Five-year survival rate

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The five-year survival rate is a type of survival rate for estimating the prognosis of a particular disease, normally calculated from the point of diagnosis. [1] Lead time bias from earlier diagnosis can affect interpretation of the five-year survival rate. [2]

Contents

There are absolute and relative survival rates, but the latter are more useful and commonly used.

Relative and absolute rates

Five-year relative survival rates are more commonly cited in cancer statistics. [3] Five-year absolute survival rates may sometimes also be cited. [4]

The fact that relative survival rates above 100% were estimated for some groups of patients appears counterintuitive on first view. It is unlikely that occurrence of prostate cancer would increase chances of survival, compared to the general population. A more plausible explanation is that the pattern reflects a selection effect of PSA screening, as screening tests tend to be used less often by socially disadvantaged population groups, who, in general, also have higher mortality. [5]

Uses

Five-year survival rates can be used to compare the effectiveness of treatments. Use of five-year survival statistics is more useful in aggressive diseases that have a shorter life expectancy following diagnosis, such as lung cancer, and less useful in cases with a long life expectancy, such as prostate cancer.

Improvements in rates are sometimes attributed to improvements in diagnosis rather than to improvements in prognosis. [6]

To compare treatments independently from diagnostics, it may be better to consider survival from reaching a certain stage of the disease or its treatment.

Analysis performed against the Surveillance, Epidemiology, and End Results database (SEER) facilitates calculation of five-year survival rates. [7] [8]

References

  1. "Cancer survival rate: A tool to understand your prognosis - MayoClinic.com" . Retrieved 2009-10-11.
  2. Gordis, Leon (2008). Epidemiology: with STUDENT CONSULT Online Access. Philadelphia: Saunders. p. 318. ISBN   1-4160-4002-1.
  3. Varricchio, Claudette G. (2004). A cancer source book for nurses. Boston: Jones and Bartlett Publishers. p. 30. ISBN   0-7637-3276-1.
  4. "ACS : How Is Colorectal Cancer Staged?" . Retrieved 2009-10-11.
  5. 1 2 Brenner H, Arndt V (January 20, 2005). "Long-term survival rates of patients with prostate cancer in the prostate-specific antigen screening era: population-based estimates for the year 2000 by period analysis" (PDF). J Clin Oncol . 23 (3): 441–7. doi:10.1200/JCO.2005.11.148. PMID   15572727.
  6. Welch HG, Schwartz LM, Woloshin S (June 2000). "Are increasing 5-year survival rates evidence of success against cancer?". JAMA. 283 (22): 2975–8. doi:10.1001/jama.283.22.2975. PMID   10865276.
  7. Gloeckler Ries LA, Reichman ME, Lewis DR, Hankey BF, Edwards BK (2003). "Cancer survival and incidence from the Surveillance, Epidemiology, and End Results (SEER) program". Oncologist. 8 (6): 541–52. doi:10.1634/theoncologist.8-6-541. PMID   14657533.
  8. Cosetti M, Yu GP, Schantz SP (April 2008). "Five-year survival rates and time trends of laryngeal cancer in the US population". Arch. Otolaryngol. Head Neck Surg. 134 (4): 370–9. doi:10.1001/archotol.134.4.370. PMID   18427002.[ permanent dead link ]