PhD ceremony Mr. M.G. Niebling: Improving staging accuracy in melanoma

PhD ceremony: Mr. M.G. Niebling

Dissertation: Improving staging accuracy in melanoma

Promotor(s): prof. H.J. Hoekstra, prof. J. Thompson

Faculty: Medical Sciences

The incidence of melanoma is rising worldwide. Due to the unpredictability and erratic dissemination of melanomas, its management is challenging. It is currently almost impossible to cure distant disseminated melanoma patients, although new therapies, including immunotherapy and drug targeted therapies, offer hope for the future. Accurate staging is extremely important for clinical decision making and often starts with the histopathology of the primary melanoma. This thesis shows that the histopathologic diagnosis of melanoma is subjective and complex. Furthermore we showed that revision by a specialist melanoma pathologist is required before definitive diagnosis and treatment. The essential pathologic features are Breslow thickness, ulceration, and tumor mitotic rate. We found a high interobserver agreement between pathologists for these pathologic features. Another melanoma pathologic feature is microsatellites. Our studies showed that prognosis of melanoma patients is poor when microsatellites are present.

For the detection of melanoma metastases nuclear imaging plays an important role. FDG-PET/CT is essential in melanoma patients with clinically detectable lymph node metastases, as it improves the staging of these patients. Due to improvement of staging accuracy, and as a result improved understanding of its biological behavior, melanomas are becoming more predictable. Accurate staging of patients will inform them about their prognosis more accurately, allowing medical multidisciplinary teams to treat melanoma patients with more suitable, patient-tailored, therapies.