Researchers attending an annual cancer conference say they're making inroads against lung cancer, the deadliest form of cancer in the US.

The results of 3 studies presented at the American Society of Clinical Oncology meeting showed promising results for treating this disease, which kills more than 160,000 American men and women each year. One study identified a drug that can help people with advanced lung cancer live longer, while the other two suggest a more effective way to treat early stage lung cancer.

"These studies provide important new information that will change the practice of lung cancer … therapy," said Bruce E. Johnson, MD, of the Dana-Farber Caner Institute and Harvard Medical School.

The first study, conducted by researchers at National Cancer Institute of Canada Clinical Trials Group, examined the effects of a new drug called Tarceva (erlotinib) in 731 patients with advanced non-small cell lung cancer, the most common form of lung cancer. The patients had already been treated with chemotherapy, but their cancer was no longer responding.

The patients given Tarceva lived an average of 2 months longer than the patients given a placebo. Because patients with advanced disease generally only survive a few months, an extension of 2 months is significant.

It also took longer for the cancer to progress in the patients taking Tarceva. Symptoms like coughing, pain, and difficulty breathing were held at bay longer in patients who took Tarceva. Side effects of the drug included rash and diarrhea.

"This is a new, well-tolerated oral treatment for patients who previously had very few options," lead study author Frances A. Sheppard, MD, of Toronto's Princess Margaret Hospital, said in a statement. "Patients treated with [Tarceva] in our trial not only lived longer, but they also had better quality of life."

Tarceva is a new type of drug called an EGFR (epidermal growth factor receptor) inhibitor. It works by blocking a signaling pathway that tumor cells need to grow. The lung cancer drug Iressa works by a similar mechanism, but Iressa has not yet been shown to help patients live longer.

Tarceva's manufacturers, Roche, Genentech, and OSI Pharmaceuticals, plan to submit the drug to the Food and Drug Administration for approval this summer. The drug is also being tested against other cancers.

Two other studies presented at the conference found that patients with early stage lung cancer lived longer if they received chemotherapy after curative surgery that removed all the visible cancer. The findings are intriguing because many previous studies of chemotherapy after lung cancer surgery have not shown any benefit from the drugs.

"I'm hopeful that our study will convincingly demonstrate that adjuvant chemotherapy is truly effective in early lung cancer," said Gary M. Strauss, MD, MPH, of Brown Medical School and Rhode Island Hospital, lead researcher on one of the studies. Adjuvant chemotherapy is given after curative surgery to kill any cancer cells that may have spread elsewhere.

Strauss and his colleagues studied 344 people who had undergone surgery for non-small cell lung cancer that was larger than 3 centimeters but had not spread to the lymph nodes or other areas of the body (stage IB). Half the patients were given chemotherapy with paclitaxel (Taxol) and carboplatin, while the rest had no additional therapy. This drug combination is often given to people with advanced lung cancer, but is not usually used in early stage disease.

After 4 years, 71% of the patients in the chemotherapy group were still alive, compared to just 51% of the patients in the other group. About half the patients who received chemotherapy experienced a decrease in infection-fighting white blood cells, a condition called neutropenia, but overall the therapy was well-tolerated, the researchers said. None of the patients who received carboplatin and Taxol died from the treatment.

That could be an important finding, said Strauss.

"The positive results using a carboplatin combination are of particular interest, since many oncologists see carboplatin-based therapy as better tolerated than cisplatin-based regimens in non-small cell lung cancer patients," he said.

Indeed, a study published earlier this year found that chemotherapy with cisplatin also helped patients live longer after lung cancer surgery. But the researchers in that case warned that cisplatin is highly toxic -- it can cause kidney failure and even death, in addition to less severe side effects -- and might not be appropriate for all patients.

Still, cisplatin could be a viable treatment option for some patients. Another study presented at the conference showed that chemotherapy with cisplatin and vinorelbine also improved survival compared to surgery alone.

In that trial, which involved 482 patients with non-small cell lung cancer (stage IB and II – larger than 3 centimeters or spread to nearby lymph nodes), patients who received chemotherapy survived about 94 months, compared to 73 months for patients who had no additional treatment. It also took longer for the cancer to recur in people who took chemotherapy. Two people died from the toxic effects of the drugs.

The research was conducted by doctors at the National Cancer Institute of Canada Clinical Trials Group.

The latest findings could have an impact on treatment practices for early stage lung cancer, researchers involved in both studies said.

"This study should solidify opinion in favor of changing the standard of care for these patients," said Timothy Winton, MD, lead researcher of the Canadian study.