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Diseases » Cancer » Introduction


Cancer: Introduction

Cancer is a general term for a group of diseases that occur when there is an uncontrolled growth of abnormal cells in one or more organs or tissues of the body.

Cancer is one of the leading causes of death globally. The top cancer killers include lung cancer, colorectal cancer, breast cancer, prostate cancer, and pancreatic cancer. The most common types of cancer include prostate cancer, breast cancer, lung cancer, colorectal cancer, and bladder cancer.

Normally, the body's cells that are old or damaged will stop dividing and die before they can become cancerous. These cells replaced by healthy young cells. Cancer occurs when a genetic mutation causes old or damaged cells to continue to divide and multiply uncontrollably. This results in the development of a malignant tumor or other abnormalities that interfere with the functioning of the affected organ or tissue. Left untreated, cancerous cells can continue to multiply and spread to other parts of the body and interfere with more of the body's vital processes.

There are two main types of cancer. Primary cancer is the first type of cancer that develops. Secondary cancer is caused by a cancer that has begun in another part of the body and spreads to another site, such as primary lung cancer or breast cancer that spreads to the brain, causing secondary brain cancer.

Secondary cancer is also called metastatic cancer. Cancer can metastasize by growing directly into nearby tissues and organs or by spreading through the circulatory system or lymphatic system to other areas of the body.

The cause of cancer differs depending on the specific type of cancer. In general, cancer is caused by inherited genes that increase susceptibility to cancer and/or by environmental factors. Environmental factors include exposure to certain chemicals, such as chemicals found in pollution, smoking, and tobacco. Other environmental factors include specific viruses and bacteria, such as HPV, and/or exposure to excessive radiation, such as from the sun.

Risk factors for cancer vary depending on the specific type of cancer, but common risk factors include smoking, obesity, excessive alcohol consumption, engaging in unsafe sexual practices, having a family history of cancer and excessive exposure to the sun.

Symptoms and complications of cancer vary greatly between different types of cancer. For more details on key symptoms and complications, refer to symptoms of cancer.

Diagnosing cancer begins with taking a thorough personal and family medical history, including symptoms and risk factors for cancer. The diagnostic process also includes completing a thorough physical exam.

Diagnostic testing varies depending on the suspected type of cancer. Testing can include a combination of imaging tests, such as MRI, PET scan and/or CT scan, which use computer technology to create detailed pictures of the body. An angiogram may also be done to illuminate blood vessels that feed blood to a tumor.

Diagnostic testing generally also includes a biopsy. In a biopsy a sample of cells or tissues are taken from the tumor and examined under a microscope for the presence of cancer cells or abnormal changes in tissue that can lead to cancer. This will determine if a tumor is cancerous or benign.

A diagnosis of cancer can be missed or delayed because some symptoms of cancer are similar to symptoms of other conditions. For more information about other diseases, disorders and conditions that can mimic cancer, refer to misdiagnosis of cancer.

Cancer is most treatable and curable if it is caught in the earliest stages of the disease. The prognosis for people with cancer varies depending on the location and stage of advancement of the cancer, age of the patient, general health status, and other factors. For details about treatments, refer to treatment of cancer. ...more »

Cancer: Cancer is caused by an abnormal overgrowth of cells with more than 100 cancer subtypes depending on which cell grows. In many cancers, the cells clump together to form solid tumors, but in some the cells are dispersed around the blood stream (leukemia) or the lymphatic system (lymphoma).

Prognosis of cancer has improved greatly in modern times owing to treatment advances and early detection programs. However, although survival rates have improved, cancer still remains the 2nd top cause of death, second only to heart disese in the USA.

Misdiagnosis of cancer is naturally possible but not common if professional medical advice is sought, because physicians will usually perform comprehensive diagnostic testing if cancer is a possibility. Diagnostic tests have also improved in accuracy including newer tumor marker blood tests. Self-diagnosis of cancer is usually incorrect and quite common is for people to fear that they have cancer based on a symptom (e.g. weight loss, persistent cough, lumps, or frequent urination), only to find out they have other less severe conditions. On the other hand, sadly common is for people to have cancer but be unaware of it, because many types have a slow insidious onset without early symptoms. For this reason, regular screening for particular types of cancer is valuable in preventing severe cancer cases. ...more »

Cancer: Symptoms

The symptoms of cancer differ depending on the specific type of cancer. Symptoms also vary among individuals and are different depending on the stage of advancement of cancer, where it is located, and what types of organs and tissues are affected. There are often no symptoms in very early cancer.

Symptoms of cancer are generally due to the impact of increasing numbers of abnormal ...more symptoms »

Cancer: Treatments

The general goal of treatment of cancer is to bring about a complete remission of the disease, in which there is no longer any sign of the cancer in the body. The prognosis for people with cancer varies greatly depending on the specific type of cancer, location and stage of advancement of the cancer, age of the patient, general health status, and other factors. ...more treatments »

Cancer: Misdiagnosis

A diagnosis of cancer can be delayed or missed because in early stages there may not be any symptoms. In addition, some symptoms of cancer can be vague and similar to symptoms of other diseases or conditions. For example, symptoms of brain cancer may mimic symptoms of a migraine headache or transient ischemic attack. Symptoms of breast cancer may resemble symptoms of mastitis or ...more misdiagnosis »

Symptoms of Cancer

Treatments for Cancer

Home Diagnostic Testing

Home medical testing related to Cancer:

Wrongly Diagnosed with Cancer?

Cancer: Related Patient Stories

Cancer: Deaths

Read more about Deaths and Cancer.

Alternative Treatments for Cancer

Alternative treatments or home remedies that have been listed in various sources as possibly beneficial for Cancer may include:

Types of Cancer

  • Cancer type by severity:
    • Benign tumor - non-cancerous tumors.
    • Malignant tumor - cancerous tumors.
    • Metastatic cancer - spreading of cancer beyond its initial site to lymph nodes and/or other body areas.
  • Cancer type by type of tumor:
  • more types...»

Diagnostic Tests for Cancer

Test for Cancer in your own home

Click for Tests

Cancer: Complications

Review possible medical complications related to Cancer:

Causes of Cancer

Read more about causes of Cancer.

More information about causes of Cancer:

Disease Topics Related To Cancer

Research the causes of these diseases that are similar to, or related to, Cancer:

Cancer: Undiagnosed Conditions

Commonly undiagnosed diseases in related medical categories:

Misdiagnosis and Cancer

Spitz nevi misdiagnosed as dangerous melanoma skin cancer: One possible misdiagnosis to consider in lieu of melanoma is spitz nevi. See melanoma and more »

Cancer: Research Doctors & Specialists

Research related physicians and medical specialists:

Other doctor, physician and specialist research services:

Hospitals & Clinics: Cancer

Research quality ratings and patient safety measures for medical facilities in specialties related to Cancer:

Choosing the Best Hospital: More general information, not necessarily in relation to Cancer, on hospital performance and surgical care quality:

Cancer: Rare Types

Prognosis for Cancer

Research about Cancer

Visit our research pages for current research about Cancer treatments.

Clinical Trials for Cancer

The US based website lists information on both federally and privately supported clinical trials using human volunteers.

Some of the clinical trials listed on for Cancer include:

Prevention of Cancer

Prevention information for Cancer has been compiled from various data sources and may be inaccurate or incomplete. None of these methods guarantee prevention of Cancer.

  • Prevention depends on the specific type of cancer but some methods are common
  • Avoid sunlight exposure - to prevent skin cancer and melanoma.
  • Eat a healthy diet
  • Regular checkups at the doctor
  • Regular screening for common cancers - early detection of any abnormality can lead to prevention of severe cancers and easier treatment.
  • more preventions...»

Statistics for Cancer

Cancer: Broader Related Topics

Cancer Message Boards

Related forums and medical stories:

Article Excerpts about Cancer

Cancer is a group of more than 100 different diseases. Cancer occurs when cells become abnormal and keep dividing and forming more cells without order or control. All organs of the body are made up of cells. Normally, cells divide to produce more cells only when the body needs them. If cells divide when new ones are not needed, they form a mass of excess tissue called a tumor. Tumors can be benign (not cancer) or malignant (cancer). The cells in malignant tumors can invade and damage nearby tissues and organs. Cancer cells can also break away from a malignant tumor and travel through the bloodstream or the lymphatic system to form new tumors in other parts of the body. The spread of cancer is called metastasis. (Source: excerpt from Cancer: NWHIC)

Definitions of Cancer:

A tumor composed of atypical neoplastic, often pleomorphic cells that invade other tissues. Malignant neoplasms usually metastasize to distant anatomic sites and may recur after excision. The most common malignant neoplasms are carcinomas (adenocarcinomas or squamous cell carcinomas), Hodgkin's and non-Hodgkin's lymphomas, leukemias, melanomas, and sarcomas. -- 2004 - (Source - Diseases Database)

Any malignant growth or tumor caused by abnormal and uncontrolled cell division; it may spread to other parts of the body through the lymphatic system or the blood stream - (Source - WordNet 2.1)


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