Melanoma


 * Epidemiology: || Accounts for 1.5% of all skin cancers. Occurs most frequently in white adults (more rarely seen in dark-skinned ethnicities). Equal incidence in men and women. Peak incidence occurs during 4th and 5th decades of life. 1 ||
 * Etiology: || The greatest risk of sun exposure-induced melanoma is associated with acute, intense and intermittent blistering sunburns. This risk is different than that of squamous and basal cell skin cancers, which are associated with prolonged, long-term sun exposure.

Causes may include the following: -Exposure to ultraviolet radiation (UVR) - both UVA and UVB potentially are carcinogenic and actually may work in concert to induce a melanoma. -Chemical and viral exposure are 2 etiologic agents that also have been implicated in the development of melanoma.

Greatly elevated risk factors for cutaneous melanoma: -changing mole -dysplastic nevi in familial melanoma -greater than 50 nevi, 2 mm or greater in diameter

Moderately elevated risk factors for cutaneous melanoma: -one family member with melanoma -previous history of melanoma -sporadic dysplastic nevi -congenital nevus

Slightly elevated risk factors for cutaneous melanoma: -immunosuppression -sun sensitivity -history of acute, severe, blistering sunburns -freckling 2 || __Superficial spreading melanomas (SSM)__ - approximately 70% of cutaneous melanomas; typical changes include ulceration, enlargement or color changes; a SSM may be found on any body surface, especially the head, neck, and trunk of males and lower extremeities of females. __Nodular melanomas__ - 10-15% of melanomas; are commonly found on all body surfaces, especially the trunk of males; these lesions are the most symmetrical and uniform of the melanomas and are dark brown or black in color. __Lentigo maligna melanomas (LMMs)__ - 10-15% of melanomas; typically found on sun exposed areas of the body; LMMs may have areas of hypopigmentation and are often quuite large. __Acral lentiginous melanomas__ - they occur on the palms, soles and subungual areas. __Mucosal lentiginous melanomas__ - may occur on any mucosal surface, including conjunctiva, oral cavity, esophagus, vagina, female urethra, penis and anus.
 * Signs & Symptoms: || Clinical presentation of melanoma varies by type:

The majority of melanomas are in the skin but other sites include the eyes, mucosa, gastrointestinal tract, genitourinary tract and leptomeninges. 2 || -Physical examination should focus on appreciation of changes in the normal appearance of the skin. -The size, diameter, depth of invasion and mulitfocality of the tumor must be precisely defined. -Regional lymph nodes must be assessed. -Various tools to assess the skin, including Wood's light and potassium hydroxide preparations, fungal cultures, skin biopsies, Tzanck smears and patch testing should be used. 1
 * Diagnostic Procedures: || -The diagnosis of skin cancer requires a detailed clinical history.

A total-body skin examination is crucial when evaluating a patient with an atypical nevus or a melanoma. Crucial to a good examination is a well-lit examining room and a completely disrobed patient. Serial photography and new techniques, such as epiluminescence microscopy and computerized image analysis, are useful adjuncts.

The ABCDs for differentiating early melanomas from benign nevi include the following: A: Asymmetry (melanoma lesion more likely to be asymmetric) B: Border irregularity (melanoma more likely to have irregular borders) C: Color (melanoma more likely to be very dark black or blue and have variation in color than a benign mole which is more often uniform in color and light tan or brown) D: Diameter (mole < 6 mm in diameter usually benign)

Total workup for melanoma to include: -CBC count -Chemistry panel (complete) -Lactate dehydrogenase (LDH) -Chest xray -CT or MR of the brain -CT of the chest, abdomen, pelvis -PET scan -Biopsy of suggestive lesion -Surgical excision or reexcision after biopsy -Elective lymph node dissection -Sentinel lymph node dissection 2 || || If grouped according to stage for localized primary melanoma, the overall survival rate is 80%. For patients with regional lymph node metastases (stage III disease), survival rates were 27% to 69% at 5 years and 18% to 63% at 10 years. Unfortunately, when there is evidence of distant metastases (stage IV disease), the 5-year survival rate is only 9% to 19%, and the 10-year survival rate is 6% to 16%. However, spontaneous regression has been documented in melanoma, even in patients with metastatic disease. 4 || Surgery to remove area and Radiation Therapy 60 to 70 Gy in 2 to 3 fractions. 1 1 to 2 cm boarders. ||
 * Histology: || The four major subtypes of melanoma are: superficial spreading, nodular, lentigo maligna, and acral lentiginous. ||
 * Lymph Node Drainage: || All lymph node groups should be examined upon a melanoma diagnosis. Melanomas can disseminate via the lymphatics, leading to involvement of regional lymph nodes and hematogenously, leading to involvement of any node basin in the body. 2 ||
 * Metastatic Spread: || Melanomas can metastasize to lymph nodes or all other visceral organs in the body. 2 ||
 * Grading: || [[image:melanomagrade1.jpg width="412" height="222"]] ||
 * Staging: || Melanoma uses the TNM staging. “The primary difference between the definitions of clinical and pathologic stage grouping is whether the regional lymph nodes are staged by clinical/radiologic exam or by pathological exam (after partial or complete lymphadenectomy). 3
 * Radiation Side Effects: || Side effects may include erythema, skin irritation, dry desquamation, moist desquamation, and fatigue. 4 ||
 * Prognosis: || # Melanoma in situ: 100% survival at 5 years and 10 years
 * 1) Lesions ≤1 mm: 91%-95% at 5 years; 83%-88% at 10 years
 * 2) Lesions 1.01-2 mm: 77%-89% at 5 years; 64%-79% at 10 years
 * 3) Lesions 2.01-4 mm: 63%-79% at 5 years; 51%-64% at 10 years
 * 4) Lesions >4 mm: 45%-67% at 5 years; 32%-54% at 10 years
 * Treatments: || Surgery and Radiation Therapy
 * TD5/5: || The TD5/5 for skin is 15-20Gy for single dose and 30-40Gy for fractional dose. 1 ||
 * Planning Photos || [[image:melanoma2.jpg width="275" height="203"]]

Photos of melanoma. 5 || **References** 1. Chao KS, Perez CA, Brady LW. //Radiation Oncology - Management Decisions. // <span style="font-family: Arial,Helvetica,sans-serif;"> 2nd ed. Philadelphia: Lippincott, Williams & Wilkins, 2002: 111-122. 2. eMedicine. Malignant Melanoma. []. Accessed February 11, 2010. 3. Gunderson and Tepper. Clinical Radiation Oncology. 2nd Edition. Philadelphia, PA: Churchill Livingstone. 2007. 4. Cleveland Clinic. [] Accessed February 21, 2010. 5. A.D.A.M. [] Accessed February 21, 2010.