Final answer:
The prognosis of a patient with malignant melanoma is most dependent on the thickness of the lesion, as it indicates the potential for the cancer to have spread to other parts of the body.
Step-by-step explanation:
When teaching a patient with malignant melanoma about this disorder, it's important to understand that the prognosis of the patient is most dependent on the thickness of the lesion. This is because the depth of invasion or thickness of the melanoma, most often measured in millimeters, is strongly correlated with the risk of the cancer spreading, or metastasizing. The thicker the melanoma, the more likely it is to spread to other parts of the body, which can worsen a patient's prognosis.
Malignant melanoma is the most deadly form of skin cancer due to its ability to metastasize rapidly. Using the ABCDE mnemonic - Asymmetry, Borders, Color, Diameter, Evolving - can help in the early detection of melanomas. However, when considering the actual prognosis, other factors such as degree of color change, superficial spread, and ulceration are secondary to lesion thickness.