DEAR DR. ROACH: I was recently diagnosed with superficial spreading melanoma. I had a wide excision and was told to follow up with a dermatologist. The dermatologist says to follow up every six months; is this frequent enough? It was found during a routine annual skin check, and I never expected this outcome.

I am amazed at the number of people I have encountered since who have had one or more melanoma excisions. How important is sunscreen for melanoma? I am told that it can recur anywhere anytime; does this mean as a skin lesion or internally as well?

I was told by a doctor to have my genital and rectal areas checked routinely as well. Is this something dermatologists do regularly, or do they defer this to gynecologists or primary care physicians? At what point might a medical oncologist get involved? Finally, why do they not use scanning as a tool during these early findings? — F.W.L.

ANSWER: Melanoma is not the most common skin cancer, but it’s by far the most dangerous. Although there have been dramatic improvements in the care of melanoma, preventing it is still the best option, with the second choice being to catch early before it has a chance to spread.

Since ultraviolet light is the main risk factor for melanoma, avoidance is the key. Staying out of the sun, using sun-protective clothing, and applying sunscreen are all effective. I recommend a broad-spectrum (UVA and UVB) sunscreen with an SPF of at least 30.

Higher numbers are more effective, with SPF 100 being more effective than SPF 50, contrary to some advice that I have read. What’s more important than the SPF number is applying it early, liberally (a full ounce for an average-sized person), and repeatedly, especially when in and out of water. Tanning machines should never be used.

Once a person has melanoma, then prevention becomes even more important. A total skin exam, including the genitals and buttocks, should be done by an expert, which usually means a dermatologist, although primary care doctors and gynecologists should also look out for melanoma. The total skin exam is done to look for a new cancer. Dermatologists often use a dermatoscope, which provides lighting and magnification and requires training to use.

Melanoma can spread to the internal organs. The deeper the melanoma, the more likely it is to spread. Superficial spreading melanoma, the kind you have, is the least likely to spread. CT or MRI scanning might be used if there is a suspicion that the melanoma has spread. However, they still aren’t as good as a trained clinician at finding skin lesions. New technology, including AI, may improve the ability to screen for melanoma. A medical oncologist is an appropriate expert for any distant disease.

Self-exams are important as well. The ABCDE rule remains useful: Any mole with Asymmetry; irregular Borders; Color variation within the mole; a Diameter greater than 6 mm (a standard pencil eraser); or Evolution over time should be referred to a dermatologist.

Also, an “ugly duckling,” which is different from other lesions, should be referred, as should any lesions under the nail or any lesions that bleed or itch.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu. (c) 2026 North America Syndicate Inc. All Rights Reserved