Objective: A waiting list randomised control trial has shown the Move More Pack, a print-based intervention supported by Internet tools, to improve physical activity levels in cancer survivors; however, one-third do not improve from the intervention. The objective of this process evaluation is to understand intervention use, the mechanisms of impact, the perceived benefits, and the contextual factors influencing these, identifying for whom it is a useful resource.

Methods: A mixed methods process evaluation, based on guidance from the UK Medical Research Council, including 181 questionnaire responses on intervention use and physical activity improvement over 12-weeks, 56 open text responses and 17 semi-structured interviews.

Results: The Move More Pack was suggested to be most useful when delivered towards the start of the cancer journey to those with a positive attitude to fighting cancer but with a low level of physical activity, capitalising on a teachable moment. It was suggested that healthcare professionals could support the effective distribution of the Move More Pack. The intervention’s printed components were more popular and well used than the Internet tools. The printed intervention components were positively correlated with physical activity improvement but the Internet tools were not. Females were more likely to use the intervention’s printed components than males. Cancer survivors using the intervention reflected that they had increased confidence and motivation for physical activity and other lifestyle behaviours.

Conclusion: The Move More Pack should be offered by healthcare professionals, during cancer treatment, when health is salient, to those with a positive attitude to fighting cancer but with low levels of physical activity. Use of the intervention’s printed components are more likely to improve physical activity than the Internet tools and are more likely to be used by females. The use of Internet tools to support physical activity improvement in cancer survivors requires further investigation.