Melanoma is the deadliest form of skin cancer. It develops when unrepaired DNA damage to skin cells triggers mutations that cause the cells to multiply rapidly and form malignant tumors. These cancerous cells originate in pigment-producing melanocytes in the basal layer of the epidermis. Melanomas are usually brown or black, but can also be skin-colored, pink, red, purple, blue or white. Melanoma is caused mainly by intense, occasional UV exposure (frequently leading to sunburn), especially in those who are genetically predisposed to the disease. The risk is also higher for people with light skin color, with blue or green eyes, and with blond or red hair.
What are the different types of melanoma?
There are four main types of melanoma:
- Superficial spreading melanoma: This is the most common type, accounting for 70% of melanomas. It grows outwards at first, spreading across the surface of the skin before penetrating more deeply over time.
- Nodular melanoma: This is the most aggressive type, accounting for about 15% of melanomas. It usually starts growing downwards into the skin right from the start, without any outward spread across the surface first.
- Lentigo maligna melanoma: This accounts for 10-15% of melanomas. It begins as a Hutchinson’s freckle, spreading outwards over many years before invading downwards into deeper skin layers.
- Acral lentiginous melanoma: This type occurs on the palms of the hands, soles of the feet or under nails. It accounts for 2-3% of melanomas and is more common on darker-skinned people.
What makes a melanoma more deadly?
The deadliest melanomas are ones that:
- Are thicker – The risk of spread and death increases as the tumor grows deeper into the skin. Melanomas over 4 mm thick have a very high risk of metastasis.
- Have ulcerated surfaces – Melanomas that lose the outer layer of skin and become an open wound are more likely to spread.
- Have mitotic rate of 1/mm2 or higher – The mitotic rate measures how rapidly cancer cells are dividing and replicating. Higher rates indicate faster growing, more aggressive tumors.
- Spread to the lymph nodes – melanoma cells can travel via lymph vessels to nearby lymph nodes. Spread to lymph nodes is associated with decreased survival.
- Spread to distant organs – Advanced metastatic melanomas that spread from the skin to distant sites like the brain, lungs or liver are very difficult to treat and often fatal.
What are the survival rates for metastatic melanoma?
Once melanoma has spread to other parts of the body, it is much harder to treat and survival rates are lower. Some key statistics on survival rates include:
- Stage IV melanomas that have spread to distant lymph nodes, organs or widely through the skin have a 5-year survival rate of about 15-20%.
- Melanomas that have spread to distant organs like the lungs or brain have a 5-year survival of only 10%.
- Melanomas with brain metastases have an average survival time of only 2 to 4 months if left untreated.
Survival rates have been improving with newer treatments like immunotherapy and targeted therapies. But metastatic melanoma remains challenging to treat effectively.
What features make a melanoma high risk?
Doctors assess a melanoma’s risk level based on features like:
- Breslow thickness – measured in mm from the top layer down into the skin. Over 4 mm is high risk.
- Ulceration – loss of the outer skin layer. Present in about 10-15% of melanomas.
- Mitotic rate – the rate of cancer cell division under the microscope. Higher rates indicate faster growing tumors.
- Anatomic site – head and neck melanomas have higher risk due to lymph drainage patterns.
- Presence of metastases – spread to lymph nodes or distant sites marks advanced disease.
High risk melanomas have a greater tendency to recur after initial treatment and have higher mortality rates. Identifying them early is critical.
What are some warning signs of melanoma?
Look for these ABCDE warning signs when monitoring moles and other skin spots:
- Asymmetry – the two halves don’t match if you draw a line through the middle.
- Borders – irregular, ragged, notched or blurred edges.
- Color – more than one color present, like tan, brown, black, red, white or blue.
- Diameter – larger than 6 mm across, about the size of a pencil eraser.
- Evolving – changes in size, shape, color, elevation, or another trait.
Also watch for any new black spot on the skin, or one that changes over weeks to months. See a dermatologist promptly if you notice any of these signs.
What screening exams help detect melanoma early?
These methods can improve early melanoma detection:
- Skin self-exams – examine your whole body regularly for new or changing moles or spots.
- Clinical skin exam – done by a dermatologist, usually annually for those at higher risk.
- Photography – comparing pictures of moles over time to spot changes.
- Dermoscopy – a handheld magnifier and light used by doctors to examine pigmentation patterns.
- Biopsy – removing all or part of a suspicious growth to examine cells under a microscope.
Catching melanoma early before it invades deeply leads to better outcomes. Know what’s normal for your skin and follow up on anything new or changing.
How is melanoma staged?
The AJCC melanoma staging system assesses:
- Tumor thickness (T) – rated T1 through T4 based on mm depth of skin invasion
- Ulceration (U) – present or absent
- Lymph node spread (N) – rated N0 to N3 based on number and extent of lymph nodes involved
- Metastases (M) – M0 for no distant spread, M1 for metastases present
Combining these elements gives an overall stage of 0 through IV. Higher stages indicate more advanced disease.
| Stage | Definition |
|---|---|
| 0 | Tis, N0, M0: Melanoma in situ, no spread |
| IA | T1a, N0, M0: Under 1.0 mm thick, no ulceration or spread |
| IB | T1b or T2a, N0, M0: Up to 2.0 mm thick, no ulceration or spread |
| IIA | T2b or T3a, N0, M0: 2.01-4 mm thick, no ulceration or spread |
| IIB | T3b or T4a, N0, M0: Over 4 mm thick, no ulceration or spread |
| IIC | T4b, N0, M0: Any thickness with ulceration, no spread |
| III | Any T, N1-3, M0: Lymph node spread, no distant metastases |
| IV | Any T, any N, M1: Distant metastases present |
What are some treatment options for melanoma?
Common treatments used for melanoma include:
- Surgery – to remove the primary tumor and lymph nodes if spread is present. Wider excision margins are needed for thicker tumors.
- Immunotherapy drugs – work by enhancing the immune response against melanoma cells. Types include ipilimumab (Yervoy) and PD-1 inhibitors like pembrolizumab (Keytruda).
- Targeted therapies – drugs that block specific mutations that allow melanoma cells to grow unchecked, like BRAF inhibitors.
- Chemotherapy – cytotoxic drugs that kill rapidly dividing cancer cells. Often used when melanoma resists other treatments or is advanced.
- Radiation – may help treat localized recurrences or manage pain and other symptoms when melanoma has spread.
Treatment plans are tailored for each patient based on the stage, molecular traits of the cancer and other factors.
What are some prognostic factors for melanoma?
Factors that provide information about a melanoma’s likely course and outcome include:
- Breslow thickness – the strongest prognostic factor, thicker tumors have worse prognosis.
- Ulceration – linked with more aggressive behavior and higher mortality.
- Mitotic rate – more rapid cell division indicates worse outcomes.
- Site – head and neck melanomas have higher recurrence and mortality rates.
- Metastases – spread to lymph nodes or distant sites worsens prognosis.
- Lactate dehydrogenase (LDH) – elevated blood LDH can mark advanced metastatic disease.
- Mutations – certain mutations like BRAF V600E mutation can influence targeted therapy response.
Prognostic factors guide treatment choices and provide insight into a patient’s expected outcome.
What research is being done on melanoma?
Key areas of melanoma research include:
- Developing more effective immunotherapy drugs and combination therapies.
- Understanding resistance mechanisms to targeted drugs like BRAF inhibitors.
- Improving early detection through blood tests and other screening approaches.
- Identifying genetic and molecular markers that drive melanoma growth and progression.
- Expanding the use of neoadjuvant therapies to shrink tumors before surgery.
- Optimizing radiation techniques to help control oligometastases.
- Finding better treatments for brain metastases.
Research is also exploring the role of the tumor microenvironment, melanoma stem cells, and using nanoparticles to deliver therapy. The goals are to improve cure rates, survival, and quality of life for melanoma patients.
What are some prevention tips for melanoma?
- Use sunscreen with SPF 30 or higher and broad-spectrum protection.
- Avoid direct sun exposure between 10am and 4pm when rays are strongest.
- Wear protective clothing like hats, long sleeves and sunglasses outside.
- Don’t use tanning beds, which emit harmful UV radiation.
- Examine skin regularly for new or changing moles and spots.
- See a dermatologist for an annual skin cancer screening.
- Use extra caution if you are pale-skinned, blonde or red-haired.
- Take precautions even on cloudy days when UV rays still penetrate.
Reducing UV radiation exposure and catching melanomas early are key to lowering risk and improving prognosis.
Conclusion
The deadliest melanomas are those that are thicker, ulcerated, fast growing, arising on the head or neck, or have spread to lymph nodes or distant sites. Public education efforts that promote early detection, screening, and sun safety practices are critical to reduce mortality from melanoma. Ongoing research seeks to develop better treatments and ultimately find a cure even for advanced disease.
