Health Reports

A Canadian peer-reviewed journal of population health and health services research

November 2014

Adjusting relative survival estimates for cancer mortality in the general population

by Larry F. Ellison

For cancer, relative survival is defined as the ratio of the observed (absolute) survival in a group of people diagnosed with cancer to the expected survival of a comparable group—free of the cancer under study—in the general population. In theory, the relative survival ratio (RSR) provides an estimate of the difference between the all-cause mortality of those diagnosed with cancer and the mortality that would be expected in the absence of cancer (the excess mortality due to cancer). In practical applications, however, expected survival is typically estimated from general population life tables. Because these estimates include people previously diagnosed with cancer, they underestimate expected survival, and hence, overestimate relative survival.


Parkinson's disease: Prevalence, diagnosis and impact

by Suzy L. Wong, Heather Gilmour and Pamela L. Ramage-Morin

Parkinson's disease is the second most common neurodegenerative disorder after Alzheimer's disease. It results from the loss of cells in the brain that produce dopamine, a chemical that controls the body's movements. As dopamine decreases, tremors can develop, muscle movements become slower and more rigid, and reflexes become impaired contributing to a loss of balance. Other symptoms may include depression, anxiety, emotional changes, cognitive impairment, difficulty swallowing, chewing and speaking, masked facial expressions, urinary problems, constipation, fatigue, and sleep problems. Parkinson's disease is a chronic, progressive disorder, meaning that symptoms continue and worsen over time. The cause is unknown, and although there is currently no cure, medications and other treatment options are available to manage its symptoms.

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