TUESDAY, Aug. 12 (HealthDay News) -- Preliminary research has produced promising findings regarding a possible alternative treatment for people with a common type of lung cancer.

The new combination of chemotherapy drugs could eventually become another option for people with advanced non-small cell lung cancer, which is very difficult to treat, the Japanese researchers suggest.

Even if it works, however, the treatment isn't likely to add many months to the lives of patients. And the study only represents the second in three necessary stages of research.

"We really don't know if it's better than current therapy," said Dr. Norman Edelman, chief medical officer with the American Lung Association. Still, he added, "more study is warranted."

At issue are patients with advanced cases of non-small cell lung cancer, which makes up about 85 percent to 90 percent of lung cancer cases, according to the American Cancer Society.

Treatment with chemotherapy drugs is difficult, because the medications can cause side effects and may not add more than a few months to a patient's life, said lead investigator Dr. Isamu Okamoto, an associate professor in the Department of Medical Oncology at the Kinki University School of Medicine in Osaka.

But new treatments are needed, Okamoto said, even if they don't greatly extend life spans. "The main purpose of chemotherapy for metastatic advanced non-small cell lung cancer is to improve quality of life, since the patient populations are never cured," he said.

The new study looks at 56 patients with advanced lung cancer who were treated with chemotherapy drugs called S-1 and irinotecan.

Chemotherapy drugs are designed to kill cancer cells while causing as little harm as possible to healthy cells. Irinotecan is already in use in the United States; S-1 is approved in Korea and Japan, but not yet in the United States.

The findings are published in the Aug. 15 issue of Clinical Cancer Research.

About 28 percent of patients responded to the treatment. They lived for an average of 15 months and made it an average of 4.9 months without getting worse.

The researchers reported that the patients suffered less severe side effects than would be expected if they'd taken the usual platinum-based chemotherapy.

According to the researchers, studies of the existing platinum treatment suggest that patients who take it live for an average of seven to 14 months.

The next step would be to directly compare the new chemotherapy regimen to the existing platinum treatment by randomly assigning patients to one or the other.

More information

Learn more about non-small cell lung cancer from the American Cancer Society.