Editing Cancer (section)

== Prognosis ==
{{See also|Cancer survival rates|List of cancer mortality rates in the United States|Cancer survivor}}
[[File:Three measures of cancer mortality, OWID.svg|thumb|upright=1.15|Three measures of global cancer mortality from 1990 to 2017<ref>{{cite web |title=Three measures of cancer mortality |url=https://ourworldindata.org/grapher/cancer-deaths-rate-and-age-standardized-rate-index |website=Our World in Data |access-date=7 March 2020}}</ref>]]

Survival rates vary by cancer type and by the stage at which it is diagnosed, ranging from majority survival to complete mortality five years after diagnosis. Once a cancer has metastasized, prognosis normally becomes much worse. About half of patients receiving treatment for invasive cancer (excluding [[carcinoma in situ|carcinoma ''in situ'']] and non-melanoma skin cancers) die from that cancer or its treatment.<ref name=Epi11/> A majority of cancer deaths are due to metastases of the primary tumor.<ref>{{cite journal | vauthors = Tammela T, Sage J | title = Investigating Tumor Heterogeneity in Mouse Models | journal = Annual Review of Cancer Biology | volume = 4 | issue = 1 | pages = 99–119 | date = March 2020 | pmid = 34164589 | pmc = 8218894 | doi = 10.1146/annurev-cancerbio-030419-033413 | doi-access = free }}</ref>

Survival is worse in the [[developing world]],<ref name=Epi11/> partly because the types of cancer that are most common there are harder to treat than those associated with [[developed countries]].<ref>{{cite book |title=World Cancer Report 2014 |date=2014 |publisher=World Health Organization |isbn=978-92-832-0429-9 |url=http://www.searo.who.int/publications/bookstore/documents/9283204298/en/ |page=22 |archive-url=https://web.archive.org/web/20170712114430/http://www.searo.who.int/publications/bookstore/documents/9283204298/en/ |archive-date=12 July 2017}}</ref>

Those who survive cancer develop a second primary cancer at about twice the rate of those never diagnosed.<ref name=isbn1-55009-213-8/> 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.<ref name="isbn1-55009-213-8">{{cite book | veditors = Frei E, Kufe DW, Holland JF | vauthors = Rheingold S, Neugut A, Meadows A | title = Holland-Frei Cancer Medicine | edition = 6th | publisher = BC Decker | location = Hamilton, Ont | year = 2003 | page = [https://archive.org/details/cancermedicine60002unse/page/2399 2399] | isbn = 978-1-55009-213-4 | chapter-url = https://www.ncbi.nlm.nih.gov/books/NBK20948/#A41087 | chapter = 156: Secondary Cancers: Incidence, Risk Factors, and Management | url = https://archive.org/details/cancermedicine60002unse/page/2399 }}</ref>

Predicting short- or long-term survival depends on many factors. The most important are the cancer type and the patient's age and overall health. Those who are [[wikt:frailty|frail]] with other health problems have lower survival rates than otherwise healthy people. [[Centenarian]]s are unlikely to survive for five years even if treatment is successful. People who report a higher quality of life tend to survive longer.<ref>{{cite journal |vauthors=Montazeri A |title=Quality of life data as prognostic indicators of survival in cancer patients: an overview of the literature from 1982 to 2008 |journal=Health and Quality of Life Outcomes |volume=7 |page=102 |date=December 2009 |pmid=20030832 |pmc=2805623 |doi=10.1186/1477-7525-7-102 |author-link=Ali Montazeri |doi-access=free }}</ref> People with lower quality of life may be affected by [[major depressive disorder|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.{{Citation needed|date=January 2025}}

People with cancer have an increased risk of [[venous thromboembolism|blood clots in their veins]] which can be life-threatening.<ref name=":1">{{cite journal | vauthors = Akl EA, Kahale LA, Hakoum MB, Matar CF, Sperati F, Barba M, Yosuico VE, Terrenato I, Synnot A, Schünemann H | title = Parenteral anticoagulation in ambulatory patients with cancer | journal = The Cochrane Database of Systematic Reviews | volume = 2021 | pages = CD006652 | date = September 2017 | issue = 9 | pmid = 28892556 | pmc = 6419241 | doi = 10.1002/14651858.CD006652.pub5 }}</ref> The use of [[Anticoagulant|blood thinners]] such as [[heparin]] decrease the risk of blood clots but have not been shown to increase survival in people with cancer.<ref name=":1"/> People who take blood thinners also have an increased risk of bleeding.<ref name=":1"/>

Although extremely rare, some forms of cancer, even from an advanced stage, can heal spontaneously. This phenomenon is known as [[spontaneous remission]].<ref>{{cite journal | vauthors = Radha G, Lopus M | title = The spontaneous remission of cancer: Current insights and therapeutic significance | journal = Translational Oncology | volume = 14 | issue = 9 | page = 101166 | date = September 2021 | pmid = 34242964 | pmc = 8271173 | doi = 10.1016/j.tranon.2021.101166 }}</ref>