Checklist of Cancer Treatments

By TIME chart by Lawrence Mondi, J. Madeleine Nash and Alice Park

TREATMENT Anti-angiogenesis Factors

TARGET Multiple

HOW THEY WORK 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.

STATUS See chart below

[TREATMENT] Anti-metastatic Factors

[TARGET] Multiple

[HOW THEY WORK] 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.

[STATUS] Human tests have just begun

[TREATMENT] Anti-oncogenic Factors

[TARGET] Multiple, including breast, colon, pancreatic and lung

[HOW THEY WORK] 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.

[STATUS] Human tests are in early stages

[TREATMENT] Chemoprevention Therapies

[TARGET] Breast, head and neck

[HOW THEY WORK] 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.

[STATUS] Tamoxifen has been approved as a treatment for breast cancer; raloxifene, as a treatment for osteoporosis

[TREATMENT] Gene Therapies

[TARGET] Multiple, including breast, ovarian and small-cell lung cancers

[HOW THEY WORK] 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.

[STATUS] Testing in humans has just begun

[TREATMENT] Chemotherapy

[TARGET] Multiple

[HOW THEY WORK] 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.

[STATUS] In the past two years, the FDA has approved two dozen new chemotherapy agents

[TREATMENT] Monoclonal Antibodies

[TARGET] Non-Hodgkin's lymphoma, breast, colon, melanoma

[HOW THEY WORK] 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.

[STATUS] Rituxan won FDA approval last year; Bexxar and Herceptin could be on the market within a year

[TREATMENT] Radiation Therapies

[TARGET] Multiple: often prostate and solid tumors in internal organs; lymphomas

[HOW THEY WORK] 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.

[STATUS] In use

[TREATMENT] Surgical Procedures

[TARGET] Multiple

[HOW THEY WORK] 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.

[STATUS] Widely available; the newest procedures are performed at most large cancer centers

[TREATMENT] Vaccines

[TARGET] Melanoma, breast, colon, ovarian, pancreatic and many others

[HOW THEY WORK] 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.

[STATUS] Dozens of vaccines are being tested