Naylor KL, et al. Am Jrnl Kid Diseases. 2019;doi:doi.org/10.1053/j.ajkd.2018.12.011.
Patients with some cancers have better survival rates than patients on dialysis
Incident patients with ESRD treated with dialysis and tracked during an 18-year period had a higher rate of death than patients with several different solid-organ cancers, according to a study published in the American Journal of Kidney Diseases.
The researchers, led by Kyla L. Naylor, PhD, of ICES in Ontario, Canada, wrote that they undertook the study based on the belief that “an understanding of prognosis for maintenance dialysis patients may be improved if placed in the context of a more common condition such as cancer” and it would “help put the mortality burden of dialysis patients into context and could have implications for future funding and policy decisions.”
The researchers identified 33,500 incident patients on maintenance dialysis from six Canadian databases – the Canadian Organ Replacement Register, the Ontario Cancer Registry, the Registered Persons Database, the Canadian Institute for Health Information Discharge Abstract Database, the National Ambulatory Care Reporting System and the Ontario Health Insurance Plan. Mortality in those patients in a 5-year period was compared to the mortality rate of 532,452 incident patients with cancer. The cancer study group included women with diagnosed breast, colorectal, lung or pancreas cancer and men with prostate, colorectal, lung or pancreas cancer from 1997 to 2015.
“We selected cancers that were common and associated with increased risk for mortality,” the authors wrote.
The results showed that, in men on dialysis, unadjusted survival was 50.8% compared with men having prostate cancer (83.3%) and colorectal cancer (56.1%) at 5 years. However, men on dialysis had better survival than men with lung (14%) and pancreas (9.1%) cancer.
Women on dialysis in the 5-year period had worse unadjusted 5-year survival (49.8%) compared with breast (82.1%) and colorectal (56.8%) cancer, but better survival than lung (19.7%) and pancreas (9.4%) cancer.
However, after adjusting for clinical characteristics, including age, coronary artery disease with angina, myocardial infarction, heart failure, hypertension, diabetes, chronic liver disease and other medical conditions, more men and women with lung and pancreas cancer had a lower risk of death than dialysis patients 4 years or more after diagnosis. Also, women and men 70 years or older on dialysis had unadjusted 10-year survival comparable to men and women in that same age range with pancreas and lung cancer.
“When we examined survival probabilities in maintenance dialysis patients and patients with cancer stratifying by age at diagnosis, we generally found similar trends to the overall analysis,” the authors wrote. “However, we found that women aged 18 to 39 years on maintenance dialysis therapy generally had superior survival outcomes compared with similarly aged women for all cancer types.”
The authors speculate in the paper as to why dialysis patients have lower survival rates compared to patients with the cancers reviewed in the study.
“First, while lifesaving therapies have been developed for patients with cancer, similar advancements have not been made in dialysis patients,” the authors wrote. “Potential explanations for this latter observation include frequent exclusion of dialysis patients from randomized controlled trials, trials that are often underpowered, and a potential misconception that survival cannot be improved. Further, advancements in life-saving therapies may be limited as a result of kidney disease research being arguably underfunded when compared with ‘high-prole’ diseases such as cancer,” they wrote. In 2017, for example, the NIH provided approximately 10-times more money to cancer research compared to kidney disease research.
Likewise, although kidney transplantation is the best treatment option for patients on dialysis in terms of having better chances of survival, there are barriers to receiving a transplant, including organ availability.
“The lack of improvement in unadjusted survival observed in this study is concerning because the dialysis population is expected to increase by more than 3 million worldwide in the next 15 years,” the researchers wrote. The results of the study “do highlight the urgent need to fund, develop, and test interventions to improve survival in maintenance dialysis patients and include such patients in trials for other conditions (eg, coronary heart disease),” the researchers wrote. “Furthermore, results highlight the need for advance care planning and can be used to facilitate this planning in elderly patients beginning treatment with maintenance dialysis." –by Mark E. Neumann