Melanoma: A Pathologist’s Perspective
With summer upon us it is time to think about sun safety. An alarming recent report found rates of new melanoma have doubled over the past three decades. It is estimated that education and awareness of the dangers could prevent 20 percent of new cases between 2020 and 2030, according to the CDC report. Without prevention programs rates will continue to increase.
Melanoma Facts
Skin cancer is the number one cancer in the US. Over 9,000 Americans die each year due to melanoma. In 2011 there were more than 65,000 new cases. UV radiation from the sun or tanning beds accounts for 90% of cases. Risk doubles if an individual has had five or more sunburns, or one blistering sunburn at a young age. Other risk factors include fair skin, numerous moles, a family history of unusual moles or melanoma.
Experts recommend using the “ABCDE rule” to help determine when you should see a physician regarding a suspicious mole or changing skin lesion. Look for the following signs:
- A for asymmetry: One half does not match the other
- B for border irregularity: Irregular or ragged edges
- C for color: The color is not the same throughout
- D for diameter: A mole greater than six millimeters (the size of a pencil eraser)
- E for evolving: A mole is changing in size, shape or color
The next step may be a skin biopsy. A pathologist will examine the specimen under a microscope to determine whether it is a benign mole, atypical or a melanoma.
Melanoma is treated using surgery, radiation and new techniques such as immunotherapy and targeted therapy.
Immunotherapy shows promise
Immunotherapy is one of the most exciting advances in fighting cancer. Using so-called checkpoint inhibitors, one can “release the brakes” of the body’s immune system and attack cancer.
The most important of these cellular systems include that of PD-1 and PD-L1. PD-1 is a molecule on T cells of the immune system. PD-L1, located on cancer cells, interacts with PD-1 in a type of “handshake” allowing cancer cells to evade the immune system. By blocking this interaction, cancer cells become “visible” to the body’s immune system and vulnerable to attack.
CTLA-4 is expressed on T cells and is inhibitory to T cells. Blocking this molecule can also release this “blockade” and “unleash” the power of the immune system on cancer cells.
In a recent study the combination of both a PD-1 and CTLA-4 inhibitor showed significant benefit in those with metastatic melanoma. Tumors shrank in 61% of patients.
Some melanomas have mutations to the BRAF gene causing overproduction of a protein resulting in further tumor growth. Blocking this pathway can halt growth. Inhibitors to the BRAF gene have proven successful. Other mutations that can be exploited include those in the MEK and C-KIT genes.
This exploitation of a patient’s individual tumor characteristics is termed personalized or precision medicine. Pathologists perform this testing on a sample of the tumor taken during biopsy.
What you can do
Prevention programs can prevent more than 21,000 cases of melanoma, saving $250 million in health care costs annually. Important steps you can take include the following:
- Wear a broad brimmed hat, sunglasses and clothing that covers all exposed skin.
- Seek shade in midday hours.
- Use a broad spectrum sunscreen with an SPF of 30 or higher.
- Avoid sunbathing and indoor tanning.
Following these simple steps can help keep you safe and healthy.
ABOUT DR. MICHAEL MISIALEK
Dr. Michael Misialek currently serves as Associate Chair of Pathology at Newton-Wellesley Hospital, Newton, MA. He is the Medical Director of the Vernon Cancer Center, Chemistry Laboratory and Point of Care Testing. He practices in all areas of pathology in a busy community hospital. Holding an academic appointment at Tufts University School of Medicine as a clinical assistant professor of pathology, he regularly instructs medical students and pathology residents. Dr. Misialek is a strong advocate for pathology and is very active in the College of American Pathologists (CAP), serving on the Personalized Healthcare Committee, the political action committee PathPAC, the CAP Foundation and as chair of the Massachusetts delegation in the CAP House of Delegates. He is an inspector with the CAP and has conducted several domestic and international hospital laboratory inspections.
He received his MD from the University of Massachusetts, did an internship in internal medicine at Boston Medical Center and completed his residency in anatomic and clinical pathology at the University of Massachusetts Medical Center. He did a fellowship in general surgical pathology at the University of Florida and is board certified in Anatomic and Clinical Pathology.