Off-label drug use, where a marketed drug is used outside its approved indication, may allow early access to new and promising treatments. However, its use can be a source of controversy, due to limited evidence for clinical benefit and lack of cost/QALY-estimates, leading to challenging prioritization issues. The number of drugs suitable for off-label use is expected to further increase in the coming years, owing to the rapid progress in the field of oncology, in particular with the current era of precision medicine and targeted therapies. This also challenges the traditional method of running clinical trials, with eligible patient populations commonly being small, underpinning the importance of gaining supplementary real-world evidence from well performed observational studies.

This prospective observational study will therefore assess real-world outcomes of patients treated with off-label anti-cancer drugs, including efficacy in terms of response rates, time to progression/relapse measures and survival; patient-reported outcome measures (PROMS) and self-reported side-effects/toxicity; as well as collecting blood samples for a biobank for further translational research. Further, the study will give a descriptive analysis of the current practice of off-label use of anti-cancer drugs in Norway, including prevalence estimation and health care related cost analyses.

Inclusion Criteria:

• Verified cancer diagnosis (based on radiological, histological/cytological or operative evidence).
• Treatment with off-label anti-cancer drug.
• Age ≥ 18 years
• Able to provide written informed consent.

Exclusion Criteria:

• None

Any patient accepted by the leadership in the Department of Oncology at OUH to receive anti-cancer treatment off-label from the date of start of the study is eligible for inclusion. Of note, this does not include off-label use of drugs used for supportive care.