Doctors typically cut out lung tumors that have not noticeably spread, but they do not routinely put patients through the rigors of chemotherapy, because there has been no clear evidence it improves their chances.
Experts believe that dogma will change as a result of the data released Saturday. The studies show chemotherapy indeed can make a substantial difference in lung cancer, just as it does in breast and colon cancer.
"This will translate into thousands of lives saved every year," predicted Dr. Bruce Johnson, a lung cancer expert at Boston's Dana-Farber Cancer Institute.
The two studies involved patients with what's called non-small lung cancer. Lung cancer is the world's most common malignancy, and about 80 percent of cases are this type.
The new data were presented at the annual scientific meeting in New Orleans of the American Society of Clinical Oncology. At the same meeting last year, an international study offered the first hint of a small benefit to adding chemo to surgery for this kind of cancer.
Nevertheless, many doctors wondered afterward whether the payoff was big enough to change the way they treat lung cancer. The latest studies, which show an even bigger benefit, should tip the profession toward making chemotherapy a standard part of treatment, experts say.
"This will convince even the most skeptical," predicted Dr. David Johnson of Vanderbilt University.
At the same meeting Saturday, other teams reported encouraging data on two newer, so-called targeted drugs that jam up cancer's internal signaling circuits without producing major side effects. These are OSI Pharmaceuticals' Tarceva and ImClone system's Erbitux, the drug that enmeshed Martha Stewart in an insider trading scandal.
Last year's lung cancer study involved somewhat more advanced cases and showed a 5-percentage point improvement in survival after five years in those getting chemo. The latest studies were carefully confined to the patients with the best chances - those with relatively small tumors and no sign of cancer in lymph nodes beyond the lung - and found a larger benefit, roughly 15 percentage points.
"These are paradigm-shifting studies," said Dr. Frances Shepherd of the National Cancer Institute of Canada.
The government cancer institutes of the United States and Canada and involved different drug regimens financed the two studies, but they had remarkably similar outcomes:
-The U.S. study enrolled 344 patients who were randomly given either surgery alone or surgery plus Taxol and carboplatin. After four years, 71 percent getting chemo were still alive, compared with 59 percent getting only surgery.
-The Canadian-sponsored study involved 482 patients and used the drugs vinorelbine and cisplatin. After five years, 69 percent getting chemo were still alive, compared with 54 percent receiving surgery alone.
After these results, "I would have difficulty not offering chemotherapy to my patients," said Dr. Gary Strauss of Rhode Island Hospital, who headed the U.S. study.
In the United States and Canada alone, about 200,000 new cases of lung cancer are diagnosed annually, and 80 percent are non-small cell. Of these, about 30 percent are the same early stage that can be removed surgically.
Another Canadian cancer institute study showed that Tarceva, which has not yet been approved for routine use, could slightly improve survival in people with advanced non-small lung cancer who do not respond to other treatments. In testing on 731 patients, survival increased by two months. Doctors hope results will be better if the drug is started earlier.
Both Tarceva and Erbitux work by blocking epidermal growth factor, one of the errant stimulants that keeps cancer alive. Erbitux was approved in February for use in colon cancer, and Saturday's study shows remarkable benefit against tumors of the tongue, tonsils and voice box.
Dr. James Bonner of the University of Alabama headed a company-sponsored study of 424 patients with cancer that had not spread beyond the neck. The treatment doubled median survival from 28 months to 54 months.
"Nobody anticipated this degree of positive outcome," said Dr. Robert Mayer of Dana-Farber.
The drug was central to Martha Stewart's conviction by a federal jury in March for lying to investigators about why she sold ImClone stock on Dec. 27, 2001. That was the day before the company received a setback from regulators in its eventually successful quest to market Erbitux.
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