Quality of Life in Long-term Cancer Survivors: Implications for Future Health Technology Assessments in Oncology

Cancer survival rates have improved dramatically in recent decades due in part to pharmaceutical advances, with a growing range of increasingly effective and targeted medicines being developed, such as immunotherapies. In the economic modelling of such treatments, the question arises of which utilities should be assigned to patients who show a long-term, durable response.
In recent critiques of economic models in this area by the National Institute for Health and Care Excellence (NICE), the idea that long-term cancer survivors (LTCS) who have received such treatments could report quality of life (QoL) scores which are similar to, or higher than, those of equivalent general population samples has not been viewed as credible. 
This literature review examines whether there is evidence to support the assumption that the QoL of LTCS can be similar to that of age-/sex-matched population samples. The search strategy initially focused on identifying studies that assessed QoL in LTCS treated with immunotherapy, but the lack of studies necessitated a broader approach (i.e. any treatment type).
In total, 20 papers were included in the review, representing 23 studies. The studies covered a range of different cancers, with the majority collecting data from over 100 LTCS. LTCS included in the studies were more likely to have experienced early-stage cancer relative to late-stage cancer. Of the included studies, just under half (n=11) compared the QoL of a sample of LTCS and the QoL of a control group. Only one of these studies concluded that the evidence suggested that QoL was worse for LTCS relative to the control group.
The majority of studies that made explicit comparisons between LTCS and the general population suggested that levels of QoL in the two groups are quite similar. This could provide some evidence to support an argument for applying general population utilities to LTCS in economic models for cancer treatments.
It might be that cancer treatment is effective in restoring patients to a high level of QoL in the long-term. However, it is also possible that cancer patients ‘adapt’ to their condition over the long-term, though no studies explored this in detail. Alternatively, individuals with cancer may improve their lifestyle following diagnosis, which could improve their QoL in the long-term. However, evidence of lifestyle change is mixed in the included studies.
There are potential limitations to the data. This could include selection bias, where a fully representative sample cannot be recruited. In this case, it could be that healthier LTCS were more likely to have been included in the studies. In addition, the reporting and analyses conducted were of a low quality in some of the studies.
Notwithstanding the very limited evidence base and potential limitations, of the studies reporting comparisons with population norms, the majority provided evidence that the QoL of LTCS is similar to that of the general population. However, it is unclear how generalisable the results are, due to the different study settings. 
Therefore, care is required in asserting that general population utilities could be used to represent LTCS in economic models. Further research is required in a broad range of cancer and treatment types to provide a stronger understanding of QoL in LTCS. In particular, there is a need for more data on the QoL of LTCS who were treated with immunotherapy for advanced/metastatic disease
This study was undertaken by Patricia Cubi-Molla, David Mott, Koonal Shah, Mike Herdman and Nancy Devlin, in collaboration with Yvonne Summers of The Christie and Manchester University NHS Foundation Trusts. The study was funded by Roche Products Ltd. 
Download the full report here.
For more information about OHE’s research on this topic, contact Koonal Shah.
Cubi-Molla, P., Mott, D., Shah, K., Herdman, M., Summers, Y. and Devlin, N. 2018. Quality of Life in Long-term Cancer Survivors: Implications for Future Health Technology Assessments in Oncology. OHE Consulting Report, London: Office of Health Economics. RePEc
Related Research
Lorgelly, P.K. and Neri, M. 2018. Survivorship Burden for Individuals, Households and Society: Estimates and Methodology. Journal of Cancer Policy, 15(B), pp.113-7. DOI
Devlin, N., Lorgelly, P. 2017. QALYs as a Measure of Value in Cancer. Journal of Cancer Policy, 11, pp.19-25. DOI

Posted in EQ-5D and PROMs, NICE | Tagged Consulting Reports