Mohammad Khan, MD, with Hematology and Oncology with Memorial Medical Group, spoke to Sulphur Rotarians Wednesday about lung cancer.
Lung cancer is the most common cause of cancer-related deaths in the United States, with a quarter of a million diagnoses annually. About 160,000 of those diagnosed die. Worldwide, Khan said about 1.6 million people die from lung cancer a year.
Khan said only 60 percent of patients diagnosed with stage one lung cancer survive five years. The five year survival rate for patients diagnosed with stage four lung cancer is only 18 percent.
“It has such a high risk of recurrence after the first two years of diagnosis,” he said. “What we’ve learned over the course of the past decade is that, for lung cancer, prevention is going to be the key.” He said 85-95 percent of lung cancers are attributable to smoking. “So if you can cut down on the smoking, you’re certainly going to reduce the incidence of patients getting cancer,” he said. Khan said lung cancer rates are in decline in the U.S., mostly due to a decrease in smoking. But as much as 20 percent of the population is still lighting up. “The sad thing about lung cancer is that once it is diagnosed, about 75 percent of those are diagnosed at a such late stage they’re not receptive to surgery,” he said.
Khan said that even though the risk of lung cancer doesn’t disappear immediately after a patient quits smoking, it does steadily decrease over time. “It’s always beneficial to tell your patients to stop smoking,” he said. “Because we know they are also preventing other issues like cardiovascular disease.”
According to Khan, doctors are seeing an increase in the incidence of lung cancer in non-smokers, particularly women. “A lot of these are patients who’ve been exposed to second-hand smoke,” he said. “We’re seeing about 30 percent incidence in patients who’ve never even smoked one cigarette in their lives getting lung cancer now,” he said. Khan said he saw a non-smoker recently who had been diagnosed with stage four lung cancer at the age of 44. “But she spent the latter part of 15 years working in Bingo halls.” he said. “You don’t have to actually smoke to get cancer.”
Khan said that while only 10 percent of smokers develop lung cancer or emphysema, there is an “exponential increase in the incidence of lung cancer depending on the rate of use.”
Khan said the second biggest chemical culprit in causing lung cancer is asbestos, and smokers exposed to asbestos see their risk of developing lung cancer increase by as much as 70 percent.
Khan said that prostate, colon, and breast screenings are useful to doctors in diagnosing cancer in its early stages. “Like in colon cancer, most cancers arise as polyps,” he said. Those polyps are surgically removed, leading to a lower likelihood of cancer in the organ. But lung cancer screenings are not as successful. Khan said there have been several studies that collected sputum, a mixture of saliva and mucus, from high risk patients who smoked and administered three annual chest x-rays, to see if it were possible to detect lung cancer at an earlier stage. “None of those studies really ever panned out,” he said. “They didn’t pick up lung cancer any earlier than not doing the studies at all.”
Recently a lung screening trial, performed across 34 academic centers in the U.S. with 54,000 high risk patients administered a high resolution, low dose CT scan (no intravenous contrast was administered and the radiation dose was low) for three years in a row. Khan said malignant nodules were detected at a much higher percentage than traditional screening in patients who were able to get three successive scans. “Those patients were able to go to surgery much earlier to give them the best chance of a cure,” said Khan. “You’re converting a lot of the stage 3, stage 4 cancers that may have been diagnosed three or four years down the road, to stage 1 and 2, where you’re curing 60-70 percent of the patients.” Khan said the screenings are successful enough that insurance companies are now beginning to pay for them. He advised that while beneficial, there are some drawbacks to CT scans. Patients are exposed to radiation and there is the possibility of false positives when radiology technicians aren’t trained to accurately identify malignant nodules. False positives lead to unnecessary testing, surgery, and anxiety, Khan said.
The trial defined high risk patients as those who are between the ages of 55 and 74, who has smoked at least one pack a day for the past 30 years; or who stopped smoking within the last 15 years.
Dr. Khan has a Sulphur office at 1327 Stelly Lane, Suite 3 and can be reached by calling 337-494-6768.