Research explores role of timing, aggression in lung cancer
Western-led research has discovered that timing, in combination with aggression, are possible keys to long-term survival for patients with limited metastatic lung cancer.
"We always have the bias that if you do more treatment earlier it's what's best. There have been some high-profile studies recently that have actually shown that not to be the case," said George Rodrigues, a Schulich School of Medicine & Dentistry professor. "I don't think we should have the single mindset that more is better, but at the same time, we want to improve things for our patients."
When cancer remains limited to the lung, almost one-fifth of patients survive. However, once it spreads throughout the body, the chances of survival plummet to less than 2 per cent. Previous research into this metastatic lung cancer, however, suggests certain patients may experience a 'window of opportunity' if their cancer has not spread to more than five sites beyond the lung. This type of cancer is referred to as 'oligometastatic.'
Rodrigues reviewed data from 757 patients with oligometastatic cancer from a dozen centres around the world. Each patient had received aggressive treatment in the lung and all additional metastatic sites.
On average, 30 per cent of patients survived to the five-year mark. However, depending on how aggressive the cancer was, and when it spread beyond the lung, patients fared better or worse. The most positive results showed in patients where the cancer was caught earlier, and did not spread until after the original lung cancer had gone into remission. Nearly half of those patients survived at the five-year mark.
"I wanted to see how well these patients actually do and are there things we can do to predict what's going to happen," Rodrigues said. "What we found was the main predictor is when the metastatic disease comes. If you have the initial cancer, and then some time passes before the metastatic disease comes, that's the best scenario. That tells you, biologically, the cancer is not the same as maybe something that comes right away."
Survival rates decreased the more the cancer spreads while active in the lung. However, even those patients in the highest-risk group saw a dramatically better prognosis with aggressive treatment. Their five-year survival averaged almost 14 per cent.
"This study clearly demonstrates we can identify selected patients with metastatic lung cancer who can have extended survival," said Rodrigues, a clinical scientist at Lawson Health Research Institute. "What is still unknown is whether this favourable survival is due to aggressive treatment, or due to the underlying nature of the cancer itself."
This research was featured at an American Society for Radiation Oncology meeting last month in San Francisco.
Rodrigues is now part of a group leading an international randomized clinical trial to answer this question. He and his team are proposing a new risk classification scheme to guide physicians in treatment decisions and in the design of future clinical studies. This system will be the first ever proposed for oligometastatic disease for any form of cancer.
A randomized study will see two-thirds of patients getting aggressive therapy treatment, with the remainder getting standard of care.
"If we do the study, and the aggressive therapy doesn't lead to better outcomes, then we know it's just biology. That helps us to better define how to treat these patients," Rodrigues said. "If we prove an aggressive stance leads to better survival, and it's because of the treatment as opposed to biology, that would help to intensify treatment for everybody.
"Many doctors and patients want that aggressive treatment. We want to be reasonable about this, but we also have to have some evidence. … It's not just quantity of life, which is very important, but if we're going to give aggressive therapies, with potential quality-of-life disturbances, we need to make sure that's balanced with a survival benefit. We can give a lot of aggressive therapy, but if it doesn't translate to survival benefit, we've given a lot of aggressive therapy with cost, side effects and trouble for the patient."
