Varieties of cancer:
Carcinomas, the most common types of cancer, arise from the cells that cover external and internal body surfaces. Lung, breast, and colon are the most frequent cancers of this type in the United States.
Sarcomas are cancers arising from cells found in the supporting tissues of the body such as bone, cartilage, fat, connective tissue, and muscle.
Lymphomas are cancers that arise in the lymph nodes and tissues of the body’s immune system.
Leukemias are cancers of the immature blood cells that grow in the bone marrow and tend taccumulate in large numbers in the bloodstream.
Prefixes used in naming cancers
- aden= gland (adenocarcinoma)
- chondr= cartilage (chrondroma)
- erythr= red blood cell (erythroblastoma)
- hemangi= blood vessels (hemangiosarcoma)
- hepat= liver (hepatocarcinoma)
- lip= fat (lipoma)
- lymph/or a/ = lymphocyte (lymphoblastoma, lymphangioma)
- melan= pigment cell (melanocytoma)
- myel= bone marrow (myelosarcoma)
- my= muscle (myocytoma)
- oste= bone (osteoma, osteosarcoma)
Loss of Normal Growth Control
Cancer arises from a loss of normal growth control. In normal tissues, the rates of new cell growth and old cell death are kept in balance. In cancer, this balance is disrupted. This disruption can result from uncontrolled cell growth or loss of a cell’s ability tunderg”apoptosis.” Apoptosis, or “cell suicide,” is the mechanism by which old or damaged cells normally self-destruct.
Cancers are capable of spreading through the body by twmechanisms: invasion and metastasis. Invasion refers tthe direct migration and penetration by cancer cells intneighboring tissues. Metastasis refers tthe ability of cancer cells tpenetrate intlymphatic and blood vessels, circulate through the bloodstream, and then invade normal tissues elsewhere in the body.
Depending on whether or not they can spread by invasion and metastasis, tumors are classified as being either benign or malignant. Benign tumors are tumors that cannot spread by invasion or metastasis; hence, they only grow locally. Malignant tumors are tumors that are capable of spreading by invasion and metastasis. By definition, the term “cancer” applies only tmalignant tumors.
Tdiagnose the presence of cancer, a doctor must look at a sample of the affected tissue under the microscope. Hence, when preliminary symptoms, Pap test, mammogram, PSA test, or fecal occult blood test indicate the possible existence of cancer, a doctor must then perform a biopsy, which is the surgical removal of a small piece of tissue for microscopic examination. (For leukemia, a small blood sample serves the same purpose.) Microscopic examination will tell the doctor whether a tumor is actually present and, if so, whether it is malignant (i.e., cancer) or benign.
Hyperplasia: Instead of finding a benign or malignant tumor, microscopic examination of a biopsy specimen will sometimes detect a condition called “hyperplasia.” Hyperplasia refers ttissue growth based on an excessive rate of cell division, leading ta larger than usual number of cells. Nonetheless, cell structure and the orderly arrangement of cells within the tissue remain normal, and the process of hyperplasia is potentially reversible. Hyperplasia can be a normal tissue response tan irritating stimulus. For example, a callus that may form on your hand when you first learn tswing a tennis racket or a golf club is produced by hyperplasia.
Dysplasia: In addition thyperplasia, microscopic examination of a biopsy specimen can detect another type of noncancerous condition called “dysplasia.” Dysplasia is an abnormal type of excessive cell proliferation characterized by loss of normal tissue arrangement and cell structure. Often such cells revert back tnormal behavior, but occasionally, they gradually become malignant.
Carcinoma in Situ: The most severe cases of dysplasia are sometimes referred tas “carcinoma in situ.” In Latin, the term “in situ” means “in place,” scarcinoma in situ refers tan uncontrolled growth of cells that remains in the original location. However, carcinoma in situ may develop intan invasive, metastatic malignancy and, therefore, is usually removed surgically, if possible.
Tumor Grading: Microscopic examination alsprovides information regarding the likely behavior of a tumor and its responsiveness ttreatment. Cancers with highly abnormal cell appearance and large numbers of dividing cells tend tgrow more quickly, spread tother organs more frequently, and be less responsive ttherapy than cancers whose cells have a more normal appearance. Based on these differences in microscopic appearance, doctors assign a numerical “grade” tmost cancers. In this grading system, a low number grade (grade I or II) refers tcancers with fewer cell abnormalities than those with higher numbers (grade III, IV).
Tumor Staging: After cancer has been diagnosed, doctors ask the following three questions tdetermine how far the disease has progressed:
- 1. How large is the tumor, and how far has it invaded intsurrounding tissues?
- 2. Have cancer cells spread tregional lymph nodes?
- 3. Has the cancer spread (metastasized) tother regions of the body?
Based on the answers tthese questions, the cancer is assigned a “stage.” A patient’s chances for survival are better when cancer is detected at a lower stage number (roman numerals are used for the stages, 1, 2, 3), and Arabic for grades.
- Stage and grade – dnot capitalize either one if it does not begin a sentence.
- Use Roman numerals for cancer stages.
- Use Arabic numerals for cancer grades.
- For clarity, use capital letters or Arabic suffices without spaces or hyphens.
Here are some examples:
- stage 0
- stage I stage IA
- stage II
- stage III stage IIIA stage IIIB
- stage IV
- grade 1
- grade 2
- grade 3
- grade 4
BREAST CANCER – NEW HOPE
Herceptin was initially approved by the Food and Drug Administration in 1998 for use in HER2-positive women with metastatic breast cancer (meaning the cancer has spread beyond the breast tother parts of the body). Later trials revealed a 24 percent increase in median overall survival for women with HER2-positive metastatic breast cancer whwere treated initially with Herceptin and chemotherapy rather than with chemotherapy alone. Studies have alsshown that the drug may cause cardiac problems, but only in a small percentage of patients.
Earlier this year, HER2-positive breast cancer patients got even more good news. In May, the interim results of an analysis of 3,300 patients in twmajor trials that compared the use of Herceptin with chemotherapy tchemotherapy alone were released at the annual meeting of the American Society of Clinical Oncology. “You could have heard a pin drop when they released the results,” remembers Pellegrino, the Montefiore oncologist, whattended the conference.
The results of the analysis, which were alspublished last week in The New England Journal of Medicine, showed that women with early stage HER2-positive breast cancer whreceived Herceptin in combination with chemotherapy cut their risk for breast cancer recurrence by 52 percent, and their risk of death by 33 percent, when compared with women whjust received the chemotherapy. After four years, only 15 percent of women whhad been treated with Herceptin plus chemotherapy experienced a recurrence of the cancer, compared tone third of the women who?d just had chemotherapy. “We found something that is directly affecting people’s lives, bringing them hope,” says Dr. Edith A. Perez, an oncologist at the MayClinic in Jacksonville, Fla., whchaired one of the twtrials (known as the North Central Cancer Treatment Group. “We are curing women here.”
DISCLAIMER: The information provided here is for general informational purposes only, and is provided as a supplement for students enrolled in Meditec’s medical career training courses. The information should NOT be used for actual diagnostic or treatment purposes or in lieu of diagnosis or treatment by a licensed physician.