Zheng G, Chattopadhyay S, Sundquist K, et al. - In this study, researchers measured survival in individuals with different types of second primary cancers (SPCs), compared with known poor prognostic indicators of metastatic disease. For melanoma and any SPCs, they obtained data from the Swedish Cancer Registry between 2003 and 2015, including clinical TNM classification. They classified SPCs into three ‘prognostic groups’ based on the 5-year relative survival of these cancers as the first primary cancer. They created Kaplan-Meier survival curves and calculated hazard ratios by using Cox regression, adjusted for a number of variables and treating the diagnosis of SPC as a time-dependent variable. The data suggested that SPCs are a more common negative prognostic factor for melanoma. Further trials to improve melanoma survival require to target SPCs.