BY MARY BROPHY MARCUS
Cancer researchers used last week's meeting of the American Society of Clinical Oncology as the forum for announcing the results of several new cancer studies. New information from the conference and in recent medical journals shows the unprecedented progress scientists are making toward halting the many forms of the disease:
Camptosar. A relatively new injectable chemotherapy drug may help conquer the second leading cause of cancer deaths in the United States--colorectal cancer. Camptosar, made by Pharmacia & Upjohn of Kalamazoo, Mich., from the Chinese Camptotheca acuminata tree, was approved two years ago by the Food and Drug Administration. Recent clinical trials found it shrank and slowed the growth of tumors in the lower digestive tract. Researchers announced that Camptosar was effective in patients whose colon cancer had spread throughout the body and recurred after standard chemotherapy. In the trials, 36 percent of 279 patients on Camptosar were alive after a year, while only 14 percent of patients who had received usual care survived. Oncologists plan to examine the drug's effectiveness in people with early-stage colon cancer, as well as in cancers of the liver, esophagus, and stomach.
Taxol. The word cure was also batted around at the meeting in Los Angeles during discussions of Taxol, a breast cancer fighter derived from the yew tree. Research showed that when standard chemotherapy and Taxol are administered after surgery in women whose cancer has traveled to their lymph nodes, death rates dropped 26 percent and the chances of the cancer's return were reduced 22 percent, compared with patients who received only standard chemotherapy. Until now, doctors have used Bristol-Myers Squibb's drug primarily to treat advanced breast cancers. Experts hope research in early-stage cancer patients will show Taxol can destroy bad cells before they fan out to the lymph nodes. Of 183,000 women diagnosed with breast cancer each year, it is estimated that as many as 75,500 will be eligible for the new therapy. "Taxol is going to unquestionably save lives," says Larry Norton, head of medical oncology at Memorial Sloan-Kettering Cancer Center, who is among those researching the drug.
Herceptin. About one third of breast cancer patients carry large amounts of a protein called HER2. Standard chemotherapy doesn't work with very ill breast cancer patients with a lot of HER2. But doctors have found that they can extend life for 25 percent of these women using a drug called Herceptin, by Genentech of South San Francisco, Calif. This drug is exciting to oncologists, says Sloan-Kettering's Norton, because when used in combination with Taxol, it appears to double, even triple, Taxol's effectiveness without adding major side effects.
SERMs. Further research was introduced confirming the power of Eli Lilly's raloxifene in reducing the risk of breast cancer. The drug, marketed as Evista, is what is called a selective estrogen receptor modulator, or SERM. Designed to fight osteoporosis by activating special estrogen receptors in bone, raloxifene appears to reduce the risk of breast cancer by more than 50 percent, and by as much as 83 percent in post-menopausal women. Unlike tamoxifene, another SERM made by Zeneca, it's not linked to increases in uterine cancer.
PSA test. Many urologists recommend that men over 50 get an annual PSA (prostate specific antigen) blood test, which measures a protein that rises when prostate cancer is present. Another blood test is now available for men whose PSA results fall between 4 and 10, what doctors consider a gray area. Biopsies are needed to know if cancer exists for sure. The new free PSA test, which measures PSA that floats free or is not bound to proteins, helps doctors rule out cancer in about 25 percent of men in that questionable range. That means about 200,000 fewer men will have to undergo biopsies each year.
Smoking. Away from the conference, a study discussed in an editorial in last week's Journal of the National Cancer Institute threatens to undo years of health education. A study of American and Canadian women with a particular gene that increases the chance of breast cancer found that smoking one pack of cigarettes a day for four or more years appears to reduce the risk of developing breast cancer. This doesn't mean you should smoke, says Paul Kleihues of the International Agency for Research on Cancer, in Lyon, France. That's playing Russian roulette with lung cancer and numerous other diseases. Kleihues and his colleagues believe smoking reduces estrogen production, thus slowing cancer growth. Experts are quick to say more studies are required.