Early detection of cancer as well as advances in therapy and supportive care have resulted a prolonged survival period of time after cancer. In the Netherlands the 5-year relative survival for all types of cancers combined increased from 47% in 1989-1993 to 59% in 2004-2008. Once patients have survived long enough (i.e. 10 years) since diagnosis of their cancer, their life expectancy usually becomes almost the same as people without a cancer (conditional 5-year relative survival>95%). A Netherlands Cancer scenario Report expected the prevalence of second cancer patients to increase from 14,000 in 1985 to 24,000 (excl. skin cancer) in 2000 when assuming an average increase of duration of survival by 1% per annum. The Signallling report in 2004 from the Dutch Cancer Society estimated the prevalence of multiple malignancies (MMs) to reach around 100,000 cases in 2015 in the Netherlands due to a twofold number of cancer survivors since 2005. Since a second cancer diagnosis may impair survival and is likely to affect quality of life amongst cancer survivors we should be interested in prevention and early detection and its undoubtedly more complex treatment. MMs are defined as two or more primary cancers occurring in an individual that are neither an extension, nor a recurrence, nor a metastasis of the first tumor1.