[MOL] Cancer Treatments [01070] Medicine On Line


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[MOL] Cancer Treatments



Checklist of CANCER TREATMENTS

For years doctors and cancer patients had only three options: surgery, radiation and chemotherapy. But that's starting to change, as a new generation of more sophisticated treatments moves out of the lab

TIME Chart By LAWRENCE MONDI, J. MADELEINE NASH and ALICE PARK


TREATMENT TARGET HOW THEY WORK STATUS
Anti- angiogenesis Factors Multiple A growing tumor requires plenty of nutrients, and to make sure it gets them the tumor secretes substances that stimulate the growth of new blood vessels. A number of agents can block this process--at least in animals. See chart below
Anti- metastatic Factors Multiple What kills most cancer patients is not the primary tumor but its metastatic spread. Scientists have identified a class of enzymes that enables cancer cells to enter the bloodstream by dissolving tissue and boring holes through capillary walls. New drugs could keep cancer cells confined to one spot. Human tests have just begun
Anti- oncogenic Factors Multiple, including breast, colon, pancreatic and lung Tumors do more than pick up growth factors that circulate in the bloodstream; they also make them by switching on "oncogenes." Many cancers, for example, have been found to contain mutations in the ras oncogene, and companies are racing to develop drugs that inhibit its growth-promoting activity. Human tests are in early stages
Chemo- prevention Therapies Breast, head and neck Many breast cancers depend on the female hormone estrogen to stimulate their growth. Tamoxifen, which acts as an antiestrogen in the breast, has been shown to prevent the development of this form of cancer. Preliminary evidence suggests that a newer compound, raloxifene, may confer a similar benefit without serious side effects. Compounds know as retinoids, derivatives of vitamin A, can prevent recurrence of certain head and neck cancers. Tamoxifen has been approved as a treatment for breast cancer; raloxifene, as a treatment for osteoporosis
Gene Therapies Multiple, including breast, ovarian and small-cell lung cancers In tumors, genes that are supposed to serve as checks on runaway cell growth are often so damaged that they stop functioning. Scientists hope to correct this problem by engineering viruses that can "infect" cancerous cells with healthy tumor-suppressor genes. Preliminary evidence suggests that this approach can sometimes cause tumors to stop growing and even shrink in size. Testing in humans has just begun
Chemo- therapy Multiple New, more selective compounds and powerful but less toxic versions of older drugs are being added to the oncologist's arsenal. Oral and wafer formulations of injectable drugs have made the delivery of chemotherapy more convenient for patients. Enclosing cancer-killing toxins in a protective lipid "envelope" can increase their effectiveness while sparing normal tissues. In the past two years, the FDA has approved two dozen new chemotherapy agents
Monoclonal Antibodies Non-Hodgkin's lymphoma, breast, colon, melanoma Like miniature guided missiles, these biological constructs home in on specific proteins displayed on the surface of cancer cells. By blocking strategic sites, monoclonals can interfere with a tumor's ability to absorb growth factors from the bloodstream. They can also carry radioactive and chemical toxins that directly destroy malignant tissue. Rituxan won FDA approval last year; Bexxar and Herceptin could be on the market within a year
Radiation Therapies Multiple: often prostate and solid tumors in internal organs; lymphomas Radiation destroys cancerous cells but can damage healthy ones as well. Using 3-D computer images and new delivery techniques like radiation "seed" implants, doctors can aim doses with microscopic precision, sparing healthy tissue. In use
Surgical Procedures Multiple Doctors are always looking for ways to make this standard treatment more effective and less traumatic for the patient--for example, by removing part rather than all of a breast or preceding surgery with other treatments. One promising new technique is lymphatic mapping, in which surgeons use dyes and radioactive tracers to help them be more selective in removing nodes. Widely available; the newest procedures are performed at most large cancer centers
Vaccines Melanoma, breast, colon, ovarian, pancreatic and many others Malignant growths have a deadly knack for skirting around the body's immune system. But scientists are finding that by vaccinating patients with antigens derived from tumors, they can sometimes goad white blood cells into attacking cancerous tissues. Dozens of vaccines are being tested





WHO'S WHO IN ANGIOGENESIS
Dr. Folkman's approach is not the only one--or the most advanced
DRUG WHO'S WORKING ON IT HOW IT WORKS SOURCE STATUS
Marimastat British Biotechnology and the NCI; blocks the activity of enzymes Needed to build tumor blood vessels; synthesized in the lab Synthesized in the lab Being tested in breast-cancer patients
SU5416 Sugen and UCLA Prevents a tumor blood-vessel growth factor from binding to its receptor Synthesized in the lab Being tested for safety in patients
Neovastat Aeterna Laboratories Inhibits activity of enzyme involved in the growth of tumor blood-vessel cells Derived from cartilage of spiny-dogfish sharks Safety tested for lung, breast, prostate cancer
Combreta- statin Oxigene Destroys tumor blood-vessel cells Originally derived from African bush willow Human studies to begin this fall
THP-dox University of Texas Southwestern and ILEX Oncology Attaches to blood-vessel cells and delivers toxin to vessels and tumors Synthesized in the lab Still being studied in animals
Angiostatin and endostatin Children's Hospital and EntreMed Somehow blocks the growth of tumor blood vessels Originally derived from mouse urine First human trials expected within a year
Tamoxifen Zeneca will evaluate Mechanism unknown; may block growth of tumor blood vessels Synthesized in the lab New trials to block blood vessels may begin shortly
TNP-470 TAP Pharmaceuticals Blocks enzyme that instructs tumor blood-vessel cells to divide Originally derived from a fungus Being tested in patients


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