When there’s no early warning
The announcement last week that ABC News anchor Peter Jennings has lung cancer brings up a puzzling question: As doctors get better at detecting and treating other forms of the disease, such as cancers of the breast and prostate, why can’t they make similar inroads with lung cancer?
The answer is no one knows. Lung cancer kills about 163,000 Americans each year -- more than any other cancer -- and is the third-leading cause of death, after heart disease and strokes. Cancer of the lung is especially difficult to treat because by the time patients begin having symptoms, such as a prolonged cough or raspy voice, it is often too late for effective treatments, such as surgery, to work.
Doctors and researchers have been searching for decades for better screening tests for lung cancer, with little success.
Some doctors may recommend yearly chest X-rays for some patients without symptoms, especially current or former smokers. But research has shown that by the time tumors can be detected with an X-ray, the disease is often too advanced to be treatable.
Some doctors have also turned to screening tests that use CT scans to aid in the detection of smaller, early-stage lesions. But scientists say there is insufficient proof that, even if tumors can be detected earlier, it will improve mortality rates for the disease. Many experts in the field are awaiting results of a large, national study due in a few years.
A few years ago, doctors had high hopes for the drug Iressa, which showed promise in clinical trials at stopping the spread of tumors in patients with non-small-cell lung cancer. But since the chemotherapy drug went on the market two years ago, it has generally not proved to be very effective.
The U.S. Food and Drug Administration said in December that a recent clinical trial showed that the drug did not improve survival rates and that it was considering whether to pull the drug from the market.
“We have to conclude that the tools we have available in 2005 just aren’t enough to significantly combat this disease,” said Dr. W. Michael Alberts, president-elect of the American College of Chest Physicians.
Lung cancer accounts for 14% of all cancers and nearly a third of all cancer deaths. The one-year survival rate for lung cancer increased from 37% in 1975 to 42% in 2000, mostly because of improvements in surgical techniques and drug therapies. The five-year survival rate continues to hover around 15%, however, which is one of the lowest of any cancer.
Dr. John R. Balmes, a pulmonologist at UC San Francisco, said Jennings could be facing a difficult prognosis. A former heavy smoker who had struggled to quit, Jennings did not disclose details about his type of lung cancer or how advanced the disease is.
It is not encouraging, Balmes said, that Jennings’ doctors, according to a statement released by the journalist last week, have opted to begin outpatient chemotherapy this week instead of surgery. “It could mean the disease already has spread beyond the lungs and, in that case, surgery wouldn’t be enough,” he said.
Some doctors are advocating that high-risk patients, especially current and former smokers, consider getting CT scans. But many continue to discourage the tests because they don’t know how helpful they can be.
The test also comes with its own risks, including small doses of radiation, a relatively high cost and the possibility of “false positives” that could lead to unnecessary and potentially risky follow-up surgery.
Some people choose to get CT lung scans at private imaging centers, where the test costs about $300.
Many doctors hope the ongoing National Lung Screening Trial, being conducted by the National Cancer Institute, will help clarify whether the CT scan is an effective screening tool. The study is following 50,000 patients by scanning one-half with CT scans and the other with traditional X-rays. The results are not expected for several years.
Although Iressa has been a disappointment, researchers hope that a new wave of targeted therapies will eventually prove effective in treating lung cancer. The drugs, which interfere with specific molecular structures within a tumor but leave other cells untouched, have transformed treatment of several cancers. One such drug, Gleevec, has been highly effective in treating some types of leukemia.
Drug makers are rapidly pursuing more specialized cancer therapies.
In November, the FDA approved a new treatment called Tarceva, which appears to help shut down some lung tumors and produces few serious side effects. Some studies have shown the drug may extend lung cancer patients’ lives by as long as two months. Several other drugs are also in development.
Of course, doctors point out there is still only one way to significantly reduce deaths from lung cancer: persuade people to stop smoking. Up to 90% of lung cancers are believed to be associated with smoking.
“Hopefully, some people who hear about Mr. Jennings will put down their cigarettes,” Balmes said.
(BEGIN TEXT OF INFOBOX)
Where to go for support, services
* American Cancer Society offers information about various cancers, treatment, prevention and detection. Its services include a helpline of cancer information specialists at (800) ACS-2345. Or go to www.cancer.org.
* American Lung Assn. supports programs that fight lung disease and funds research into cancer and other illnesses. It also offers a lung-health call center for people with questions about disease, insurance, smoking cessation, medication and other topics at (800) 548-8252. Or go to www.lungusa.org.
* Memorial Sloan-Kettering Cancer Center is a nationally known treatment and research center in New York. Go to www.mskcc.org/mskcc.
* UCLA’s Jonsson Comprehensive Cancer Center specializes in treatment and research of various cancers.
Go to www.cancer.mednet.ucla.edu.
* USC/Norris Comprehensive Cancer Center also specializes in treatment and research of various cancers. Go to ccnt.hsc.usc.edu.