When cancer develops from the epithelial lining of external or internal organs, it is known as a carcinoma.
In general, patients with a carcinoma have fatigue, tiredness, anemia and weight loss. The weight loss can be quite pronounced and rapid. The specific symptoms of a carcinoma depend on where it is located; for instance, a skin cancer, may present the darkening of skin, itching or minor bleeding. A carcinoma of the pancreas may present with abdominal or back pain, nausea and jaundice.
In general, when a cancer is suspected, the following work up is necessary.
Only a few carcinomas have specific tumor makers  which include:
Other tests depend on where the cancer is located. A CT scan and/or MRI is usually obtained to determine the extent and location of the cancer.
Once a cancer has been biopsied, its grade is determined by the pathologist. All patients who have a cancer are staged according to tumor size location, regional and distant lymph nodes involvement and other areas where the tumor may have spread. No treatment should be started until the staging is confirmed.
The TNM system is a universal method to stage cancers. This staging system is accepted by the American Joint Committee on Cancer and the Union for International Cancer Control (UICC). The TNM system is based on the size and extent of the primary cancer (t), the number of lymph nodes involved (N) and the presence of metastases (M). A number is added to each letter to indicate the extent and size of primary cancer and the extent of spread.
Primary tumor (T)
Regional lymph nodes (N)
Distant metastasis (M)
For example, lung cancer classified as T3 N2 M0 refers to a large tumor that has spread outside the lung to nearby hilar lymph nodes but not to other parts of the body. Colon cancer T2 N0 M0 means that the tumor is located only in the colon and has not spread to the lymph nodes or any other part of the body.
The treatment of a cancer depends on the type, stage and patient status. The classical treatments for cancer include surgical resection, chemotherapy, radiation, hormonal therapy, immunotherapy and use of biological agents. In the last decade, the development of biological agents that targer the immune system rather than cancer cells seems to have had a small impact on disease free survival . There are also plan to use certain vaccines to prevent cancer .
The prognosis depends on the type of cancer, the location as well as the stage and grade of the cancer. Other factors that affect prognosis include age of patient, physical status of the individual and how the cancer cells respond to treatment. The higher the stage, the worse the prognosis. It is important to note that just because patient's have advanced cancer does not mean that they do not require treatment. Many of these patients benefit from palliative care and pain control.
Different types of carcinomas have their own etiological factors. In general, it is estimated that nearly one third of cancers globally are due to potentially modifiable risk factors which include the use of tobacco, alcohol consumption and a diet that is low in vegetables and fruits. One very common cause of skin cancers is sunlight. Solar radiation has been linked to actinic keratosis, squamous cell and basal cell cancers . In addition, being obese and having acquired a sexually transmitted infection (eg. Human papillomavirus (HPV) infection) also appear to be risk factors for cancers (eg. cervical cancer) .
Hence, many countries are now trying to introduce steps to help the public reverse these modifiable risk factors. Vaccination against hepatitis B and HPV is now commonly performed in most countries to prevent liver and cervical cancers . Finally, obesity has been linked to several cancers such as lung, colon, breast, kidney and uterus. it is believed that foods high in glycemic index may promote cancers .
Cancer is the second leading cause of death in many western countries, lagging just behind heart disease. The cancer with the highest mortality is that of the lungs. The most common cancer occurring in men is prostate whereas in women, breast cancer is most common. In children, leukemia appears to be the most common malignancy. Cancer is a major public health problem globally and carries a high burden on society. Even when the patients of cancer survive, there is a high risk of developing recurrence.
The exact molecular mechanism that explains cancer development is not known; however, the most widely held theory is that there are one or more mutations of genes leading to damage to the DNA. The genetic mutations transform normal cells into a cancer cell; which multiply repeatedly and unchecked. The genetic mutations may also include activation of oncogenes and inactivation of tumor suppressor genes. There are some individuals who have a genetic predisposition to cancer due of inheritance of mutated genes. While models of carcinogenesis are simplistic in nature, carcinogenesis in reality is a complex phenomenon which requires a constellation of steps that take place over a long period of time.
The subtypes of carcinoma include the following:
One should discontinue smoking, maintain a healthy weight, eat ample fruits and vegetables, exercise regularly and avoid excess alcohol to prevent most types of cancer . It is vital to encourage patients to avoid weight gain as this is also a significant risk factor for some cancers. Safe sex, avoid sharing needles and use of sunscreens are some preventive measures that can be undertaken to avoid cancers.
The majority of cancers that develop in humans are carcinomas. Carcinoma is any cancer that develops from the outer or inner epithelium of an organ. All organs that have an epithelial lining have the potential to develop a carcinoma; for instance, a squamous cell cancer may occur on the surface of the skin. Besides skin, epithelial lining is present in almost all internal organs and passageways like the respiratory tract, gastrointestinal tract and the urinary tract.
Carcinomas are divided into two major groups; namely, adenocarcinomas, which occur in a gland or an organ; and squamous cell carcinoma, that arise from the squamous epithelial lining.
Adenocarcinomas generally occur in endocrine and mucus secreting organs like the pancreas, colon, prostate, breast, lung, liver, kidney, etc. These cancers often present as thickened white plaque and because of the surrounding soft tissue, they are often very invasive locally. This propensity to invade locally often prevents them from being cured by surgical resection. Similarly squamous cell cancer can occur in many organs besides the skin like the bladder, oral cavity, vagina, and anal canal.
Carcinoma is a form of cancer that derives from epithelial cells. People should be educated that some cancers are preventable. In order to prevent cancer, one must change the lifestyle and eat a healthy diet, exercise regularly, discontinue or avoid smoking and drink alcohol in moderation. The diet should consist of plenty of vegetables and fruits, limited amount of fat, and plenty of fiber. It is important to avoid weight gain because obesity has been linked to cancers of the breast, colon, lung, prostate and kidney. One should try and walk at least 1 hour a day 5-6 times a week. To protect from the sun, one should avoid the midday sun, wear appropriate garments, avoid tanning salons and use sunscreens liberally when going out. It is important to get vaccinated against hepatitis B and human papilloma virus as this has been shown to prevent liver and cervical cancers. Finally, one should avoid risky behavior (like sharing needles that may transmit HIV) and practice safe sex.