Understanding Cancer

Understanding Cancer

People likely have wondered about the cause of cancer for centuries. Its name derives from an observation by Hippocrates more than 2,300 years ago that the long, distended veins that radiate out from some breast tumors look like the limbs of a crab. From that observation came the term karkinoma in Greek, and later, cancer in Latin.

What causes cancer?
Cancer is a group of more than hundred diseases that develop across time and involve the uncontrolled division of the body’s cells. Although cancer can develop in virtually any of the body’s tissues, and each type of cancer has its unique features, the basic processes that produce cancer are quite similar in all forms of the disease.

Cancer begins when a cell breaks free from the normal restraints on cell division and begins to follow its own agenda for proliferation. All of the cells produced by division of this first, ancestral cell and its progeny also display inappropriate proliferation. A tumor, or mass of cells, formed of these abnormal cells may remain within the tissue in which it originated (a condition called in situ cancer), or it may begin to invade nearby tissues (a condition called invasive cancer). An invasive tumor is said to be malignant, and cells shed into the blood or lymph from a malignant tumor are likely to establish new tumors (metastases) throughout the body. Tumors threaten an individual’s life when their growth disrupts the tissues and organs needed for survival.

Two categories of genes play major roles in triggering cancer. In their normal forms, these genes control the cell cycle, the sequence of events by which cells enlarge and divide. One category of genes, called proto-oncogenes, encourages cell division. The other category, called tumor suppressor genes, inhibits it. Together, proto-oncogenes and tumor suppressor genes coordinate the regulated growth that normally ensures that each tissue and organ in the body maintains a size and structure that meets the body’s needs.

Thus cancer begins when a cell begins dividing uncontrollably, eventually these cells progress to form a visible mass or tumor. This initial tumor is called the “primary” tumor. Cells from the primary tumor can break off and lodge elsewhere in the body where they then grow into secondary tumors. This process is called “metastasis” and a cancer which has spread to other organs is called “metastatic.” When cancer spreads to another organ, the type of cancer remains the type of the primary tumor.

How many cancer types exist?

There are more than 200 different types of cancers.

How to understand the status of cancer?

Inorder to find out information of a particular type of cancer, we need to understand

  • The Medical Name of the Cancer
  • The Stage of the Cancer
  • Possibly the Grade of the Cancer
  • PossiblyOther Prognostic Factors

 

Medical name of the cancer or cancer type

Cancers are termed as xyz cancer or xyz carcinoma, or xyz adenocarcinoma or, xyz sarcoma. These are actually very broad classes of cancer cell types, rather than particular cancers. Sarcomas are cancers of the connective tissue, cartilage, bone, muscle, and so on. Carcinomas are cancers of epithelial (lining) cells. Adenocarcinoma refers to carcinoma derived from cells of glandular origin.

Stage of the cancer

Cancer staging systems describe how far cancer has spread anatomically and attempt to put patients with similar prognosis and treatment in the same staging group. Since prognosis and treatment of cancer depends quite a bit on the stage, it is indeed very important to know what stage one is in. The concept of stage of cancer is applicable to almost all cancers except for most forms of leukemia. Since leukemias involve all of the blood, they are not anatomically localized like other cancers.

There are four different types of staging:

  • Clinical Staging determines how much cancer there is based on the physical examination, imaging tests, and biopsies of affected areas.
  • Pathologic Staging can only be determined from individual patients who have had surgery to remove a tumor or explore the extent of the cancer. Pathologic staging combines the results of both the clinical staging (physical exam, imaging test) with surgical results.
  • Post-Therapy or Post-Neoadjuvant Therapy Staging determines how much cancer remains after a patient is first treated with systemic (chemotherapy or hormone therapy) and/or radiation therapy prior to their surgery or where no surgery is performed. This can be assessed by clinical staging guidelines and/or pathologic staging guidelines.
  • Restaging is used to determine the extent of the disease if a cancer comes back after treatment. Restaging helps determine the and the best treatment options for cancer that has returned.

Roman Numeral Staging is done from I to IV. In general, stage I cancers are small localized cancers that are usually curable, while stage IV usually represents inoperable or metastatic cancer. Stage II and III cancers are usually locally advanced and/or with involvement of local lymph nodes. Prognosis, diagnosis, treatment and management of each cancer at the same stage can be different.

TNM Staging system is for TNM stands for Tumor, Nodes, and Metastases. Each of these is categorized separately and classified with a number to give the total stage. Thus a T1N1M0 cancer means the patient has a T1 tumor, N1 lymph node involvement, and no distant metastases. Of course the definitions of T, N and M are specific to each cancer.

The earlier cancer is diagnosed and treated, the better the chance of its being cured. Some types of cancer like those of the skin, breast, mouth, testicles, prostate, and rectum can be detected by routine self-exam or other screening measures before the symptoms become serious. Most cases of cancer are detected and diagnosed after a tumor can be felt or when other symptoms develop. In a few cases, cancer is diagnosed incidentally as a result of evaluating or treating other medical conditions.Early detection is often key to surviving any form of cancer. While many people will unfortunately still succumb to the cancers, doctors can have great success in treating the cancers when found early.

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