The expression profile of 15 key genes may predict aggressiveness of early-stage non-small cell lung cancer and identify the patients most likely to benefit from postoperative chemotherapy, according to a presentation at the annual meeting of the American Society of Clinical Oncology.

"Not all patients benefit from chemotherapy and not all patients require chemotherapy after surgery," said lead author Ming Tsao, MD, professor of laboratory medicine and pathobiology at the University of Toronto. "Knowing that a patient has a genetic signature for a more aggressive cancer and that their chance of cure may be improved with chemotherapy gives patients and their doctors a clearer picture of the need for post-operative treatment."

The current study is a follow-up analysis of data from a trial conducted by the National Cancer Institute of Canada Clinical Trials Group (JBR.10, conducted in collaboration with the US National Cancer Institute), which showed a significant survival benefit from postoperative vinorelbine and cisplatin in patients with stage I and II non-small cell lung cancer.

In the current analysis, Researchers performed a genetic analysis of tumor tissue from the 133 (28 percent) of the 482 patients from the JBR.10 study who had banked frozen tumor samples available. They identified a group of 15 genes that together predicted patient outcome. Some of these genes are known to play important roles in cell growth and death or regulate other genes involved in cancer.

The investigators first identified the 15-gene expression profile in 62 patients who did not receive adjuvant chemotherapy and used it to predict which patients had aggressive cancers with a high risk of recurrence and death (31 patients) and which had less aggressive disease and a low risk of recurrence (31 patients).

Finally, researchers checked the gene profile in 71 patients who were randomized to chemotherapy in the JBR.10 trial. Patients predicted to have aggressive disease were found to obtain the greatest benefit from chemotherapy -a 67 percent reduction in the risk of death - while chemotherapy did not reduce the risk of death in patients designated as low risk.

While a previous JBR.10 analysis showed that overall, only patients with stage II disease benefited from chemotherapy after surgery, this study has demonstrated that the 15-gene signature may identify patients with both stage I and II cancers who may benefit from post-operative chemotherapy, further supporting its use in the selection of appropriate treatment.