Clinical associations for traditional and complementary medicine use among Norwegian cancer survivors in the seventh survey of the Tromsø study: a cross-sectional study

Kiwumulo Nakandi, Trine Stub, Agnete E. Kristoffersen

Cancer survivors are a diverse group with varying needs that are patient-, disease-, and/or treatment-specific. Cancer survivors have reported supplementing conventional anti-cancer treatment with Traditional and Complementary Medicine (T&CM). Although female cancer survivors are reported to have more severe anticancer adverse effects, little is known about the association between anticancer treatment and T&CM use among Norwegian cancer survivors. The aims of this study are therefore to investigate (1) associations between cancer diagnosis characteristics and T&CM utilization and (2) associations between anticancer treatment and T&CM utilization among cancer survivors in the seventh survey of the Tromsø study. Data was collected from the seventh survey of the Tromsø Study conducted in 2015-16 among all inhabitants of Tromsø municipality aged 40 and above (response rate 65%), where inhabitants received online and paper form questionnaires. Data from the data linkage to the Cancer Registry of Norway for cancer diagnosis characteristics was also used. The final study sample was made up of 1307 participants with a cancer diagnosis. Categorical variables were compared using Pearson's Chi-square test or Fisher's exact test while independent sample t-test was used to compare continuous variables. The use of T&CM the preceding 12 months was reported by 31.2% of the participants with natural remedies as the most reported modality of T&CM (18.2%, n = 238), followed by self-help practices of meditation, yoga, qigong, or tai chi, which was reported by 8.7% (n = 114). Users of T&CM were significantly younger (p = .001) and more likely to be female (p < .001) than the non-users, with higher use of T&CM among female survivors with poor self-reported health and being 1-5 years post-diagnosis. Lower use of T&CM was found among female survivors who received a combination of surgery with hormone therapy and those who received a combination of surgery with hormone therapy and radiotherapy. Similar usage was seen in male survivors, but not at a significant level. For both male and female survivors, T&CM was most frequently used by those with only one cancer diagnosis (p = .046). Our results indicate that the profile of the Norwegian cancer survivor who uses T&M is slightly changing compared to previous findings. Additionally, compared to male survivors, more clinical factors are associated with use of T&CM among female cancer survivors. These results should serve as a reminder to conventional health care providers to discuss the use of T&CM with patients across the entire cancer survivorship continuum to promote safe use, especially among female survivors.