Assessing the impact of cancer among Dutch non-Hodgkin lymphoma survivors compared with their American counterparts: a cross-national study.

PURPOSE: To understand cultural differences in the impact of cancer (IOC) by (i) performing an independent psychometric evaluation of the Dutch version of the Impact of Cancer Scale version 2 (IOCv2) in a non-Hodgkin lymphoma (NHL) sample and (ii) examining differences between Dutch and American NHL survivors in perceived IOC and identifying associations with socio-demographic and clinical characteristics.

METHODS: Data collected from 491 Dutch and 738 American NHL survivors were used in this study. IOCv2 responses were obtained from all survivors; the Dutch survivors also completed the European Organization for Research and Treatment of Cancer Quality of Life Core questionnaire, which measures quality of life.

RESULTS: Exploratory factor analysis of the Dutch version yielded a factor solution similar to the American structure but with some subscales merging into single factors. Internal consistency was good; Cronbach's alpha was 0.88 for the Positive and 0.94 for the Negative summary scales. Large differences were observed between survivors, whereby Dutch survivors reported fewer Positive (Δ -0.4, p < 0.001, effect size: 0.27) and more Negative (Δ 0.2, p ≤ 0.001, effect size: 0.13) impacts of cancer independent of socio-demographic and clinical characteristics.

CONCLUSION: Similar impact domains of the IOCv2 were observed in the Dutch sample, providing evidence that IOCv2 scales measure common and important survivor concerns across two different Western nations. Higher positive impacts for US survivors might be explained by more personal control and availability of supportive services. Future research should focus on determinants of the IOC in both Dutch and American survivors to gain better understanding of the factors that might improve it and suggest how health care may be modified toward that end.