Data will be collected by mailed or online questionnaires at 6, 9, and 12 months as well as 2, 3, 4 and 5 years post-diagnosis from 2000 cancer patients. Besides questionnaires on socio-demographic, clinical and patient reported outcomes, saliva samples will be collected in order to gain new insights into biological mechanisms. Moreover, detailed data on screening, diagnosis and counseling as well as therapies offered and administered to reduce fatigue will be surveyed, as well as the patients' state of knowledge, perception and prevailing needs regarding fatigue. Tumor and cancer therapy data will be extracted from the Epidemiological Cancer Registry.