Cancer

: Cancer

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Cancers or `malignant neoplasm ' are a group of conditions in which the certain cells tend to divide at an uncontrollable or abnormal rate and invade other tissues (lying near and distant in the body ) by direct growth (invasion ) or by passage of the cells to the distant locations in the body through the blood or the lymph (distant metastasis . The uncontrolled growth is associated with a number of mutations (changes of the genetic material (DNA ) present within the cells . The genetic material present within the cell tends to control

all the cell functions and cell division . The word `cancer ' tends to bring about a lot of emotions and distress as it is often associated with death and dying In the last 30 years , there has been a lot of advancement in cancer sciences (Calman , Kenneth , C , 1978 . We have been able to develop better diagnostic tools and treatment interventions

In 2002-03 , the average age for diagnosis of cancer in the US was 67 years (NCI , 2006 . I of all cancers occurred in the first and second decades of life , less that 3 occurred in young adults , 20 occurred in the middle-aged individuals (35 to 54 years , and beyond 54 years the incidences were above 75 (NCI , 2006 . The incidences increased after the age of 65 years . After adjusting the incidence rates , cancer occurred in about 471 per 100 ,000 populations every year (NCI , 2006 According to the ethnic group , the incidences rates were the highest in African-Americans (326 /100000 in men and 191 /100000 in women , and the lowest in Asians (143 /100000 in men and 98 /100000 in women (NCI , 2006 Whites had an incidence of about 237 /100000 in men and 162 /100000 in women (NCI , 2006 . The incidences of cancer had increased in the US from 1930 to 1970 (Pillai , M . V , 2002 . Between 1975 and 2003 , the incidences of cancer have reduced in all ethnic groups and both sexes (NCI , 2006 . The decrease in the incidence has been slightly greater in women compared to men . The 5-year survival rates for cancer have improved over the years mainly because of the awareness , and improvements in the diagnostic and treatment techniques . The average 5-year survival rate is around 65 for the period between 1996 and 2002 (NCI , 2006 . The individual survival rate for race and sex is 66 .8 for white men 65 .9 for white women 59 .7 for black men and 53 .4 for black women (NCI , 2006 . Looking at the rates from 2001-2003 , about 41 of all individuals will be developing cancer of some part of their body during their lifetime . The probability of developing cancer is higher in men compared to women (e .g . between 50th to 70th birthday 21 men and 15 women will develop cancer (NCI , 2006 . The lifetime risk for developing cancer is slightly less that 1 in 2 for men and 1 in 3 for women (Lebersberg , Marguerite . S , 2005 . Men usually had higher incidences of prostrate cancer whereas females had higher incidences of breast cancer . In both sexes , the highest mortality rate was due to lung cancer (Lebersberg , Marguerite . S , 2005 . Current trends show that there is an increasing incidence of melanoma , whereas the incidences of colon cancer are decreasing (Lebersberg , Marguerite . S 2005 . Cancer was the second most common cause of death after cardiovascular diseases (Lebersberg , Marguerite . S , 2005 . In children , it is also the second most common cause of death after fatal accidents (Calman , Kenneth , C , 1978 . In 2004 , in the US , 1 .37 million people were diagnosed of cancer , and 563000 died (Lebersberg Marguerite . S , 2005

The exact cause of cancer has still not been understood . However several factors have been included for causing cancer . These include viral causes , chemical causes , genetic causes , physical causes , hormonal causes , etc

People often exposed to radioactive substances are at a higher risk of developing cancer . Radiations that can cause cancer include electromagnetic rays and particulate rays (Yuspa , S . H , 1997 Electromagnetic rays include ultraviolet , X-rays and gamma rays . These rays carry energy so as to displace electrons from atoms (Calman Kenneth , C , 1978 . They get converted into ions which are highly reactive . They can react with any cell and damage the genetic material In low-doses , the cells can repair themselves . However , in higher doses , the damages become irreparable . The DNA strands begin to degenerate , and as they tend to rapidly proliferate , the damage is uncontrollable . During radiotherapy the rate of administration of dose plays a very important role (Calman , Kenneth , C , 1978 . Several chemicals are also associated with cancer , as the incidences are higher in people that are in contact with them . The chemical can either be genotoxic , non-genotoxic or both . Genotoxic substance has higher reactivity and can be broken down to reactive by-products by the host On the other hand , non-genotoxic substances do not damage the genes , but act in other mechanism (e .g . pesticides and herbicides . Studies have shown that they are carcinogenic in animals (Calman , Kenneth , C , 1978 Most of the chemical carcinogens are also mutagens (i .e . they cause mutation of genes . Viruses are also associated with cancer worldwide DNA viruses (such as hepatitis B virus , human papilloma virus , and Epstein Barr Virus ) were responsible for most cancer than the RNA virus (such as Retroviridae (Poewchla , E . M , 1997 . Many cancers such as hepatocellular carcinoma , cervical carcinoma , Burkett 's lymphoma Kaposi 's sarcoma are caused by viruses (Calman , Kenneth , C , 1978 Individuals with cancer often show changes in the chromosome pattern This chromosome pattern may be due to the effect rather than the cause of cancer . However , looking at the familial occurrences of cancer , it is clear the there is some hereditary involvement . Down 's syndrome is a condition in which the incidences of developing leukaemia are increase (Calman , Kenneth , C , 1978 . In this condition , there is a chromosomal abnormality . In Fanconi 's anemia , Bloom 's disease and ataxia telangiectsia , the risk of the chromosomes fragmenting is high (Calman Kenneth , C , 1978 . These individuals hence have an associated risk of developing certain cancers (leukemia . Hormonal factors may also be associated with cancer , through observations made clinically epidemiologically and through studies (Henderson , B . E , 1997 . Breast cancer is associated with estrogen stimulation and also simultaneous presence of progesterone . The risk factors for endometrial cancer include hormone replacement therapy , obesity , sequential oral contraceptives and late menopause (Henderson , B . E , 1997 . The protective factors for endometrial cancer include pregnancy an oral contraceptives . Ovarian cancer on the other hand could be associated with gondotrophins , which tend to exert its effect indirectly or through ovarian epithelial cells (Henderson , B . E , 1997

Cancer can occur in almost any part of the body . One of the main characteristics of any advanced form of cancer is a rundown condition known as `cachexia (Calman , Kenneth , C , 1978 . The individual develops tiredness , anorexia , weakness and weight loss . This may be associated with several biochemical abnormalities (Calman , Kenneth , C 1978 . Cancer can also demonstrate manifestations on the skin . Often this is the most recognized symptom , and physicians who observe many skin manifestations may want to look for any tumor present in the body Dermatomyosistis and icthyosis occur following cancer of the breast lungs , digestive tract , and lymphomas (Calman , Kenneth , C , 1978 Endocrine-related tumors may cause disturbances in hair growth and subcutaneous fat deposition . Cancers can also present with pruritis and skin rashes . Inversely , skin cancers can also present with symptoms in various internal organs such as the colon (Gloster , H . M . Jr , 2006 Cancer can also affect the muscles and the bones . Often muscle weakness , degeneration of the muscles , bone tumors , pathological fractures , bone pain , etc develop in cancers (Calman , Kenneth , C 1978 . Frequently , cancer tends to affect the brain and nerve cells Portions of the brain may be destroyed (subacute cerebellar degeneration ) in cancer resulting in ataxia , difficulty in walking , etc (Calman , Kenneth , C , 1978 . Tumor cells often spread to the nerves (Lebersberg , Marguerite . S , 2005 . Cancers can also involve the blood cells . Usually this manifestation is common following administration of medications /radiotherapy (Lebersberg , Marguerite . S , 2005 . The blood cells may be destroyed leading to anemia (weakness , palpitations and tiredness , thrombocytopenia (excessive bleeding and bruises ) and infections (due to destruction of the WBC 's . Infection may also be associated with presence of metastasis in various parts of the body (such as lungs , urinary tract ) which increase the risk of lower the ability to fight infection and decreased action of the body defense mechanism . About one-third of all cancer patients ' die of infections Sometimes , the patient can develop unusual infections caused by fungi bacteria or viruses (Calman , Kenneth , C , 1978

Several attempts and techniques have been developed to treat or reduce the ill-effects of cancer . These include chemotherapy , surgery radiotherapy , biological therapy , angiogenesis inhibitors , cryotheraphy gene therapy , bone marrow transplantation and photodynamic therapy which may have to be given alone or in combination (NCI , 1996 . The physician , before starting any treatment , should define the goal of the treatment and makes sure that the benefits outweigh the risks involved (Djulbegovic , B , 1997 . Patients often seek cancer treatment in to cure it . However , a cure may not always be possible . Several factors such as size and nature of the tumor , spread to other structures of the body , general health of the patient , etc , tend to affect the treatment-decision (Djulbegovic , B , 1997 . The patient may also have several associated symptoms which have to be treated , individually . The patient 's treatment should be continuously monitored , and any problem should be treated appropriately (Djulbegovic , B , 1997 . Chemotherapy is the process of treating cancer using certain medications that destroy the cancerous cells . These drugs stop the rapidly dividing cancer cells from multiplying . They may also damage the healthy cells of the body However , since the healthy cells have a normal genetic material , repair is possible (NCI , 1996 . Radiotherapy is a process in which high-energy waves are being utilized to destroy cancer cells . It is required either to stop the growth of cancer or shrink the size of the tumor . Radiation can be given from an external source or from a source implanted in the body (brachytherapy . Sometimes following removal of the tumor , a large dose of radiation is given to prevent the tumor cells from multiplying again (intra-operative radiation therapy (NCI , 1996 . Prophylactic cranial irradiation is a treatment in which radiation is delivered to the brain in to prevent the tumor cells from multiplying to the brain (NCI , 1996 . Surgery is also performed to remove localized tumors or their metastases . Following surgery the surrounding tissues may have to be removed along with the regional lymph nodes in to prevent any relapses . Cryotheraphy is a procedure in which extreme cold is utilized to treat cancer . It can be used to treat external tumor (e .g skin cancers , low-grade malignant tumors , pre-cancerous conditions and non-cancerous diss (NCI , 1996 . Angiogenesis is a process in which the blood supply to a tumor is reduced by administering certain agents known as `angiogenesis inhibitors . This process is not being yet tried in human beings , but is thoroughly being evaluated through clinical trials to determine its efficacy and safety (NCI , 1996 . Biological therapy is a procedure in which stimulates the body 's defense mechanism (immune system ) to fight cancers . Some of these therapies have been found to be effective in up to 40 of certain lymphomas (Pillai , M . V 2002 . Bone marrow transplantation is a procedure in which suitable bone marrow tissue (that is responsible for the production of blood cells ) are transferred from a donor . It is done following destruction of the diseased bone marrow due to cancer . Bone marrow transplantation may be performed after radiotherapy or chemotherapy which seriously affects the functioning of the bone marrow tissues (NCI , 1996 Photodynamic therapy is a procedure in which a photosensitizing agent is utilized along with a specific kind of light to destroy a tumor following exposure to high levels of oxygen (NCI , 1996

References

Brawley , O . W , and Kramer , B . S . Prevention and Early Detection of Cancer ' Harrison 's Principles of Internal Medicine , Ed . Braunwald , E Fauci , A , Kasper , D , Hauser , S , Longo , D , and Jameson , J . 2004 . New York : McGraw-Hill

Calman , Kenneth , C , and Paul , John . An Introduction to Cancer Medicine London : The Macmillan Press , 1978

Djulbegovic , B . principles of Reasoning and Decision Making in Oncology ' Decision Making In Oncology : Evidence-Based management , Ed Djulbegovic , B , and Sullivan , D . M . 1997 . New York : Churchill Livingstone

Gloster , H . M . Jr Neal , K (2006 . Skin cancer in skin of color J Am Acad Dermatol . 55 (5 (2006 : 741-760 . HYPERLINK "http /www .ncbi .nlm .nih .gov /entrez /query .fcgi ?db pubmed cmd Retrieve do pt AbstractPlus list_uids query_hl 1 itool pubmed_DocSum http /www .ncbi .nlm .nih .gov /entrez /query .fcgi ?db pubmed cmd Retrieve dop t AbstractPlus list_uids query_hl 1 itool pubmed_DocSum

Henderson , B . E , Bernstein , L Ross , R . Etilogy of Cancer-Hormonal Factors ' Cancer : Principles and Practice of Oncology , Ed . DeVita Jr V . T , Hellman , S . and Rosenberb , S . A . 1997 . Philadelphia : Lippincott Raven

Lebersberg , Marguerite . S . Psycho-oncology . Kaplan and Sadock 's Comprehensive Textbook of Psychiatry . Ed . Sadock , B . J . and Sadock , V A . Philadelphia : Lippincott , Williams and Wilkins , 2005

National Cancer Institute . Types of Treatment ' Cancer s . 2006 NCI . 4 Dec . 2006 HYPERLINK "http /www .cancer .gov /cancers /treatment /types-of-treatment http /www .cancer .gov /cancers /treatment /types-of-treatment

National Cancer Institute . Cancer of All Sites ' SEER Cancer Stat Fact Sheets . 2006 . NCI . 4 Dec . 2006 HYPERLINK "http /seer .cancer .gov /statfacts /html /all .html http /seer .cancer .gov /statfacts /html /all .html

Pillai , M . V . and Chatta , G . Cancer in the Elderly ' Primer on Geriatric Care : A Clinical Approach to the Older Patient Ed . Rosenblatt D . E . and Natarajan , V . S . Cochin : Castle Printers , 2002 . 235-266

Poewchla , E . M , Wong-Stall , F . Etiology of Cancer-RNA Viruses Cancer : Principles and Practice of Oncology , Ed . DeVita Jr . V . T Hellman , S . and Rosenberb , S . A . 1997 . Philadelphia : Lippincott Raven

Trichopaulos , D , Lipsworth , L , Petridou , E , and Adami . H . O Epidemiology of Cancer ' Cancer : Principles and Practice of Oncology Ed . DeVita Jr . V . T , Hellman , S . and Rosenberb , S . A . 1997 Philadelphia : Lippincott Raven

Yuspa , S . H , and Shields ,

. G . Etiology of Cancer-Physical Factors ' Cancer : Principles and Practice of Oncology , Ed . DeVita Jr V . T , Hellman , S . and Rosenberb , S . A . 1997 . Philadelphia : Lippincott Raven

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Cancer

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