Solid-organ transplant recipients with pretransplant malignancies (PTM) have worse overall survival (OS) compared to recipients without history of malignancy. However, it is unknown whether the increased risk of mortality is due to recurrent cancer-related deaths.
All solid-organ transplant recipients in Ontario between 1991 and 2010 were identified and matched 1:2 to recipients without PTM using a propensity score. OS was compared using the Kaplan-Meier estimator and Cox proportional hazard models. For cancer-specific mortality and cancer recurrence, cause-specific hazard models were used and the cumulative incidence was plotted.
Recipients with PTM had a worse OS compared with recipients without PTM (median OS, 10.3 years vs 13.4 years). Recipients with PTM were not only at increased risk of cancer-specific mortality (cause-specific hazard ratio, 1.85; 95% confidence interval [CI], 1.20-2.86) but also at increased risk of noncancer death (cause-specific hazard ratio, 1.29; 95% CI, 1.08-1.54). Compared with recipients without PTM, recipients with high-risk PTM had higher all-cause mortality (hazard ratio, 1.81; 95% CI, 1.47-2.23). Recipients with low-risk PTM were not at increased risk (hazard ratio, 1.06; 95% CI, 0.86-1.31).
Recipients with PTM are at increased risk of all-cause mortality compared to recipients without PTM. This increased risk was noted for both cancer-specific and noncancer mortality. However, only those with high-risk PTM had worse outcomes.
Using a propensity score matched cohort study design, the authors report on a worse survival of organ transplant recipients with pretransplant malignancy than without. However, the increased risk, both cancer specific or not, is mainly conveyed by high risk malignancies.
1 Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON.
2 Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON.
3 Department of Surgery, St. Michael's Hospital, Toronto, ON.
4 Division of General Surgery, Department of Surgery, University of Toronto, Toronto, ON.
5 Institute of Clinical Evaluative Sciences, Toronto, ON.
6 Division of Nephrology and the Kidney Transplant Program, Toronto General Hospital, University Health Network and Department of Medicine, University of Toronto, Toronto, ON.
Received 15 October 2017. Revision received 6 February 2018.
Accepted 7 February 2018.
The authors declare no conflicts of interest.
This study was funded by a Canadian Institutes of Health Research (CIHR) Operating Grant (funding reference no. 115164) and CIHR Foundation Grant (funding reference no. 148470). The funding sources had no role in the design or conduct of the study; collection, management, analysis, or interpretation of the data; or preparation, review or approval of the article.
This work was presented as an oral presentation (Abstract number: 822) at the 2016 American Transplant Congress, Boston, MA, June 11-25, 2016.
S.A.A. participated in the hypothesis generation and study design, data acquisition, statistical analysis, interpretation of findings, writing of the article, and approval of the final draft. R.S. participated in the study design, interpretation of findings, and approval of the final draft. S.J.K. participated in the study design, interpretation of findings, and approval of the final draft. N.N.B. participated in the hypothesis generation research design, interpretation of findings, writing of the article, and approval of the final draft.
Correspondence: Nancy Baxter, MD, PhD, Division of General Surgery, St. Michael's Hospital, 040-16 Cardinal Carter Wing, 30, Bond St, Toronto, ON, Canada M5B 1W8. (BaxterN@smh.ca).