Looking to Beat Lung Cancer

Researchers continue to expand our understanding of this all-too-common cancer.

By Kari Bohlke, ScD

Lung cancer remains the leading cause of cancer death in both men and women in the United States. In 2009 an estimated 89,000 men and 70,000 women died of lung cancer. By comparison breast cancer kills roughly 40,000 U.S. women each year.[1]

So what’s the good news? Gradual progress continues to be made in understanding and treating this all-too-common disease.

Maintenance Therapy Shows Promise

Maintenance therapy refers to treatment that is given after initial treatment but before cancer progression. It is a relatively new approach to lung cancer treatment. In 2009 the chemotherapy drug Alimta® (pemetrexed) was approved as maintenance therapy for locally advanced or metastatic, nonsquamous, non–small cell lung cancer (NSCLC).

The efficacy of Alimta as maintenance therapy was assessed in a Phase III clinical trial.[2] The study enrolled more than 600 patients with Stage IIIB or IV NSCLC that had not progressed after four cycles of platinum-based chemotherapy. In addition to standard medical care, some patients were given Alimta maintenance therapy and others were given a placebo. Patients in the Alimta group lived longer than patients in the placebo group. Overall survival was 13.4 months among patients treated with Alimta compared with 10.6 months among patients treated with placebo. The benefit of Alimta maintenance therapy was limited to patients with nonsquamous NSCLC. In these patients, overall survival among those treated with Alimta maintenance was 15.5 months.

Targeted therapies such as Avastin® (bevacizumab) and Tarceva® (erlotinib) are also being explored as maintenance therapies.[3]

Research on Targeted Therapies Continues

Although chemotherapy remains the cornerstone of treatment for people with advanced lung cancer, the addition of targeted therapies can improve outcomes for some patients. Targeted therapies are anticancer drugs that interfere with specific pathways involved in cancer cell growth or survival. For patients with non–small cell lung cancer, targeted therapies that may be used at some point in the course of treatment include Avastin and Tarceva. There is some evidence that the targeted drug Erbitux® (cetuximab) may also have a role in lung cancer treatment, but this drug has not yet been approved for lung cancer. Researchers continue to explore how best to use these and other targeted therapies in combination with conventional cancer treatment such as chemotherapy and radiation therapy. Research is also focused on how to predict which patients are most likely to respond to which drugs.

What About Lung Cancer Screening?

For cancers such as breast cancer, colorectal cancer, and cervical cancer, the early detection of disease through the screening of asymptomatic individuals has contributed to decreased rates of death from the disease. Understandably, there has also been a great deal of interest in whether lung cancer screening with tests such as chest X-rays or computed tomography (CT) scans could reduce lung cancer mortality. Unfortunately, there is still no conclusive evidence that screening for lung cancer reduces the risk of death from lung cancer.

Furthermore, as is the case when screening for any disease, screening for lung cancer carries potential risks. If the screening test produces a false-positive result (for example, suggests that there is cancer when in fact there is not), it will expose the individual to unnecessary and often invasive follow-up tests. Screening may also detect some cancers that do not actually need to be detected (very slow-growing cancers that will not affect the individual’s health during his or her lifetime). Before implementing routine screening programs, therefore, it’s important to establish that screening provides benefits (most importantly, a reduced risk of death from the disease) that outweigh the potential risks.

Two large randomized trials that will help address many of the uncertainties surrounding lung cancer screening are the NELSON trial and the National Lung Cancer Screening Trial (NLST).[4] The NELSON trial, conducted in the Netherlands, Belgium, and Denmark, is comparing CT screening with no screening among current and former smokers. In the United States, the NSLT is comparing CT screening with chest X-ray screening among current and former smokers. It will be several years before the final results of these studies are available.

Prevention Is Still Key

In spite of important progress in the treatment of lung cancer, outcomes remain poor for many patients. This highlights the key role that prevention must play. Although lung cancer does occur in people who have never smoked, avoidance of tobacco smoke is the best thing we can do to reduce our risk. And if you currently smoke, it’s not too late to quit. Smoking cessation reduces your risk of developing lung cancer and can also improve your outcomes with lung cancer.

Finally, consider testing your home for radon. Radon is a radioactive gas produced by the decay of naturally occurring uranium in soil and water. In the United States, radon is the leading cause of lung cancer in nonsmokers and the second-leading cause of lung cancer overall.[5] Do-it-yourself radon test kits are available at many hardware stores, and testing can also be performed by a professional. If the test identifies high radon levels, steps to reduce radon include increasing ventilation under floors and sealing gaps and cracks in floors.

Postmenopausal Hormone Use Linked with Increased Risk of Lung Cancer Death

Ongoing follow-up of the Women’s Health Initiative clinical trial of combined postmenopausal hormonal therapy suggests that estrogen plus progestin may increase a woman’s risk of dying of lung cancer.

As women reach menopause and beyond, many experience symptoms such as hot flashes, night sweats, sleep disturbance, and vaginal dryness. Estrogen, with or without progestin, provides effective treatment for many of these symptoms, but studies have raised concerns about the health effects of postmenopausal hormonal therapy.

Results from the Women’s Health Initiative clinical trial indicated that combined estrogen plus progestin increases the risk of heart disease, breast cancer, and stroke. Combined hormonal therapy decreases the risk of bone fracture and colorectal cancer, but these benefits are thought to be outweighed by the risks for many women.[6]

Women who participated in this study continue to be followed, and researchers recently reported on the risk of lung cancer in women who took estrogen plus progestin.[6] Compared with women who were given a placebo, women who were given estrogen plus progestin were not significantly more likely to develop lung cancer but were more likely to die of lung cancer. Rates of lung cancer death were 71 percent higher among women who took estrogen plus progestin than among women who took a placebo.

Smoking Cessation After Lung Cancer Diagnosis Improves Survival

According to the results of a study published in the British Medical Journal, quitting smoking after a diagnosis of early-stage lung cancer may reduce the risk of cancer recurrence and death.[8]

To evaluate the effect of quitting smoking after a lung cancer diagnosis, researchers evaluated information from several previously published studies. Most of the studies focused on patients with early-stage lung cancer.

  • Among patients with non–small cell lung cancer, those who continued to smoke after diagnosis were almost three times more likely to die and almost twice as likely to experience a cancer recurrence as those who stopped smoking.
  • Estimated five-year survival in 65-year-old patients with early-stage non–small cell lung cancer was 33 percent among those who continued to smoke and 70 percent among those who quit smoking.
  • Among patients with limited small cell lung cancer, those who continued to smoke after diagnosis were roughly twice as likely to die and more than four times as likely to develop a second primary tumor as those who stopped smoking.
  • Estimated five-year survival in 65-year-old patients with limited small cell lung cancer was 29 percent among those who continued to smoke and 63 percent among those who quit smoking.

Although earlier smoking cessation would likely provide greater benefits, the results of this review suggest that smoking cessation after a diagnosis of early-stage lung cancer may improve outcome.

Information About Lung Cancer Clinical Trials

Symptoms of Lung Cancer[9]

  • Cough that gets worse or does not go away
  • Breathing trouble, such as shortness of breath
  • Constant chest pain
  • Coughing up blood
  • Hoarse voice
  • Frequent lung infections, such as pneumonia
  • Feeling very tired all the time
  • Weight loss with no known cause

Help with Smoking Cessation

Radon Information from the U.S. Environmental Protection Agency

References

[1]. Cancer Facts and Figures 2009. American Cancer Society Web site. Available at: http://www.cancer.org/downloads/STT/500809web.pdf. Accessed March 27, 2010.

[2]. Ciuleanu T, Brodowicz T, Zielinski C, et al. Maintenance pemetrexed plus best supportive care versus placebo plus best supportive care for non-small-cell lung cancer: a randomised, double-blind, phase 3 study. Lancet. 2009;374(9699):1432-40.

[3]. Miller VA, O’Connor P, Soh C, et al. A randomized, double-blind, placebo-controlled, phase IIIb trial (ATLAS) comparing bevacizumab (B) therapy with or without erlotinib (E) after completion of chemotherapy with B for first-line treatment of locally advanced, recurrent, or metastatic non-small cell lung cancer (NSCLC). Paper presented at: 45th Annual Meeting of the American Society of Clinical Oncology; May 29-June 2, 2009; Orlando, Florida. Abstract  LBA8002.

[4]. Field JK, Duffy SW. Lung cancer screening: the way forward. British Journal of Cancer. 2008;99(4):557-62.

[5]. Radon: Health Risks. U.S. Environmental Protection Agency Web site. Available at: http://www.epa.gov/radon/healthrisks.html. Accessed March 27, 2010.

[6]. Rossouw JE, Anderson GL, Prentice RL, et al. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results from the Women’s Health Initiative randomized controlled trial. Journal of the American Medical Association. 2002;288(3):321-33.

[7]. Chlebowski RT, Schwartz AG, Wakelee H, et al. Estrogen plus progestin and lung cancer in postmenopausal women (Women’s Health Initiative trial): a post-hoc analysis of a randomised controlled trial. Lancet. 2009;374(9697):1243-51.

[8]. Parsons A, Begh R, Aveyard P. Influence of smoking cessation after diagnosis of early stage lung cancer on prognosis: systematic review of observational studies with meta-analysis. British Medical Journal [early online publication]. January 21, 2010.

[9]. What You Need to Know About™ Lung Cancer. National Cancer Institute Web site. http://www.cancer.gov/cancertopics/wyntk/lung/page6. Accessed March 27, 2010.