Lung cancer still remains difficult to treat
TORONTO â€” There have been some steps forward in treating lung cancer in the last 20 years, but the disease that took the life of Canadian-born newsman Peter Jennings remains one of the most formidable cancers to defeat, doctors say.
Lung cancer is the most common cancer in North America for both men and women and the leading cause of cancer death: this year, more than 22,000 Canadians will be diagnosed with the disease and an estimated 19,000 will die.
"Although there are some treatments for lung cancer that are better now than they had been in years past, it still is a very difficult disease to treat,'' said Dr. Nevin Murray, an oncologist at the B.C. Cancer Agency.
"And even with the modest advances that we've seen, it's something where if you survive lung cancer you're very lucky indeed.''
In fact, only about 15 per cent of lung cancer patients are alive five years or more past diagnosis, Murray said Monday from Vancouver.
"That does represent an improvement,'' he said. "About 20 years ago, it was about half that.''
When it comes to progress against the dreaded cancer in the last decade or two, Murray cites a somewhat higher proportion of patients being diagnosed at an earlier stage of the disease, which boosts their chances of survival.
As well, today's diagnostic technology helps doctors better assess which patients would benefit from surgery -- so they can provide it as soon as possible. It also avoids putting others through "open and close'' surgeries that end up showing only that a tumour is inoperable.
One of the biggest advances has come in the last year or so with several international studies showing that the use of chemotherapy after surgical tumour removal significantly raises the survival rate in patients whose cancer has not spread.
"So, that's a major shift in our treatment policy,'' said Dr. Frances Shepherd, a lung cancer specialist at Toronto's Princess Margaret Hospital. "Before, patients were just operated on. One hoped for the best, but there was no treatment given.''
Shepherd believes doctors will be able to make a dent in lung cancer deaths in the next five to 10 years, but it would require expanded screening of high-risk patients.
"We still can't cure the majority of lung cancers because they present at a time when they are not operable,'' she said, explaining that in two-thirds of patients, the cancer has spread outside the lung.
"We need to find patients earlier,'' said Shepherd, who is involved in a study to see if CT scanning will pick up cancers when they are relatively tiny (chest X-rays are far less accurate), much as mammograms can detect early-stage breast tumours.
Malignancies the size of a dime, for instance, have about a 95 per cent cure rate, she added.
"We're hoping to find them earlier because by the time you get symptoms -- with a cough or you cough up blood or you have chest pain -- it's usually too late.''
Still, prevention remains the best therapy of all, doctors stress. Simply put, said Shepherd, "Don't smoke.''
When it comes to conquering cancer, Murray said nothing could be more of a breakthrough than the knowledge that curtailing tobacco use could prevent most tumours in the lungs.
At least 85 per cent of lung cancer cases are attributed to tobacco use, says the Lung Association of Canada.
But smoking is also linked to several other malignancies -- bladder, pancreatic and kidney, to name a few.
"There's a whole group of cancers that are associated with tobacco smoking,'' said Murray. "Overall, about 30 per cent of cancer mortality is from smoking.
"There's no drug, there's no operation, there's no concept that will get rid of 30 per cent of cancers in one swat,'' he said.
"In my view, that must be the greatest breakthrough in cancer medicine that has ever occurred and ever will occur.''