread to regional lymph nodes or more distant sites with a relatively poor outcome. Five-year cure rates are reported to be 85 to 80 percent for Japanese patients with squamous cell carcinomas, respectively. Recommendations for surgical margins vary depending upon the risk of local recurrence, especially; squamous cell carcinomas with perineural extension also need more extensive procedures. Patients with clinically enlarged lymph nodes may require radiographic imaging, fine needle aspiration, or lymph node biopsy. Depending upon the results of these tests, regional lymph node dissection may be done. Recently the sentinel lymph node biopsy technique is being evaluated for its ability to detect microscopic involvement in patients with high-risk patients who have no clinical evidence of lymph node metastasis. The occurrence of regional lymph node metastases places the patient at increased risk for the subsequent development of distant metastases. Distant metastases are associated with a markedly increased risk of disease-related mortality. Systemic chemotherapy has been to limited benefit in patients with disseminated squamous cell carcinoma patients. In Japanese patients with distant metastases, the five-year survival rate is about 10 percent. The ability of current chemotherapy protocols to increase the cure ratio in squamous cell carcinoma is still controversial.