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BY OUR CORRESPONDENT
29 October,2006: Early CT scans can prevent nearly eighty percent of deaths caused by lung cancer, reveals a new study published in The New England Journal of Medicine.
Lung cancer kills more than 160,000 people a year. The figures are particularly alarming while death rates for other cancers have fallen.
For long, doctors have thought there was little they could do for lung cancer, but now with more sensitive scans, many are rethinking that view. Millions of lives could be saved by detecting lung cancer early with annual CT scans and treating it immediately, when it can still be cured, says the study by researchers at NewYork-Presbyterian/Weill Cornell hospital.
“You could prevent 80 percent of deaths,” said the study’s lead author, Dr. Claudia Henschke, a professor of radiology and cardiothoracic surgery at Weill Cornell Medical College.
The study involved more than 31,000 people in seven countries. The participants included smokers and former smokers, but also included people in Japan who had never smoked but had the scans as part of annual physical exams.
The scans found 484 lung cancers, 412 of which were at a very early stage. Then the researchers tracked those cancer patients for an average of about three years after the cancer was detected. After three years, most patients were still alive. The researchers projected that more than 80 percent of those with early-stage cancer would live at least 10 years after their cancer was diagnosed.
Medical experts and a patient advocacy group say that because this study is so much bigger than previous studies and so carefully done, it should change the testing landscape, while others say that it did not include comparison groups to demonstrate clearly that there is any benefit from annual CT exams.
Cancer specialists have long known that there are cancers of all types — and lung cancers are no exception — that stop growing on their own, or that grow so slowly that they never cause problems. So, some ask, how many of the people said to be cured were never in danger? And how often will people have operations that can involve removing part of a lung, which is risky in itself, when their cancer was not lethal?
The problem, as with other cancer scans, is that science cannot always tell the difference between cancers that will stop and those that will not.
The researchers also ask another question: How often did the scans find cancers early but without affecting the person’s life expectancy?
“Everyone knows we can pick up things better with screening,” said Dr. Elliott Fishman, a professor of radiology and oncology at Johns Hopkins Hospital in Baltimore. “But is picking up the same thing as curing? If I pick up a tumor that is one centimeter today and you live five years or I pick it up four years later and you live one year, it’s the same thing.”
Even evaluating patients with suspicious CT results can be risky, more dangerous, say, than evaluating women with suspicious lumps on a mammogram, said Dr. David Johnson, deputy director of the cancer center at Vanderbilt University and a past president of the American Society of Clinical Oncology.
More definitive answers about the value of CT testing may come in a few years when another study, by the National Cancer Institute, is over. It randomly assigned its nearly 55,000 participants, smokers or former smokers, to have annual CT scans or, for comparison, chest X-rays. Based on previous studies, many researchers consider chest X-rays largely ineffective for early diagnosis of the cancer, so it can serve as a placebo control in this study.
Another institute study is assessing chest X-rays by randomly assigning participants to have an annual X-rays or to have no screening.
In the meantime, cancer specialists say doctors and their patients must decide, on an individual basis, what to do. They could wait for the clinical trials to be completed, or they could decide to have scans now, while the data may not be ideal.
And the scans can be expensive. Dr. Howard Forman, a professor of diagnostic radiology at Yale, says that Yale charges $802.39 for the scan and the doctor’s interpretation.
And while many insurers do not pay for CT lung cancer screening tests, that may change, Dr. Forman said. He said he did not find this study to be convincing — like others, he said he needed to see control group data.
BY OUR PHARMA CORRESPONDENT |
