Spontaneous remission, also called spontaneous healing or spontaneous regression, is an unexpected improvement or cure from a disease that usually progresses. These terms are commonly used for unexpected transient or final improvements in

cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...

. Spontaneous remissions concern cancers of the haematopoietic system (blood cancer, e.g. leukemia), while spontaneous regressions concern palpable tumors; however, both terms are often used interchangeably.

Definition

The spontaneous regression and remission from cancer was defined by Everson and Cole in their 1966 book as "the partial or complete disappearance of a malignant tumour in the absence of all treatment, or in the presence of therapy which is considered inadequate to exert significant influence on neoplastic disease."Everson T., Cole W. (1968) ''Spontaneous Regression of Cancer'' Philadelphia, JB Saunder & Co (Book)

Frequency of spontaneous regression in cancer

It has long been assumed that spontaneous regressions, let alone cures, from cancer are rare phenomena, and that some forms of cancer are more prone to unexpected courses (

melanoma Melanoma, also redundantly known as malignant melanoma, is a type of skin cancer that develops from the pigment-producing cells known as melanocytes. Melanomas typically occur in the skin, but may rarely occur in the mouth, intestines, or eye ( ...

neuroblastoma Neuroblastoma (NB) is a type of cancer that forms in certain types of nerve tissue. It most frequently starts from one of the adrenal glands but can also develop in the neck, chest, abdomen, or spine. Symptoms may include bone pain, a lump in ...

lymphoma Lymphoma is a group of blood and lymph tumors that develop from lymphocytes (a type of white blood cell). In current usage the name usually refers to just the cancerous versions rather than all such tumours. Signs and symptoms may include en ...

) than others (

carcinoma Carcinoma is a malignancy that develops from epithelial cells. Specifically, a carcinoma is a cancer that begins in a tissue that lines the inner or outer surfaces of the body, and that arises from cells originating in the endodermal, mesoderm ...

). Frequency was estimated to be about 1 in 100,000 cancers; however, this proportion might be an under- or an overestimate. For one, not all cases of spontaneous regression can be apprehended, either because the case was not well documented or the physician was not willing to publish, or simply because the patient ceased to attend a clinic any more. On the other hand, for the past 100 years almost all cancer patients have received some form of treatment, and the influence of that treatment cannot always be excluded. It is likely that the frequency of spontaneous regression in small tumors has been drastically underrated. In a carefully designed study on mammography it was found that 22% of all breast cancer cases underwent spontaneous regression.

Causes

Everson and Cole offered as explanation for spontaneous regression from cancer: Challis and Stam, even more at a loss, concluded in 1989, "In summary, we are left to conclude that, although a great number of interesting and unusual cases continue to be published annually, there is still little conclusive data that explains the occurrence of spontaneous regression."

Apoptosis Apoptosis (from grc, ἀπόπτωσις, apóptōsis, 'falling off') is a form of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes ( morphology) and death. These changes in ...

(programmed cell death) and

angiogenesis Angiogenesis is the physiological process through which new blood vessels form from pre-existing vessels, formed in the earlier stage of vasculogenesis. Angiogenesis continues the growth of the vasculature by processes of sprouting and splittin ...

(growth of new blood vessels) are sometimes discussed as possible causes of spontaneous regression. But both mechanisms need appropriate biochemical triggers and cannot initiate on their own. Indeed, in many cancer cells apoptosis is defective, and angiogenesis is activated, both of these effects being caused by mutations in cancer cells; cancer exists because both mechanisms are malfunctioning. There are several case reports of spontaneous regressions from cancer occurring after a

fever Fever, also referred to as pyrexia, is defined as having a temperature above the normal range due to an increase in the body's temperature set point. There is not a single agreed-upon upper limit for normal temperature with sources using val ...

brought on by

infection 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 di ...

, suggesting a possible causal connection. If this coincidence in time would be a causal connection, it should as well precipitate as prophylactic effect, i.e. feverish infections should lower the risk to develop cancer later. This could be confirmed by collecting epidemiological studies.

Reviews

*Rohdenburg (1918) summarized 185 spontaneous regressions *Fauvet reported 202 cases between 1960 and 1964 *Boyd reported 98 cases in 1966 *Everson and Cole described 176 cases between 1900 and 1960 *Challis summarized 489 cases between 1900 and 1987 *O'Regan Brendan, Carlyle Hirschberg collected over 3,500 references from the medical literature *Hobohm, in a

meta-analysis A meta-analysis is a statistical analysis that combines the results of multiple scientific studies. Meta-analyses can be performed when there are multiple scientific studies addressing the same question, with each individual study reporting m ...

, investigated about 1000 cases *Turner, in a

qualitative research Qualitative research is a type of research that aims to gather and analyse non-numerical (descriptive) data in order to gain an understanding of individuals' social reality, including understanding their attitudes, beliefs, and motivation. This ...

study, conducted interviews with 20 patients with spontaneous remissions * ''Surviving Against All Odds'' - re sole survivor in "''a gamma interferon study''"

References

External links