Causes of death among cancer patients

abstract
 

Background: The purpose of our study was to characterize the causes of death among cancer patients as a function of objectives: (I) calendar year, (II) patient age, and (III) time after diagnosis.

Patients and Methods: US death certificate data in SEER Stat 8.2.1 were used to categorize cancer patient death as being due to index-cancer, non-index-cancer, and non-cancer cause from 1973 to 2012. In addition, data were characterized with standardized mortality ratios (SMRs), which provide the relative risk of death compared to all persons.

Results: The greatest relative decrease in index-cancer death (generally from > 60% to < 30%) was among those with cancers of the testis, kidney, bladder, endometrium, breast, cervix, prostate, ovary, anus, colorectum, melanoma, and lymphoma. Index-cancer deaths were stable (typically > 40%) among patients with cancers of the liver, pancreas, esophagus, and lung, and brain. Non-cancer causes of death were highest in patients with cancers of the colorectum, bladder, kidney, endometrium, breast, prostate, testis; > 40% of deaths from heart disease. The highest SMRs were from non-bacterial infections, particularly among < 50 year olds (e.g. SMR > 1,000 for lymphomas, p < 0.001). The highest SMRs were typically within the first year after cancer diagnosis (SMRs 10 - 10,000, p < 0.001). Prostate cancer patients had increasing SMRs from Alzheimer's disease, as did testicular patients from suicide.

Conclusion: The risk of death from index- and non-index-cancers varies widely among primary sites. Risk of non-cancer deaths now surpasses that of cancer deaths, particularly for young patients in the year after diagnosis.