Chapter 083. Cancer of the Skin (Part 3)

Prognostic FactorsThe most important prognostic factor is the stage at the time of presentation. Fortunately, most melanomas are diagnosed in clinical stages I and II. The revised American Joint Committee on Cancer (AJCC) staging system for melanoma is based on microscopic primary tumor depth (Breslows thickness), presence of ulceration, evidence of nodal involvement, and presence of metastatic disease to internal sites (Table 83-3). Certain anatomic sites may affect the prognosis. The favorable sites appear to be the forearm and leg (excluding feet), while unfavorable sites include scalp, hands, feet, and mucous membranes. In general, women with stage I or...
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Chapter 083. Cancer of the Skin (Part 3) Chapter 083. Cancer of the Skin (Part 3) Prognostic Factors The most important prognostic factor is the stage at the time ofpresentation. Fortunately, most melanomas are diagnosed in clinical stages I andII. The revised American Joint Committee on Cancer (AJCC) staging system formelanoma is based on microscopic primary tumor depth (Breslows thickness),presence of ulceration, evidence of nodal involvement, and presence of metastaticdisease to internal sites (Table 83-3). Certain anatomic sites may affect theprognosis. The favorable sites appear to be the forearm and leg (excluding feet),while unfavorable sites include scalp, hands, feet, and mucous membranes. Ingeneral, women with stage I or II disease have a better survival than men, perhapsin part because of earlier diagnosis; women frequently have melanomas on thelower leg, where self-recognition is more likely and prognosis is better. Olderindividuals, especially men over 60, have poorer prognoses. This finding has beenexplained in part by a tendency toward later diagnosis (and thus thicker tumors) inmen and by a higher proportion in men of acral melanomas (palmar-plantar),which have a poorer prognosis. Melanoma may recur after many years. About 10–15% of first-time recurrences develop >5 years after treatment of the originallesion. The time to recurrence varies inversely with tumor thickness. Analternative prognostic scheme for clinical stages I and II melanoma, proposed byClark, is based on the anatomic level of invasion in the skin. Level I isintraepidermal (in situ); level II penetrates the papillarydermis; level III spans thepapillary dermis; level IV penetrates the reticular dermis; and level V penetratesinto the subcutaneous fat. The 5-year survival for these stages averages 100, 95,82, 71, and 49%, respectively. Table 83-3 Prognosis of Melanoma by Thickness (Breslow) andRevised AJCC Stages: 5-Year Survival Rates AJCC Thickness, Ulceration Nodal DistantStage mm Disease Metastases 0 In situ N/A No No IA IB 4.0 No No NoIIC >4.0 Yes No NoIIIA Any No Yes 1 node No w/microscopic disease 2–3 No nodes w/microscopic diseaseIIIB Any Yes 1 node No w/microscopic disease Any Yes 2–3 No nodes w/microscopic disease Any No 1 node No w/macroscopic disease Any No 2–3 No nodes w/macroscopic disease Any Any In transit No or satellite disease w/out nodal diseaseIIIC Any Yes 1 node No w/macroscopic disease Yes 2–3 No nodes w/macroscopic disease Any ≥4 No metastatic or matted nodes, or in transit mets/satellites or metastatic nodes IV Any Any Any Yes Note: AJCC, American Joint Commission for Cancer. Natural History Melanomas may spread by the lymphatic channels or the bloodstream. Theearliest metastases are often to regional lymph nodes. Lymphadenectomy maycontrol early regional disease. Liver, lung, bone, and brain are common sites ofhematogenous spread, but unusual sites, such as the anterior chamber of the eye,may also be involved. Once metastatic disease is established, cure is unlikely.