Cancer Survivors and Causes of Death

At the American Association of Cancer Research annual meeting, held in Chicago, IL, on March 31-April 4, 2012, Ning and colleagues from Virginia Commonwealth University presented interesting data on cancer survivorship. Their presentation was titled “Cause of Death in Cancer Survivors” (abstract LB-339; available at http://bit.ly/HQHPFH). My first thought when I saw the title was that cancer survivors don’t die of cancer. So what do they die from?

The researchers noted that cancer treatment has improved over the past few decades and cancer survivors are now living much longer. They identified 1,807 cancer survivors from the National Health and Nutrition Examination Survey (NHANES) III 1988-1994 and NHANES 1999- 2004. Cancer survivors were identified if they self-reported having ever been told that they had cancer or a malignancy of any kind; however, those with skin cancer and individuals under 18 years of age were excluded from the study. Causes of death were based on the National Death Index (NDI). All participants were followed from the start date of the survey to December 31, 2006, by linking National Death Index (NDI) death certificate records. The follow-up time ranged from 0 to 17.3 years and 776 participants died during this period. The causes of death were classified into 3 categories: related with cancer, indeterminate, and not related with cancer. The causes of death were then stratified by the duration since the diagnosis of cancer, which was calculated as follow-up time plus years between age at NHANES survey and age when being diagnosed with cancer. Commonly reported types of cancer were prostate (n=165), breast (n=141) and colorectal cancer (n=117).

During the course of the 17+ year study, 776 cancer survivors died — 51% from cancer and 49% from other causes. Cardiovascular disease was the primary cause of non-cancer deaths, and respiratory disease was another common cause. The researchers found that the longer patients survived after their initial cancer diagnosis, the more likely they were to die from another disease; 32.8% died from another condition within 5 years of diagnosis compared with 62.7% after 20 years.

With nearly half of cancer survivors dying from other causes, the implications of the study are clear. Oncology clinicians need to not only monitor cancer survivors for long term effects of treatment, we must also monitor our patients for diseases that commonly occur as people age, such as heart disease. We also need to monitor for other commonly occurring diseases, such as diabetes. With close monitoring, cancer survivors may one day also be heart disease survivors and live long, healthy lives.