Which combination of factors are among the two most important prognostic factors for malignant melanoma?

• A. Depth of invasion and Size of lesion
• B. Depth of invasion and Color of lesion
• C. Size of lesion and Border irregularity
• D. Color of lesion and Border irregularity

Answer: (A)

The key idea is that prognosis in melanoma is driven by how much the tumor has invaded and how much tumor burden there is. The depth of invasion, often measured as Breslow thickness, is the strongest predictor of metastatic risk and survival—the deeper the tumor penetrates into the skin, the higher the likelihood of spread and the worse the outlook. The size of the lesion adds prognostic information because a larger diameter typically indicates a longer time to grow and an increased chance the tumor has extended deeper or shed malignant cells, translating into a higher risk of adverse outcomes. Together, these two factors provide the most powerful clues about prognosis among the options listed. Other features like color or border irregularity are important for diagnosis, not as reliable on their own for predicting outcome, and while ulceration and mitotic rate also matter, depth and size are the primary prognostic indicators highlighted here.