Cancer Symptoms and Causes of Cancer

cancer

cancer symptoms and types of cancer

Cancer is a group of diseases characterized by the uncontrolled growth and spread of abnormal cells. If the spread is not con- trolled, it can result in death. Cancer is caused by both external factors (tobacco, infectious organisms, chemicals, and radia- tion) and internal factors (inherited mutations, hormones, immune conditions, and mutations that occur from metabo- lism). These causal factors may act together or in sequence to initiate or promote the development of cancer. Ten or more years often pass between exposure to external factors and detectable cancer. Cancer is treated with surgery, radiation, chemotherapy, hormone therapy, immune therapy, and targeted theraphy.Cancer is caused by abnormal cells that grow quickly. It is normal for your body to replace old cells with new ones, but cancer cells grow too fast.Some cancer cells may form growths called tumors. All tumors increase in size, but some tumors grow quickly, others slowly.

Types of Tumors

• Sometimes tumors are not cancerous. These are called benign tumors. They are made up of cells much like those of healthy tissue.
This kind of tumor stays in one area and does not spread to healthy tissues and organs.
• Cancer tumors are also called malignant tumors. Cancer from these tumors spread through the blood and lymph systems to other parts of the body. When cancer spreads, it is called metastasis. Cancer cells travel through the body from the tumor, called the primary site, to other parts of the body.

Types of Cancer

There are many kinds of cancers.
• Carcinoma is the most common type of cancer. Lung, colon, breast and ovarian cancers are often this type of cancer.
• Sarcoma is found in bone, cartilage, fat and muscle.
• Lymphoma begins in the lymph nodes of the body’s immune system. They include Hodgkin’s and Non-Hodgkin’s Lymphomas.
• Leukemia starts in the blood cells that grow in the bone marrow and are found in large numbers in the bloodstream.

Signs of Cancer

Signs of cancer depend on the type and location of the tumor. With some cancers, there may not be any signs until the tumor is large.
Common signs include:
• Feeling very tired
• Weight loss that occurs without knowing why
• Fever, chills or night sweats
• Lack of hunger
• Physical discomfort or pain
• Coughing, shortness of breath or chest pain
• Diarrhea, constipation or blood in the stool
When cancer is found, tests will be done to see if the cancer has spread to other parts of your body. Scans, x-rays and blood tests may be needed. Your Care Your doctor will decide what care is needed based on:
• The type of cancer
• How fast the cancer is growing
• Whether the cancer has spread to other parts of your body
• Your age and overall health
The most common cancer treatments are:
• Surgery to remove the tumor and nearby tissue
• Radiation in controlled amounts to shrink or destroy the tumor and cancer cells
• Chemotherapy medicine to slow the growth or destroy cancer cells
• Other medicines to treat side effects and help you heal better

Prevention of cancer

You can reduce your risk of cancer by:
• Not smoking or using tobacco.
• Using sunscreen, hats and clothing to protect your skin when outside.
• Limiting the amount of alcohol you drink.
• Limiting the amount of high fat foods you eat, especially from animal sources.
• Eating plenty of fruits, vegetables and high fiber foods.
• Being physically active.
• Seeing your doctor each year. Cancer screenings may help find cancers at their early, most treatable stages.

Causes of cancer and its prevention Measures

A substantial proportion of cancers could be prevented. All cancers caused by cigarette smoking and heavy use of alcohol could be prevented completely. In 2014, almost 176,000 of the estimated 585,720 cancer deaths will be caused by tobacco use. In addition, the World Cancer Research Fund has estimated that up to one-third of the cancer cases that occur in economically developed countries like the US are related to overweight or obesity, physical inactivity, and/or poor nutrition, and thus could also be prevented. Certain cancers are related to infectious agents, such as human papillomavirus (HPV), hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), and Helicobacter pylori (H. pylori). Many of these cancers could be prevented through behavioral changes or the use of protective vaccinations or antibiotic treatments. Many of the more than 3 million skin cancer cases that are diagnosed annu- ally could be prevented by protecting skin from excessive sun exposure and avoiding indoor tanning. Screening offers the ability for secondary prevention by detect- ing cancer early, before symptoms appear. Early detection usually results in less extensive treatment and better outcomes. Screening is known to reduce mortality for cancers of the breast, colon, rectum, cervix, and lung (among heavy smokers). A heightened awareness of changes in the breast, skin, or testi- cles may also result in detection of tumors at earlier stages. Screening for colorectal and cervical cancers can actually pre- vent cancer by allowing for the detection and removal of pre-cancerous lesions.

benefit from treatment with an aromatase inhibitor (e.g., letro- zole, anastrozole, or exemestane) in addition to, or instead of, tamoxifen. For women whose cancer tests positive for HER2/neu, several therapies are available that target the growth-promoting protein HER2. The US Food and Drug Administration (FDA) revoked approval of bevacizumab (Avas- tin) for the treatment of metastatic breast cancer in 2011 because of evidence showing minimal benefit and potentially dangerous side effects. While some cases of ductal carcinoma in situ (DCIS) will pro- gress to invasive cancer, many will not. However, because there is currently no way to distinguish which lesions will go on to cause harm, surgery is recommended for all patients.
Treatment options for DCIS include breast-conserving surgery with radia- tion therapy or mastectomy; if the tumor is hormone receptor-positive, surgery may be followed by treatment with tamoxifen. Removal of axillary lymph nodes is not generally needed, but a sentinel lymph node procedure may be performed with a mastectomy. A report by a panel of experts convened by the National Institutes of Health concluded that in light of the noninvasive nature and favorable prognosis of DCIS, the pri- mary goal of future research should be the development of risk categories so each patient can receive the minimum treatment necessary for a successful outcome. Survival: Overall, 61% of breast cancer cases are diagnosed at a localized stage (no spread to lymph nodes or other locations out- side the breast), for which the 5-year relative survival rate is 99%. If the cancer has spread to tissues or lymph nodes under the arm (regional stage), the survival rate is 84%. If the spread is to lymph nodes around the collarbone or to distant lymph nodes or organs (distant stage), the survival rate falls to 24%. For all stages com- bined, relative survival rates at 10 and 15 years after diagnosis are 83% and 78%, respectively.
Caution should be used when interpreting long-term survival rates because they represent patients who were diagnosed many years ago and do not reflect recent advances in detection and treatment. For example, 15-year relative survival is based on patients diagnosed as early as 1992. There are large differences in breast cancer survival by race; for all stages combined, the 5-year survival rate is 90% for white women and 79% for African American women. Many studies have shown that being overweight adversely affects survival for postmenopausal women with breast cancer. In addition, breast cancer survivors who are more physically active, particularly after diagnosis, are less likely to die from breast cancer, or other causes, than those who are inactive. For more information about breast cancer, see the American Cancer Society’s Breast Cancer Facts & Figures, available online at cancer.org/statistics.

Who Is at Risk of Developing Cancer?

Anyone can develop cancer. Since the risk of being diagnosed with cancer increases with age, most cases occur in adults who are middle aged or older. About 77% of all cancers are diagnosed in people 55 years of age and older. Cancer researchers use the word “risk” in different ways, most commonly expressing risk as lifetime risk or relative risk. In this publication, lifetime risk refers to the probability that an individual will develop or die from cancer over the course of a lifetime. In the US, men have slightly less than a 1 in 2 lifetime risk of developing cancer; for women, the risk is a little more than 1 in 3. It is important to note that these probabilities are estimated based on the overall experience of the general population. Individuals within the population may have higher or lower risk because of differences in exposures (e.g., smoking), and/or genetic susceptibility.
Relative risk is a measure of the strength of the relationship between a risk factor and cancer. It compares the risk of developing cancer in people with a certain exposure or trait to the risk in people who do not have this characteristic. For example, male smokers are about 23 times more likely to develop lung cancer than nonsmokers, so their relative risk is 23. Most relative risks are not this large.
For example, women who have a first-degree relative (mother, sister, or daughter) with a history of breast can- cer are about twice as likely to develop breast cancer as women who do not have this family history. All cancers involve the malfunction of genes that control cell growth and division. Only a small proportion of cancers are strongly hereditary, in that an inherited genetic alteration confers a very high risk for developing cancer. Inherited factors play a larger role in determining risk for some cancers (e.g., colorec- tal, breast, and prostate) than for others.
It is now thought that many familial cancers arise from the interplay between com- mon gene variations and lifestyle/environmental risk factors. However, most cancers do not result from inherited genes but from damage to genes occurring during a person’s lifetime. Genetic damage may result from internal factors, such as hormones or the metabolism of nutrients within cells, or external factors, such as tobacco, or excessive exposure to chemicals, sunlight, or ionizing radiation.

How Is Cancer Staged?

Staging describes the extent or spread of cancer at the time of diagnosis. Proper staging is essential in determining the choice of therapy and in assessing prognosis. A cancer’s stage is based on the size or extent of the primary (main) tumor and whether it has spread to nearby lymph nodes or other areas of the body. A number of different staging systems are used to classify cancer. A system of summary staging is used for descriptive and statisti- cal analysis of tumor registry data. If cancer cells are present only in the layer of cells where they developed and have not spread, the stage is in situ. If cancer cells have penetrated beyond.

What Are the Costs of Cancer?

The National Institutes of Health (NIH) estimates that the over- all costs of cancer in 2009 were $216.6 billion: $86.6 billion for direct medical costs (total of all health expenditures) and $130.0 billion for indirect mortality costs (cost of lost productivity due to premature death). PLEASE NOTE: These numbers are not comparable to those published in Cancer Facts & Figures prior to 2012 because in 2011, the NIH began calculating these estimates using a different data source: the Medical Expenditure Panel Survey (MEPS) of the Agency for Healthcare Research and Qual- ity. The MEPS estimates are based on more current, nationally representative data and are used extensively in scientific publi- cations. As a result, direct and indirect costs will no longer be projected to the current year, and estimates of indirect morbid- ity costs have been discontinued. For more information, visit nhlbi.nih.gov/about/factpdf.htm. Lack of health insurance and other barriers prevent many Americans from receiving optimal health care. According to the US Census Bureau, approximately 48.6 million Americans (15.7%) were uninsured in 2011, including one in three Hispanics and one in 10 children (18 years of age and younger). Uninsured patients and those from ethnic minorities are substantially more likely to be diagnosed with cancer at a later stage, when treatment can be more extensive and more costly. The Afford- able Care Act is expected to substantially reduce the number of people who are uninsured and improve the health care system for cancer patients. For more information on the relationship between health insurance and cancer, see Cancer Facts & Fig- ures 2008, Special Section, available online at cancer.org/ statistics.

Major Cancer Types Leukemia and lymphoma Leukemia is a cancer of blood-forming cells arising in the bone marrow. Lymphomas are cancers of a certain type of white blood cell (lymphocyte) that can arise anywhere lymphocytes can be found, including bone marrow, lymph nodes, the spleen, the intestines, and other areas of the lymphatic system. Leukemias and lymphomas are classified according to the type of cell that is exhibiting uncontrolled growth. The two most common types of leukemia in children and ado- lescents are acute lymphocytic leukemia (ALL) and acute myeloid leukemia (AML). Chronic leukemias are very rare in children and adolescents. ALL accounts for about 80% of leuke- mia cases in children and 56% of leukemia cases in adolescents. Acute myeloid leukemia (AML) is less common in children than ALL, comprising about 15% of leukemia cases in children and 31% in adolescents.

Common side effects of cancer treatment

• Low red blood cell counts (anemia) can result in pallor, dizziness, weakness, lack of energy, headache, and irritability. Low platelet counts (thrombocytopenia) can result in easy bleeding and bruising. Low white blood cell counts (including low neutrophil counts or neutropenia) reduce the body’s ability to fight infection. Low blood cell counts can be treated by transfusions or hematopoietic growth factors, and risk of infection may be reduced by prophylactic antibiotics.
• Gastrointestinal side effects are common among children receiving chemotherapy or radiation therapy, and can include oral mucositis (irritation and/or sores in the mouth), diarrhea or constipation, nausea, vomiting, and retching. Gastrointestinal side effects can result in poor nutritional intake, leading to weight loss and delayed growth. Medications, such as antiemetics given before chemotherapy, are available to reduce some of these side effects, and nutritional advice is available to help children and parents with these issues. Nutritional support, such as tube feedings, intravenous feedings, or appetite stimulants, may be recommended.
• Pain may arise from the tumor as it presses on bone, nerves, or body organs; it can also result from procedures, including surgeries and needle sticks. Pain can also be a side effect of some cancer treatment, such as neuropathic pain from some chemotherapy drugs. Pain is often treatable by medication and other integrative non-medicine therapies. Children whose pain cannot be well-controlled by available interventions should be seen by a specialist in pediatric pain management.

Research on cancer

The American Cancer Society, through its Extramural Grants program, funds individual investigators engaged in cancer research or training at medical schools, universities, research institutes, and hospitals throughout the US. As of September 2013, this program is funding approximately $29 million in research specifically related to childhood and adolescent cancer through 56 research grants. Additionally, the Society is funding about $16 million in brain cancer research, $28 million in leuke- mia research, and $15 million in lymphoma research covering both childhood and adult disease. Following are some examples of ongoing Society-funded child- hood and adolescent cancer research projects:
•  Researchers at the University of Texas, Southwestern Medi- cal Center are focused on what causes rhabdomyosarcoma. They have discovered that many cases are associated with a fusion of two genes. The team is currently conducting studies to understand the consequences of this gene fusion, with the goal of creating new therapies for this difficult-to-treat cancer.
•  Investigators from the University of Kansas Medical Center are attempting to better understand metastasis in osteosarcoma. The investigators have discovered that a particular regulatory protein, MTBP, can interfere with the primary growth of osteosarcoma and its ability to metastasize to distant sites. A better understanding of the molecular events that promote metastases will provide the framework for improved prevention and treatment.
•  A research team at the Children’s Hospital of Los Angeles is focused on trying to improve treatment of medulloblastoma. Recent studies have shown that radiation treatment, when added to surgery and chemotherapy, may not be necessary for some children. The researchers are trying to develop a prog- nostic tool that would identify those children who might be cured without use of radiation to spare them the additional side effects associated with radiation.
•  Researchers at Yale University are comparing two survivor- ship models for children with cancer to improve long-term outcomes and quality of life in these patients. Specifically, the researchers are comparing the effectiveness of “survivor- ship clinics” to care provided by primary care physicians with training in survivorship care.

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