Small US study suggests celecoxib may reduce risk of lung cancer in former smokers
US scientists have found preliminary evidence that a drug called celecoxib could help to prevent lung cancer in patients who used to smoke and therefore face an increased risk of the disease, according to research published in the journal Cancer Prevention Research.
Researchers at the University of New Mexico carried out a small phase II clinical trial involving celecoxib, which belongs to a group of drugs known as COX-2 inhibitors.
A total of 137 patients took part in the trial, all of whom were at least 45 years of age and had given up smoking for at least one year.
Half of the participants took 400mg of celecoxib twice a day, while the other half received a placebo (dummy drug).
The researchers performed bronchoscopies - where a flexible tube is inserted and used to visualise the inside of the airways and to take cell samples from inside the lungs - at the start of the study, and again six months later in order to determine the patients' lung health.
They did this by measuring the level of a protein called Ki-67, which is raised in growing and dividing cells and can therefore be used as a marker of cell growth. Increased Ki-67 levels have also been used as a marker of early lung cancer development in previous studies.
Analysis revealed that patients who were treated with celecoxib showed a 34 per cent decrease in levels of Ki-67, whereas those who took the placebo typically showed a 3.8 per cent increase.
Patients who had decreases in the Ki-67 index also tended to develop fewer lung nodules, which are sometimes a precursor to cancer.
The findings echo the results of an earlier study published in the same journal in February 2010. However, the researchers emphasised that large phase III trials will be needed to confirm the findings.
Dr Jack Lee, professor of biostatistics at the University of Texas MD Anderson Cancer Centre and statistical editor of Cancer Prevention Research journal, noted that five-year survival for lung cancer is just 15 per cent unless the disease is caught early.
He observed: "The best way [to treat the disease] is to intercept at the earliest stages and try to reverse the processes that can lead to cancer. These studies suggest celecoxib may be a tool to do that."
Professor Jack Cuzick, a Cancer Research UK expert on cancer preventive therapy, said: "Smoking causes one in four cancer deaths in the UK, so it's encouraging to see work which takes us a step closer to effective drugs that could prevent lung cancer in former smokers.
"But we're not there yet - this is a small study that only looked at indirect measurements of lung cancer development, such as increased levels of a protein called Ki-67. So there's a long way to go before recommending that former smokers take celecoxib. Scientists need to run much larger prevention trials that directly measure how the cancer develops if the drug is to reduce the number of people developing lung cancer.
"Nevertheless this is very interesting work which makes a strong case for doing these larger trials. In particular, this result shows that it might be possible to identify a group of patients for whom it is safe to take celecoxib. This is important because the drug is known to increase the risk of cardiac disease, so we'd only want to offer it when the benefits outweigh the risks," he added.