Cure

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A cure is a substance or procedure that ends a medical condition, such as a medication, a surgical operation, a change in lifestyle or even a philosophical mindset that helps end a person's sufferings; or the state of being healed, or cured. The medical condition could be a disease, mental illness, genetic disorder, or simply a condition a person considers socially undesirable, such as baldness or lack of breast tissue.

Contents

An incurable disease may or may not be a terminal illness; conversely, a curable illness can still result in the patient's death.

The proportion of people with a disease that are cured by a given treatment, called the cure fraction or cure rate, is determined by comparing disease-free survival of treated people against a matched control group that never had the disease. [1]

Another way of determining the cure fraction and/or "cure time" is by measuring when the hazard rate in a diseased group of individuals returns to the hazard rate measured in the general population. [2] [3]

Inherent in the idea of a cure is the permanent end to the specific instance of the disease. [4] [5] When a person has the common cold, and then recovers from it, the person is said to be cured, even though the person might someday catch another cold. Conversely, a person that has successfully managed a disease, such as diabetes mellitus, so that it produces no undesirable symptoms for the moment, but without actually permanently ending it, is not cured.

Related concepts, whose meaning can differ, include response, remission and recovery.

Statistical model

In complex diseases, such as cancer, researchers rely on statistical comparisons of disease-free survival (DFS) of patients against matched, healthy control groups. This logically rigorous approach essentially equates indefinite remission with cure. [6] The comparison is usually made through the Kaplan-Meier estimator approach. [7]

The simplest cure rate model was published by Joseph Berkson and Robert P. Gage in 1952. [7] In this model, the survival at any given time is equal to those that are cured plus those that are not cured, but who have not yet died or, in the case of diseases that feature asymptomatic remissions, have not yet re-developed signs and symptoms of the disease. When all of the non-cured people have died or re-developed the disease, only the permanently cured members of the population will remain, and the DFS curve will be perfectly flat. The earliest point in time that the curve goes flat is the point at which all remaining disease-free survivors are declared to be permanently cured. If the curve never goes flat, then the disease is formally considered incurable (with the existing treatments).

The Berkson and Gage equation is

where is the proportion of people surviving at any given point in time, is the proportion that are permanently cured, and is an exponential curve that represents the survival of the non-cured people.

Cure rate curves can be determined through an analysis of the data. [7] The analysis allows the statistician to determine the proportion of people that are permanently cured by a given treatment, and also how long after treatment it is necessary to wait before declaring an asymptomatic individual to be cured. [3]

Several cure rate models exist, such as the expectation-maximization algorithm and Markov chain Monte Carlo model. [7] It is possible to use cure rate models to compare the efficacy of different treatments. [7] Generally, the survival curves are adjusted for the effects of normal aging on mortality, especially when diseases of older people are being studied. [8]

From the perspective of the patient, particularly one that has received a new treatment, the statistical model may be frustrating. [6] It may take many years to accumulate sufficient information to determine the point at which the DFS curve flattens (and therefore no more relapses are expected). Some diseases may be discovered to be technically incurable, but also to require treatment so infrequently as to be not materially different from a cure. Other diseases may prove to have multiple plateaus, so that what was once hailed as a "cure" results unexpectedly in very late relapses. Consequently, patients, parents and psychologists developed the notion of psychological cure, or the moment at which the patient decides that the treatment was sufficiently likely to be a cure as to be called a cure. [6] For example, a patient may declare himself to be "cured", and to determine to live his life as if the cure were definitely confirmed, immediately after treatment.

Response
Response is a partial reduction in symptoms after treatment.
Recovery
Recovery is a restoration of health or functioning. A person who has been cured may not be fully recovered, and a person who has recovered may not be cured, as in the case of a person in a temporary remission or who is an asymptomatic carrier for an infectious disease.
Prevention
Prevention is a way to avoid an injury, sickness, disability, or disease in the first place, and generally it will not help someone who is already ill (though there are exceptions). For instance, many babies and young children are vaccinated against polio (a highly infectious disease) and other infectious diseases, which prevents them from contracting polio. But the vaccination does not work on patients who already have polio. A treatment or cure is applied after a medical problem has already started.
Therapy
Therapy treats a problem, and may or may not lead to its cure. In incurable conditions, a treatment ameliorates the medical condition, often only for as long as the treatment is continued or for a short while after treatment is ended. For example, there is no cure for AIDS, but treatments are available to slow down the harm done by HIV and extend the treated person's life. Treatments don't always work. For example, chemotherapy is a treatment for cancer, but it may not work for every patient. In easily cured forms of cancer, such as childhood leukaemia's, testicular cancer and Hodgkin lymphoma, cure rates may approach 90%. [9] In other forms, treatment may be essentially impossible. A treatment need not be successful in 100% of patients to be considered curative. A given treatment may permanently cure only a small number of patients; so long as those patients are cured, the treatment is considered curative.

Examples

Cures can take the form of natural antibiotics (for bacterial infections), synthetic antibiotics such as the sulphonamides, or fluoroquinolones, antivirals (for a very few viral infections), antifungals, antitoxins, vitamins, gene therapy, surgery, chemotherapy, radiotherapy, and so on. Despite a number of cures being developed, the list of incurable diseases remains long.

1700s

Scurvy became curable (as well as preventable) with doses of vitamin C (for example, in limes) when James Lind published A Treatise on the Scurvy (1753). [10]

1890s

Antitoxins to diphtheria and tetanus toxins were produced by Emil Adolf von Behring and his colleagues from 1890 onwards. The use of diphtheria antitoxin for the treatment of diphtheria was regarded by The Lancet as the "most important advance of the [19th] Century in the medical treatment of acute infectious disease". [11] [12]

1930s

Sulphonamides become the first widely available cure for bacterial infections.[ citation needed ]

Antimalarials were first synthesized, [13] [14] [15] making malaria curable. [16]

1940s

Bacterial infections became curable with the development of antibiotics. [17]

2010s

Hepatitis C, a viral infection, became curable through treatment with antiviral medications. [18] [19]

See also

Related Research Articles

<span class="mw-page-title-main">Disease</span> Abnormal condition that negatively affects an organism

A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism and is not immediately due to any external injury. Diseases are often known to be medical conditions that are associated with specific signs and symptoms. A disease may be caused by external factors such as pathogens or by internal dysfunctions. For example, internal dysfunctions of the immune system can produce a variety of different diseases, including various forms of immunodeficiency, hypersensitivity, allergies, and autoimmune disorders.

<span class="mw-page-title-main">Leukemia</span> Blood cancers forming in the bone marrow

Leukemia is a group of blood cancers that usually begin in the bone marrow and result in high numbers of abnormal blood cells. These blood cells are not fully developed and are called blasts or leukemia cells. Symptoms may include bleeding and bruising, bone pain, fatigue, fever, and an increased risk of infections. These symptoms occur due to a lack of normal blood cells. Diagnosis is typically made by blood tests or bone marrow biopsy.

<span class="mw-page-title-main">Pelvic inflammatory disease</span> Infection of uterus, fallopian tubes, ovaries or the inner surface of pelvis

Pelvic inflammatory disease, also known as pelvic inflammatory disorder (PID), is an infection of the upper part of the female reproductive system, namely the uterus, fallopian tubes, and ovaries, and inside of the pelvis. Often, there may be no symptoms. Signs and symptoms, when present, may include lower abdominal pain, vaginal discharge, fever, burning with urination, pain with sex, bleeding after sex, or irregular menstruation. Untreated PID can result in long-term complications including infertility, ectopic pregnancy, chronic pelvic pain, and cancer.

<span class="mw-page-title-main">Infection</span> Invasion of an organisms body by pathogenic agents

An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable disease, is an illness resulting from an infection.

<span class="mw-page-title-main">Diphtheria</span> Bacterial disease

Diphtheria is an infection caused by the bacterium Corynebacterium diphtheriae. Most infections are asymptomatic or have a mild clinical course, but in some outbreaks the lethality rate approaches 10%. Signs and symptoms may vary from mild to severe and usually start two to five days after exposure. Symptoms often develop gradually, beginning with a sore throat and fever. In severe cases, a grey or white patch develops in the throat, which can block the airway and create a barking cough similar to what is observed in croup. The neck may also swell in part due to the enlargement of the facial lymph nodes. Diphtheria can also involve the skin, eyes or genitals, and can cause complications including myocarditis, inflammation of nerves, kidney problems, and bleeding problems due to low levels of platelets.

<span class="mw-page-title-main">Mycobacterial cervical lymphadenitis</span> Human medical condition

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<i>Corynebacterium diphtheriae</i> Species of prokaryote

Corynebacterium diphtheriae is the pathogenic bacterium that causes diphtheria. It is also known as the Klebs–Löffler bacillus, because it was discovered in 1884 by German bacteriologists Edwin Klebs (1834–1912) and Friedrich Löffler (1852–1915). The bacteria are usually harmless unless they are infected by a bacteriophage that carries a gene that gives rise to a toxin. This toxin causes the disease. Diphtheria is caused by the adhesion and infiltration of the bacteria into the mucosal layers of the body, primarily affecting the respiratory tract and the subsequent release of an endotoxin. The toxin has a localized effect on skin lesions, as well as a metastatic, proteolytic effects on other organ systems in severe infections. Originally a major cause of childhood mortality, diphtheria has been almost entirely eradicated due to the vigorous administration of the diphtheria vaccination in the 1910s.

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<span class="mw-page-title-main">Acute myeloid leukemia</span> Cancer of the myeloid line of blood cells

Acute myeloid leukemia (AML) is a cancer of the myeloid line of blood cells, characterized by the rapid growth of abnormal cells that build up in the bone marrow and blood and interfere with normal blood cell production. Symptoms may include feeling tired, shortness of breath, easy bruising and bleeding, and increased risk of infection. Occasionally, spread may occur to the brain, skin, or gums. As an acute leukemia, AML progresses rapidly, and is typically fatal within weeks or months if left untreated.

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<span class="mw-page-title-main">Gonorrhea</span> Sexually transmitted infection

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<span class="mw-page-title-main">Sexually transmitted infection</span> Infection transmitted through human sexual behavior

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<i>Corynebacterium ulcerans</i> Species of prokaryote

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References

  1. ↑ Fuller, Arlan F.; Griffiths, C. M. (1983). Gynecologic oncology . The Hague: M. Nijhoff. ISBN   0-89838-555-5.
  2. ↑ Lambert PC, Thompson JR, Weston CL, Dickman PW (2007). "Estimating and modeling the cure fraction in population-based cancer survival analysis". Biostatistics. 8 (3): 576–594. doi:10.1093/biostatistics/kxl030. PMID   17021277.
  3. 1 2 Smoll NR, Schaller K, Gautschi OP (2012). "The Cure Fraction of Glioblastoma Multiforme". Neuroepidemiology. 39 (1): 63–9. doi: 10.1159/000339319 . PMID   22776797.
  4. ↑ "Nearing a Cancer Cure?". Harvard Health Commentaries. 21 August 2006.
  5. ↑ "What's the Difference Between a Treatment and a Cure?". TeensHealth. Nemours. May 2018. Archived from the original on 2008-04-13.
  6. 1 2 3 Barnes E (December 2007). "Between remission and cure: patients, practitioners and the transformation of leukaemia in the late twentieth century". Chronic Illn. 3 (4): 253–64. doi:10.1177/1742395307085333. PMID   18083680. S2CID   13259230.
  7. 1 2 3 4 5 Friis, Robert H.; Chernick, Michael L. (2003). Introductory biostatistics for the health sciences: modern applications including bootstrap . New York: Wiley-Interscience. pp.  348–349. ISBN   0-471-41137-X.
  8. ↑ Tobias, Jeffrey M.; Souhami, Robert L. (2003). Cancer and its management. Oxford: Blackwell Science. p. 11. ISBN   0-632-05531-6.
  9. ↑ Saltus, Richard (Fall–Winter 2008). "What is a Cure?" (PDF). Paths of Progress. Vol. 17, no. 2. Boston: Dana-Farber Cancer Institute. p. 8. Retrieved August 2, 2020.
  10. ↑ Bartholomew, M (2002-11-01). "James Lind's Treatise of the Scurvy (1753)". Postgraduate Medical Journal. BMJ. 78 (925): 695–696. doi: 10.1136/pmj.78.925.695 . ISSN   0032-5473. PMC   1742547 . PMID   12496338.
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  12. ↑ Dolman, C.E. (1973). "Landmarks and pioneers in the control of diphtheria". Can. J. Public Health. 64 (4): 317–36. PMID   4581249.
  13. ↑ Krafts K, Hempelmann E, Skórska-Stania A (2012). "From methylene blue to chloroquine: a brief review of the development of an antimalarial therapy". Parasitol Res. 111 (1): 1–6. doi:10.1007/s00436-012-2886-x. PMID   22411634. S2CID   54526057.
  14. ↑ Hempelmann E. (2007). "Hemozoin biocrystallization in Plasmodium falciparum and the antimalarial activity of crystallization inhibitors". Parasitol Res. 100 (4): 671–76. doi:10.1007/s00436-006-0313-x. PMID   17111179. S2CID   30446678.
  15. ↑ Jensen M, Mehlhorn H (2009). "Seventy-five years of Resochin in the fight against malaria". Parasitol Res. 105 (3): 609–27. doi:10.1007/s00436-009-1524-8. PMID   19593586. S2CID   8037461.
  16. ↑ "Fact sheet about Malaria". World Health Organization. 14 January 2020. Retrieved 2020-08-04.
  17. ↑ "Battle of the Bugs: Fighting Antibiotic Resistance". U.S. Food and Drug Administration. 2016-05-04. Retrieved 2020-07-25. Just a few years after the first antibiotic, penicillin, became widely used in the late 1940s
  18. ↑ Wheeler, Regina Boyle (2018-10-15). "Is Hep C Curable?". WebMD. Retrieved 2019-02-12.
  19. ↑ "Hepatitis C - Symptoms and causes". Mayo Clinic. Retrieved 2020-07-25.
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