The Association between Dialysis Dose and Risk of Cancer Death in Patients Undergoing Hemodialysis: The Q-Cohort Study

OBJECTIVE: Uremic toxins are known risk factors for cancer in patients undergoing hemodialysis (HD). Although adequate removal of uremic toxins might reduce the cancer risk by improving subclinical uremia, the relationship between the dialysis dose and risk of cancer death in patients undergoing HD remains unclear. METHODS: In this prospective observational study, 3,450 patients undergoing HD were followed up for 4 years. The primary outcome was cancer death. Patients were divided into quartiles according to their baseline Kt/V levels. The association between the Kt/V levels and risk of cancer death was estimated using the Kaplan-Meier method and Cox proportional-hazards model. RESULTS: A total of 111 patients (3.2%) died from cancer during the 4-year observational period. The 4-year survival rate decreased linearly with decreasing Kt/V. The multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for cancer death were 2.23 (95% CI, 1.13-4.56), 1.77 (0.88-3.63), and 1.89 (1.04-3.56) in quartile (Q)1, Q2, and Q3, respectively, compared with patients in the highest Kt/V category (Q4) (p for trend = 0.06). Every 0.1 increase in Kt/V was associated with a reduction of 8% in cancer death (HR 0.92, 95% CI, 0.85-0.99). CONCLUSION: A lower dialysis dose might be associated with a higher risk of cancer death in patients undergoing HD. Kt/V is a simple indicator of dialysis dose used in clinical practice and might be a useful modifiable factor for predicting the risk of cancer death. Further basic and interventional studies are needed to confirm the apparent reduction in cancer death associated with increasing the dialysis dose.