What you don't know about melanoma skin cancer can kill you

With the summer barbecue and beach season almost here, it's a good time to protect your body's largest organ — the skin.

Skin cancer is the most common form of cancer in the United States, with hundreds of thousands of cases diagnosed annually.

Most skin cancers can be treated quite easily and are not life threatening. But others can be deadly. The good news is that early detection and recent advances in cutting-edge treatment options like immunotherapy mean that being diagnosed with even the most dangerous kinds of skin cancer may not be a death sentence.

Skin cancer is an umbrella term for all cancers that originate in the skin. The three main types are basal cell carcinoma, squamous cell carcinoma, and melanoma.

Basal cell and squamous cell carcinoma are very common and rarely life threatening. Melanoma is the most aggressive type of skin cancer, and the one I'll focus on here.

Melanoma starts in pigmented skin cells called melanocytes. When the DNA of melanocytes become damaged, new cells can grow out of control, forming an invasive cancer that may spread throughout the body and be fatal. About 80,000 new cases of melanoma are diagnosed every year.

The treatment options for melanoma depend on its stage when detected. Diagnosis and staging are determined by the results of a biopsy, or tissue sample.

Stage 0 melanoma is called "in situ," which means it hasn't invaded surrounding tissue. Stages 1 to 2 are melanomas that have invaded the skin, but only the area around the original location.

Stage 3 melanoma has spread to the lymph nodes, and in Stage 4, melanoma has spread through the lymph system and blood to other parts of the body.

Before melanoma cancers have spread beyond the skin (Stages 1 to 2), most tumors can be treated surgically by removing them.

Stage 3 melanoma, or deep stage 2, may require post-surgical treatments like radiation or immunotherapy.

In the past, chemotherapy was the main treatment for Stage 4 melanoma. Increasingly, though, advances in immunotherapy hold particular benefits. For a melanoma to form, grow, and spread, it must find a way to avoid being detected and killed by the immune system.

Immunotherapy allows us to modulate specific components of the immune system to control many melanomas. In the future, we may be able to use biomarkers to predict how individual patients will respond to specific and combination immunotherapies. We are investigating whether different types of immunotherapy may delay recurrence or increase overall survival in patients with stage III melanoma.

Melanoma can be cured if caught early enough. Watch closely for the warning signs. These include any kind of change in a skin lesion or mole. Moles that change in shape, color, shape, or grow larger than a pencil eraser, should be checked by a doctor-ideally by a dermatologist.

Other signs are skin lesions that bleed, become itchy, or grow darker. And although melanomas usually start in pigmented regions like moles, they can occur in other parts of the skin as well. The safest thing to do is have any changes on your skin checked.

Doctors have identified multiple risk factors associated with all types of skin cancer. Sunlight ultraviolet (UV) rays are an important contributor. Genetic components and immune system defects also play a role.

Anyone can develop skin cancer, but some groups are at especially high risk. You may fall into this category if you have had significant sun exposure, use a tanning bed, have inherited genetic factors, or if your skin has many atypical moles (atypical dysplastic nevi).

Overall, fair-skinned people have a higher risk of developing skin cancer, but even people with very dark complexions can develop skin cancer. No one is immune.

In most cases, skin cancer is the result of damage that accrues over time. The median age of diagnosis is 59 years. The crucial factor is catching skin cancers before they spread. Thankfully, about 80% of melanomas are diagnosed while the disease is still localized. Long-term survival correlates directly with early detection.

Skin cancer is one disease where an ounce of prevention is worth a pound of cure. Take common-sense precautions: minimize sun exposure, never use suntan booths, and apply sunscreen of 30 SPF or higher, year-round.

The UV rays that cause skin cancer are present in the winter months, too. If you have many atypical moles or a family history of skin cancer, you should be monitored by a dermatologist. Between visits, check your skin once a month for any suspicious changes.

For more information on how to prevent, detect, and treat all skin cancers, check out the information hosted by the American Cancer Society ( cancer.org/healthy/besafeinthesun ).

To minimize your risk, be sure to make all the lifestyle modifications possible, and show any suspicious lesions to a doctor.

Even if you have no risk factors for skin cancer, I recommend asking your primary care physician to perform a skin exam whenever you get a checkup. It's not invasive and only takes a few minutes.

Philip Friedlander, MD, PhD is Assistant Professor of Medicine, Hematology and Medical Oncology, and Assistant Professor of Dermatology at the Mount Sinai Hospital and Mount Sinai Beth Israel.