Conditional survival of malignant melanoma in The Netherlands: 1994-2008

Cutaneous malignant melanoma causes the majority of skin cancer related deaths and features increasing incidence and mortality rates in the Netherlands. Conditional survival analysis is performed on patients who survived the preceding year(s).

Patients with invasive melanoma, as recorded in the population-based Netherlands Cancer Registry, were included. To assess prognosis of melanoma survivors according to gender and Breslow thickness, conditional five-year relative survival was calculated for lymph node negative melanoma patients and conditional one-year relative survival was analysed for melanoma patients with and without nodal involvement.

Between 1994 and 2008, 40,050 patients developed a melanoma (stage I-III, of whom 6% with nodal involvement). Six to 8years after diagnosis, survival of patients with a 1-2mm (T2) thick melanoma equalised the general population. Conditional five-year relative survival for patients with >4mm thick (T4) melanomas increased from about 60% at diagnosis to 90% at 7years after diagnosis. Largest improvements were found in patients with thick melanomas and female patients with nodal involvement.

The prognosis for melanoma survivors improved with each additional year of survival after diagnosis, except for patients with a ⩽1mm thick melanoma, who never had any excess mortality during follow-up. Conditional survival of melanoma was better amongst females, amongst those with lower Breslow thickness and nodal stage.