They studied 2,337 people who got palliative radiation for advanced cases of the most common type of lung cancer (non-small cell lung cancer). Such advanced cases are typically considered "incurable," with "dismal" odds of survival, the researchers write.
Average survival was less than five months. But there were exceptions.
Twenty-four people -- about one in a hundred -- lived for at least five more years. For 18, cancer didn't worsen during that time. Nearly a third of those who survived for five years lived another five years after that.
The researchers included Michael Mac Manus, MD. He works in Melbourne, Australia, in the radiation oncology department of the Peter MacCallum Cancer Center, where the patients were diagnosed.
Reasons Not Clear
At the time of diagnosis, the survivors had had better function and their cancer was less likely to have spread beyond the lungs.
The findings might explain some cases of survival that get chalked up to unusual treatments or faith healings, the researchers note. They admit they can't explain the findings based on the available data.
Perhaps the survivors' tumors were particularly responsive to radiation or slower to spread, though that's not certain, write Mac Manus and colleagues.
They call for more studies and encourage radiation oncologists to "be aware of the potential for long-term survival" and keep palliative radiation doses to tolerable levels.