The seven danger signs and symptoms of cancer are as follows:

• Unusual bleeding or discharge.
• A lump or thickening in the breast or otherwise
• A sore that does not heal
• Change in bowel or bladder habits.
• Persistent hoarseness or cough.
• Persistent indigestion or difficulty in swallowing
• Change in a wart or mole.

The causation of cancer is considered multifactorial and results from the interplay between the genetic factors, environmental and behavioral factors. The various major risk factors for cancer are:

• Tobacco - involved in cancers of lung, mouth, larynx, esophagus, pancreas, stomach, colon, cervix, kidney, and bladder. Smoking may lead to an elevated risk of liver and prostate cancer, as well as leukemia. Secondhand smoke causes lung cancer in nonsmokers. Smokeless tobacco causes oral cancer. PAH, N-nitrosamines, aromatic amines, 1,3-butadiene, benzene, aldehydes, and ethylene oxide are carcinogens present in tobacco smoke.
• Obesity and lack of Physical activity-Sedentary lifestyle with lack of physical activity and resultant obesity increase the risk of cancer of colon, breast, endometrium, esophagus, renal cell carcinoma, pancreas, gall bladder etc. Even 30min of activity per day significantly reduces the risk.
• Chronic inflammatory conditions -Include conditions like lichen scleroses, reflux esophagitis, asbestosis, chronic pancreatitis, inflammatory bowel diseases like ulcerative colitis, liver cirrhosis etc.
• Chemical factors -Lung (tobacco smoke, arsenic, asbestos, coal tar etc.), Pleura (asbestos), Oral cavity and esophagus(tobacco smoke, alcohol), Stomach(smoked, salted and pickled foods), bladder(tobacco smoke, benzidine)
• Dietary factors- Alcohol is the best established dietary risk factor for cancer. It increases the risk of cancers including those of the liver, esophagus, pharynx, oral cavity, larynx, breast, and colorectum in a dose-dependent fashion. Dietary fat is associated with cancer of breast, colon, prostate and endometrium. Intake of food and vegetables in higher amounts reduces the risk of cancer.

Cancer to a large extent is avoidable. Many cancers can be prevented.

• Protect your skin from sunlight
• Stay away from tobacco and alcohol
• Get to and stay at a healthy weight
• Get moving with regular physical activity
• Eat healthy with plenty of fruits and vegetables
• Know yourself, your family history, and your risks
• Have regular checkups and cancer screening tests
• Get vaccinated

While cancer is not a single disease entity all forms of cancer share the common feature of growth dysregulation where the cells grow and multiply without restraint. Thus cancers can arise from all sites of the body and the number of cancers is equal to the number of types of cells and tissues we have in our body. It is estimated that there are 200 different types of cells the human body - all of which can potentially grow into a cancer. Further cancers can behave differently even when arising out the same type of cells in the same area of the body depending on their biological characteristics. For example in case of brain tumors low grade and high grade gliomas are considered to originate from the same cell type in the same area but have dramatically different prognosis. Recent research also indicates that cancers may be different depending the different molecular pathways that are deranged in them allowing far greater variability than originially anticipated. However for the purposes of easier treatment selection and classification cancers are broadly classified into the following categories depending upon the type of tissue of origin.

• Carcinomas:These are the commonest types of cancers that arise from lining layers of cells (also known at the epithelium) covering the body and the organs. Epithelial cells have a natural tendency to grow and shed as they cover and protect the various organs, which in turn accounts for their propensity for developing into a cancer. Examples of common carcinomas include skin cancer, head neck cancers, lung cancers, breast cancers, prostate cancer, rectal cancer. Noteworthy is the fact that tobacco and alcohol use have a strong association with the development of nearly all types of carcinomas. As carcinomas arise in the cells lining the organs they are often detectable more easily and therefore several screening methods can be employed for early detection and diagnosis. For example Pap smears enable screening for cervical carcinomas and colonoscopies are effective in the screening for colo-rectal carcinomas. Carcinomas are typically categorized further according the site of origin for example the oral cavity, cervix, colon, rectum etc.
• Sarcomas: These are cancers which arise from the supporting connective tissue, muscles, fat, bones in the body. Unlike the carcinomas these are typically more slow growing tumors and situated outside an organ. However since all organs in the body have a layer of connective tissue that supports the epithelial cells sarcomas can be found in all organs in the body. Further there are various forms of sarcomas with different growth potential that can arise from the same organs. However most of the sarcomas are slow growing tumors that require surgery as a part of the treatment. Unlike carcinomas smoking and alcohol abuse have not been shown to have a strong association with most of the sarcomas. Sarcomas are typically classified on the cell of origin rather than the site of origin.
• Lymphomas/Leukemias: Unlike the other types of cancers mentioned above leukemias and lymphomas are cancers arising from the cells circulating in the blood stream. Leukemias are typically considered as "liquid tumors" as there is no single mass of cancer anywhere in the body but instead the malignant cells cirulate throughout the body. Leukemias are typically seen in young children and have become the model for curable cancers recently through the use of intense chemotherapy schedules along with the judicious use of radiation therapy. While lymphomas also arise from the blood forming cells they usually present with localized masses or tumors that can be seen. Like leukemias these are sensitive to radiation and chemotherapy both of which are important parts of the curative treatment. Recently molecular targetted agents have been used along with the traditional treatment for increasing the cure rates and survival. Lymphomas are classified as per the cell of origin unlike the carcinomas. Recently molecular diagnostic methods have been employed to classify these on the basis of the genetic mutations underlying the development of the cancer.

While the above classification has the merit that it neatly categorizes malignancies into 3 categories with distinct approaches to management exceptions are known to occur. The art and science of treating cancer relies in the timely recognition of these atypical senarios and instituting the appropriate management. As a rule of the thumb surgery along with radiation therapy are the mainstay for the treatment of carcinomas and sarcomas while chemotherapy and radiation therapy play the major role in the treatment of leukemias/lymphomas.

The main specialties involved in the treatment of cancer are:

• Surgical Oncology (with Anesthesiology team)
• Radiation Oncology
• Medical Oncology and Hematology (Including Immunology)
• Pain and Palliative Medicine
• Oncopathology
• Imageology and Interventional Radiology
• Physical and Rehabilitative Medicine (including speech and swallowing)
• Community Oncology (including Dental Medicine)
• Oncology Nursing etc

Cancer is usually detected by clinical examination and confirmed by various tests done in a Hospital. Visible areas in the body can be examined for any swelling or ulcer. Tests like endoscopy, ultrasound examination or CT scan can detect swelling or ulcer within the body. These tests are advised according to the symptoms of an individual. Biopsy or a needle aspiration from the suspected area usually confirms the disease by identifying the cancer cell.

Cancer is nor a contagious disease. A patient cannot transmit the disease to any other person. But, some cancers are found to occur in families. Cancers like breast cancer, colon cancer some types of thyroid cancer, etc are seen in family members. The risk varies from fist degree relative to second degree relative. Also the risk may be higher if both maternal and paternal family members has cancer.

Radiation therapy removes cancer by a form of X-rays. Thus some of the normal areas also get minimal damage. This can cause burning sensation in mouth, ulcer in mouth, dryness, abdominal cramps, diarrhea, skin discoloration etc. These changes are usually temporary. Chemotherapy uses certain drugs that act on fast dividing cells in the body like the cancer cells. Hence some other fast dividing cells are also damaged as in bone marrow, hair etc. A patient may have tiredness, risk of infection, fever, hair loss etc. These side effects also are temporary.

A patient with an early cancer can be cured completely. The chance of cure decreases as the stage of the disease increases. Patient with advanced cancers have the risk of disease coming back even after completely treating the disease. This chance is high during the initial 2-3 years after completing the treatment. Hence all the cancer patients are followed up closely for the first five years and then yearly. An early detection of a recurrence of cancer can be treated with a better chance of cure.