I am so sorry that this has happened to your daughter. To me it is a circumstance created by our truly horrible medical system. When diagnosed with stage 1 malignant melanoma in 2019, I was in a tailspin: cardiac issues and diabetes are what historically take my people down, not cancer.
My doctor told me in a cautioning voice that in years past, a patient like myself would receive an annual PET for just the reasons you indicate. Insurers, however, decided it was too costly (TO THEIR BOTTOM LINE) to continue this preventative diagnostic measure.

I have had many biopsies, squamous and basal cells treated, more spots frozen than I could count in the intervening years since 2019 and see the dermatologist every quarter. As a patient waiting for the other shoe to drop, I never ignore anything unusual in or on my body. I've had toenails removed at my doctor's advice because spots appeared on my nail bed under the nails. When digestive issues present, I'm quick to see my primary doctor who is sympathetic and proactive, repeatedly calling malignant melanoma 'the great imposter' due to its ability to mask as an ailment other than cancer.

Today, as a 75 yo woman experiencing the slings and arrows of aging, my doctor visits are ever-increasing, leaving me wondering if my insurers are in fact contributing to their bottom line by refusing to allow the former standard of care for patients with known malignant melanoma. Is my new right leg pain arthritis or bone cancer? Are my GI distresses routine or colon cancer? In addition, there's the constant worry of what may be brewing in my body that hasn't yet manifested in any detectable way. Once malignant melanoma is diagnosed, at any stage, it's a waiting game. Not a good one.

I'm fortunate - and grateful - to have Medicare and a good supplemental plan but not all people are in my situation. And yet, even with the insurers I have, current standard of care has denied me and many, many others access to best medical practices.