A majority of cancer deaths are due to metastases of the primary tumor.Survival is worse in the developing world, partly because the types of cancer that are most common there are harder to treat than those associated with developed countries.Those who survive cancer develop a second primary cancer at about twice the rate of those never diagnosed. The increased risk is believed to be due to the random chance of developing any cancer, the likelihood of surviving the first cancer, the same risk factors that produced the first cancer, unwanted side effects of treating the first cancer (particularly radiation therapy), and better compliance with screening.Predicting short- or long-term survival depends on many factors. The most important are the cancer type and the patients age and overall health. Those who are frail with other health problems have lower survival rates than otherwise healthy people. Centenarians are unlikely to survive for five years even if treatment is successful. People who report a higher quality of life tend to survive longer. People with lower quality of life may be affected by depression and other complications and/or disease progression that both impairs quality and quantity of life. Additionally, patients with worse prognoses may be depressed or report poorer quality of life because they perceive that their condition is likely to be fatal. People with cancer have an increased risk of blood clots in their veins which can be life-threatening.
The precise nature of the genetic damage and the genes that are affected by it. The consequences of those genetic changes on the biology of the cell, both in generating the defining properties of a cancer cell and in facilitating additional genetic events that lead to further progression of the cancer.The improved understanding of molecular biology and cellular biology due to cancer research has led to new treatments for cancer since US President Richard Nixon declared the "War on Cancer" in 1971. Since then, the country has spent over $200 billion on cancer research, including resources from public and private sectors. The cancer death rate (adjusting for size and age of the population) declined by five percent between 1950 and 2005.Competition for financial resources appears to have suppressed the creativity, cooperation, risk-taking and original thinking required to make fundamental discoveries, unduly favoring low-risk research into small incremental advancements over riskier, more innovative research. Other consequences of competition appear to be many studies with dramatic claims whose results cannot be replicated and perverse incentives that encourage grantee institutions to grow without making sufficient investments in their own faculty and facilities.Virotherapy, which uses convert viruses, is being studied. In the wake of the COVID-19 pandemic, there has been a worry that cancer research and treatment are slowing down. Pregnancy
Cancer affects approximately 1 in 1,000 pregnant women.