Author: Vanessa Ngan, Staff Writer; Copy Editor: Clare Morrison; Chief Editor: Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand, October 2013. About Melanoma is sponsored by the New Zealand Dermatological Society Incorporated.
Thin melanoma or melanoma in situ is not dangerous. Melanoma only becomes life-threatening if it grows deeper into the layers of skin and spreads to other parts of the body. The risk of spread and eventual death from metastatic melanoma depends on several factors but the main one is how thick the first melanoma is at the time it was surgically removed.
Melanoma less than 0.75mm thick rarely spreads or metastasises, whereas melanoma 0.75–1 mm thick has about 5% chance of metastasis. The risk of metastases steadily rises with thickness so that melanoma more than 4mm thick have about 40% chance of spreading.
Getting a second melanoma does not mean a poor outcome, especially if it is picked up in its early stages. In many cases, a second melanoma picked up early is thinner than the first one. If melanoma is picked up in its early stages it can be easily and successfully removed, with over 90% of people making a full recovery.