BACKGROUND: Drug licensing and reimbursement authorities worldwide are considering new ways to stimulate market access for innovative medicines such as accelerated approval and conditional coverage. Early release of pharmaceuticals calls for more responsive decision-making alongside continuous evidence generation throughout clinical development. We explore whether changing trends in clinical evidence considerations for health technology assessment (HTA) by the National Institute for Health and Care Excellence (NICE) may help inform future evidence requirements for rapid and early HTA. OBJECTIVES: We investigate how the submission and acceptability of clinical evidence for single, multiple and repeated assessments of cancer drugs by NICE have changed in the past decade. METHODS: We reviewed technology appraisals published online since February 2002 by NICE for pharmaceuticals in oncology. Information regarding the clinical evidence included and the methods used to analyse relative treatment effects across relevant comparators was extracted. Manufacturer submissions, assessment reports, and final appraisal determinations were considered for longitudinal comparison. RESULTS: Out of a total of 254 appraisals identified since 2002, 85 assessed cancer drugs and 76 of these were included for review based on available documentation. Only 11 products had been re-assessed to date with initial guidance superseded by a multiple technology appraisal or clinical guideline. We found a greater reliance on phase II and observational data in recent appraisals, particularly for novel therapies in areas of high unmet need. Limited data was also accompanied by an increase use of surrogate outcomes and extrapolation of observed short-term clinical benefits. Recent submissions were also marked by the uptake of network meta-analysis methodologies. CONCLUSIONS: NICE has previously recommended cancer drugs based on immature clinical data allowing for considerable uncertainty in ‘real-world’ effectiveness estimates. However, these examples remain the exception to the rule; moreover our review highlighted a need for methodological development to deal with early clinical evidence.