Skin Cancer 高雄長庚醫院放射腫瘤科 許軒之

Skin cancer Basal cell carcinoma Squamous cell carcinoma Melanoma

Comparison

Risk factors(1) Sun damage: the incidence in blacks is much lower than in whites Arsenic exposure:BCC, SCC Irradiation: 2/3 of these cancers are BCC and 1/3 are SCC Coal tar: SCC Immunosuppression: renal transplantation, increased incidence of SCC

Risk factors(2) Chronic inflammation and trauma Hereditary factors Infection: HPV Oncogene

Diagnosis Skin biopsy is necessary to confirm the clinical suspicion of skin cancer

Staging system Basal cell carcinoma rarely metastasizes, and thus a metastatic work-up is usually not necessary. Regional lymph nodes should be routinely examined in all cases of squamous cell carcinoma The TNM (primary tumor, nodal involvement, and metastasis) classification is used to stage both basal cell carcinoma and squamous cell carcinoma.

Basal cell carcinoma(1) Basal cell carcinoma is at least 3 times more common than squamous cell carcinoma in nonimmunocompromised patients. It usually occurs on sun exposed areas of skin, and the nose is the most frequent site. the most characteristic type is the asymptomatic nodular or nodular ulcerative lesion that is elevated from the surrounding skin and has a pearly quality and contains telangiectatic vessels. It is recognized that basal cell carcinoma has a tendency to be locally destructive.

Basal cell carcinoma(2) High-risk areas for tumor recurrence include the central face (periorbital region, eyelids, nasolabial fold, nose-cheek angle), postauricular region, pinna, ear canal, forehead, and scalp. A specific subtype of basal cell carcinoma is the morphea-form type. It typically appears as a scar-like, firm plaque and because of indistinct clinical tumor margins, it is difficult to treat adequately with traditional treatments.1

Squamous cell carcinoma(1) Squamous cell tumors also tend to occur on sun-exposed portions of the skin such as the ears, lower lip, and dorsa of the hand. However, squamous cell carcinomas that arise in areas of non-sun-exposed skin is prognostically worse since they have a greater tendency to metastasize.

Squamous cell carcinoma(2) Chronic sun damage, sites of prior burns, arsenic exposure, chronic cutaneous inflammation as seen in long standing skin ulcers, and sites of previous x-ray therapy are predisposed to the development of squamous cell carcinoma.

Treatment Traditional surgical resection: require adequate margin Mohs’ micrographic surgery Radiotherapy

Melanoma(1) Melanoma is a malignant tumor of melanocytes, cells that are derived from the neural crest. Although most melanomas arise in the skin, they may also arise from mucosal surfaces or at other sites to which neural crest cells migrate.

Melanoma(2) Early signs in a nevus that would suggest malignant change include darker or variable discoloration, itching, an increase in size, or the development of satellites. Ulceration or bleeding are later signs. For disease clinically confined to the primary site, the greater the thickness and depth of local invasion of the melanoma, the higher the chance of lymph node metastases and the worse the prognosis.

Melanoma(3) Melanoma can spread by local extension (through lymphatics) and/or by hematogenous routes to distant sites. Any organ may be involved by metastases, but lungs and liver are common sites.

Soft Tissue Sarcoma

Definition Primary mesenchymal tumors localized outside the skeleton, parenchymatous organs, or hollow viscera are generally designated as soft tissue sarcoma. Soft tissue sarcomas are malignant tumors that may arise in any of the mesodermal tissues of the extremities (50%), trunk and retroperitoneum (40%), or the head and neck (10%).

Pathology(by site of origin) Head and Neck Rhabdomyosarcoma (child) Angiosarcoma (elderly person) Osteogenic sarcoma(jaw) Distal extremity Epithelioid sarcoma Synovial sarcoma Clear cell sarcoma Osteogenic sarcoma (femur)

Pathology Proximal tibia or humerus Methothelium Osteogenic sarcoma Methothelium Methothelioma Retroperitoneum and mesentery Leiomyosarcoma Liposarcoma Malignant fibrous histiocytoma

Pathology Genitourinary tract Skin Rhabdomyosarcoma (in a child) Leiomyosarcoma (in an adult) Skin Angiosarcoma, lymphangiosarcoma Kaposi’s sarcoma Epithelioid sarcoma Dermatofibrosarcoma protuberans

STS(1) These tumors may be heterogeneous, thus adequate tissue should be obtained via either core needle or incisional biopsy for microscopic examination to determine histologic type and tumor grade. In most cases, the radical surgical procedures of the past have given way to a combined modality approach: pre- or postoperative radiation therapy. The role of chemotherapy is less well defined.

STS(2) The prognosis for patients with adult soft tissue sarcomas depends on several factors, including the patient's age and the size, histologic grade, and stage of the tumor. (Older than 60 years of age, tumors larger than 5 centimeters, or high-grade histology are associated with a poorer prognosis). higher grade sarcomas (as determined by the mitotic index and the presence of hemorrhage and necrosis) are associated with higher local treatment failure rates and increased metastatic potential.

STS(3) When feasible, wide margin function-sparing surgical excision is the cornerstone of effective treatment. (Mohs surgical technique may be considered as an alternative to wide surgical excision for small, well-differentiated sarcomas when cosmetic results are considered to be very important, as margins can be assured with minimal normal tissue removal).

STS(4) High-grade soft tissue sarcomas of the extremities can often be effectively treated while preserving the limb with combined modality treatment consisting of preoperative or postoperative radiation therapy. In adults, local control of high-grade soft tissue sarcomas of the trunk and the head and neck can be achieved with surgery, often in combination with radiation therapy with or without chemotherapy.

STS(5) Effective treatment of retroperitoneal sarcomas requires removal of all gross disease while sparing adjacent viscera not invaded by tumor. The prognosis for high-grade retroperitoneal sarcomas is less favorable than for other sites, partly because of the difficulty in completely resecting these tumors and the limitations placed on high-dose radiation therapy.

STS(6) Several prospective randomized trials have been unable to confirm conclusively whether doxorubicin-based adjuvant chemotherapy benefits adults with resectable soft tissue sarcomas. The majority of these studies accrued small numbers of patients and did not demonstrate a metastasis-free or an overall survival benefit for adjuvant chemotherapy. Patients with high-grade tumors (grades 3 or 4) greater than 5 centimeters in diameter have the greatest tendency for disease to metastasize and are eligible for prospective clinical trials of adjuvant chemotherapy.