Melanoma is one of the most aggressive forms of skin cancer, developing from melanocytes—the cells that produce the pigment melanin. Its insidious nature lies in its ability to metastasize rapidly, making early diagnosis and timely treatment critical for prognosis. In recent years, scientific research has revealed unexpected links between melanoma and other diseases, such as Parkinson's disease and Meniere's disease, and has made significant progress in developing effective therapeutic methods, including immunotherapy.
Non-obvious risk factors: the link to Parkinson's disease and Meniere's disease
Traditionally, the main risk factors for developing melanoma include excessive exposure to ultraviolet radiation, the presence of a large number of moles, fair skin type, and heredity. However, new studies point to the existence of more complex interrelationships with other systemic diseases.
- Parkinson's disease (PD): Patients with Parkinson's disease have an increased risk of developing melanoma [1]. A study conducted at Duke University showed that in people with PD, invasive melanomas were localized in the head and neck area in 39.5% of cases, compared to 25.3% in the control group. For non-invasive melanomas, this figure was 48.7% versus 39.1%, respectively. Moreover, half of the metastatic melanomas in patients with PD also occurred in the head and neck area [1]. Logistic regression revealed that the probability of developing melanoma in the head/neck area in patients with PD is 2.09 times higher than in the control group [1].
- Genetic link: This association is not accidental. Studies have identified a significant positive genetic correlation between melanoma and Parkinson's disease (correlation coefficient 0.17) [3]. This means that there are shared genetic factors and biological pathways that may contribute to the development of both diseases. Seven genes have been identified, including PIEZO1, TRAPPC2L, and SOX6, which may act as mediators of this genetic link [3].
- Meniere's disease: Another unexpected discovery is related to Meniere's disease—a chronic inner ear disorder characterized by episodes of vertigo, tinnitus, and hearing loss. Real-world data analysis showed that the prevalence of melanoma among patients with Meniere's disease was 12-15 times higher (6%) than in the general US population [5]. This underscores the need for increased oncological vigilance in this group of patients.
These data indicate the importance of a comprehensive approach to monitoring patients with Parkinson's disease and Meniere's disease, including regular dermatological examinations for early detection of melanoma [1].
Diagnosing melanoma: what to look for?
Early detection of melanoma is the key to successful treatment. It is important to regularly examine your skin and pay attention to any changes in moles or the appearance of new lesions. A classic method of self-diagnosis is the "ABCDE" rule:
- A (Asymmetry) — Asymmetry: one half of the mole does not match the other.
- B (Border) — Border: irregular, ragged, or blurred edges.
- C (Color) — Color: uneven color, including shades of brown, black, red, white, or blue.
- D (Diameter) — Diameter: most melanomas have a diameter of more than 6 mm, although they can be smaller.
- E (Evolving) — Evolving: any change in size, shape, color, the appearance of itching, bleeding, or other symptoms.
For patients in risk groups, especially those with Parkinson's disease, regular check-ups with a dermatologist are of particular importance, as melanomas can have atypical localization, for example, on the head and neck [1].
Modern approaches to melanoma treatment
Treatment for melanoma depends on the stage of the disease. In the early stages, the primary method is surgical removal of the tumor. However, for metastatic melanoma, when cancer cells have spread beyond the primary site, more complex and systemic approaches are required. Over the last decade, a significant breakthrough in the treatment of metastatic melanoma has been achieved thanks to the development of immunotherapy.
Immunotherapy: efficacy and potential risks
Immunotherapy, particularly the use of immune checkpoint inhibitors (ICIs), has revolutionized the treatment of many types of cancer, including metastatic melanoma, significantly increasing patient survival [2]. These drugs activate the body's own immune system to fight cancer cells. Combination immunotherapy, such as ipilimumab and nivolumab, has shown high efficacy in fighting advanced forms of melanoma.
However, by activating the immune system, ICIs can cause immune-related adverse events (irAEs), which can affect various organs and systems, sometimes posing a threat to life [2]. One such rare but potentially fatal complication is immune-related hepatitis—inflammation of the liver caused by excessive activity of the immune system [2].
To monitor treatment efficacy and detect irAEs, positron emission tomography combined with computed tomography (PET/CT) with 18F-FDG is often used. This examination allows for the visualization of the metabolic activity of tissues. In the case of immune-related hepatitis, increased 18F-FDG uptake in the liver may be observed on PET/CT, indicating an inflammatory process [2]. It is important that clinicians interpreting PET/CT results pay attention to the state of the liver and, if hepatitis is suspected, promptly inform the attending physicians to optimize therapy and patient care [2]. Early detection and timely treatment of irAEs are critical for preventing serious complications and improving treatment outcomes.
Sources
- [1] Clinicopathologic Characteristics of Melanoma in Patients with Parkinson Disease. https://pubmed.ncbi.nlm.nih.gov/36876218/
- [2] ¹⁸F-FDG PET/CT-visualised immune-related hepatitis after immune checkpoint inhibitor combination treatment in a patient with metastatic melanoma. https://pubmed.ncbi.nlm.nih.gov/42716692/
- [3] Overlapping genetic architecture between Parkinson disease and melanoma. https://pubmed.ncbi.nlm.nih.gov/31845298/
- [5] Real-world analysis of Ménière's disease: treatment patterns, surgical trends, demographic disparities and co-morbidities using TriNetX data. https://pubmed.ncbi.nlm.nih.gov/42252840/
Disclaimer: The information provided in this article is for reference purposes only and cannot replace professional medical advice. Always consult a qualified specialist for the diagnosis and treatment of any diseases.