Australian scientists have discovered a mechanism that causes lung cancer cells to re-grow even after chemotherapy. Scientists hope this discovery can help them find new ways of battling lung cancer.

The study, led by Professor Neil Watkins of the Monash Institute of Medical Research focused on blocking the mechanism that allows cancer cells to re-grow.

"Some aggressive types of cancer respond very well to chemotherapy, but then the real challenge is to stop the tumor coming back. That's what we investigated," Watkins said.

Small cell lung cancer or SCLC is an extremely aggressive type of lung cancer. SCLC is usually treated with chemotherapy but the cancer cells can re-grow and is less responsive to the chemo the second time around.

The team of international researchers found that a drug can stop the SCLC cells from re-growing after chemotherapy. The drug targets growth signals in the cells and stops them from multiplying.

The study published in the journal, Nature Medicine shifts the focus away from shrinking the tumor using chemotherapy to preventing the tumor from ever coming back. Researchers can now find new SCLC treatments that block the growth pathway, called "Hedgehog".

"This discovery gives us important clues for designing new treatment approaches. By using drugs to inhibit the Hedgehog signalling, we should be able to increase the effectiveness of chemotherapy and reduce the risk of cancer relapse," said Watkins

The study has already prompted other doctors to change their approach to lung cancer cell research. In the Monash Medical Centre, right next door to MIMR, doctors are already changing the focus of medical trials by using the research to attempt to block the Hedgehog pathway.

"Based on this research, we need to change our approach. We will re-design our clinical trials to test how these new therapies can improve patient outcomes following chemotherapy," said Dr Vinod Ganju, a medical oncologist at the Monash Cancer Centre.

"Our relationship with MIMR means we can make this happen relatively quickly and take immediate advantage of this research breakthrough."