Last month, National Breast Cancer Awareness Month was observed locally and nationally with appropriate fanfare and enthusiasm. November is Lung Cancer Awareness Month. I would venture that few of us, even in the healthcare professions, know of any recent or upcoming lung cancer awareness events. Yet lung cancer is, if anything, an even more virulent foe, and deserves our most focused attention as a public health scourge.
Lung cancer is by far the most common cause of cancer death in the US. This disease kills more than the next four deadly cancers combined, accounting for three times as many deaths as prostate cancer in men —and among women, lung cancer accounts for twice as many deaths as breast cancer.
Despite these sobering statistics, lung cancer research funding has been paltry in comparison with research in other cancers. When considered as research dollars spent per cancer death, breast cancer leads the pack at more than $27,000 per cancer death. By contrast, only $1,200 per cancer death was spent on lung cancer research in 2009, actually down from $1,800 per cancer death in 2005. Advocacy for increased funding for lung cancer research should be a priority.
Nonetheless, we are making some progress in the management of this malignancy. Societal imperatives to stop smoking have had an effect, and the incidence of lung cancer may be decreasing slowly as the number of smokers declines.
However, smoking remains the overwhelming causative factor for the disease. Ninety two percent of men with lung cancer and nearly 80 percent of women with lung cancer have been smokers. For non-smokers who develop lung cancer — a group that includes one in five female lung cancer patients — other likely causative factors include second hand smoke, radon exposure, and other environmental exposures (asbestos, arsenic). For smokers, the good news is that over time, smoking cessation dramatically improves the odds against developing lung cancer; but the risk does not disappear, and as many as 60 percent of lung cancers are now diagnosed in former smokers.
Recent treatment advances for lung cancer have been modest but encouraging. Surgical resection of an early lesion that has not yet spread remains the best hope for achieving cure. During the past several years we have found that chemotherapy administered to those who have undergone a curative resection further improves the chances of keeping the cancer from recurring.
For those patients who are diagnosed with stage III disease that involves lymph nodes in the central chest (the mediastinum), surgery is usually not possible, but recent advances involving the combined modality treatment of such patients with concurrent chemotherapy and radiation therapy have resulted in significant improvement in outcomes, including potential long-term survivorship. In addition, recent genetic advances allow for the identification of certain gene mutations in some lung cancers that can guide the choice of chemotherapy for optimal effectiveness against lung cancer with the least possible toxicity.
Small cell lung cancer, the most aggressive variant, was earlier considered universally fatal, but now, with chemotherapy and radiation, we can now cure as many as 25 percent of small cell lung cancer patients when the disease is confined to the chest at the time of diagnosis.
Since surgery renders the best chance for cure, and since surgery is only an option for early lesions that have not spread, early detection is critical. This is our greatest challenge with lung cancers: presently less than 20 percent of lung cancers are diagnosed early enough to allow for consideration of surgery.
A great deal of effort has been invested in devising screening programs for patients at high risk for lung cancer. Unfortunately, simple steps have been ineffective. Chest X-rays too often identify a malignant tumor only after it has spread to lymph nodes.
Sputum cytology has been too insensitive to be meaningful. Just last year, however, the National Cancer Institute announced results of a study utilizing spiral computed tomography (CT) imaging (a low dose imaging technique with about as much radiation exposure as a mammogram) in a very large population of smokers at high risk for lung cancer.
The study revealed that compared to screening with chest X-rays alone, spiral CT’s reduced the risk of death from lung cancer by 20 percent. This is the first study ever to show benefit from screening for lung cancer. Spiral CT cancer screening may be an important step forward, but like so many other advances in cancer care, the cost of such progress will pose difficult questions for public health policy. Nonetheless, research such as this must proceed if we are to continue making inroads in the management of this difficult malignancy.
Thomas Baeker, MD, a board certified oncologist and hematologist, is the medical director of Commonwealth Cancer Centers of Kentucky.