Harvard Researchers Say Lung Cancer Is Easier To Beat In Summer

By Linda Orlando

According to the American Cancer Society, more than 170,000 Americans will be diagnosed with lung cancer this year, and 60% of those diagnosed will die within a year. For 75% of those diagnosed, the disease will prove fatal within the first two years after they are diagnosed. Lung cancer is the deadliest of all cancers, and more than 160,000 people die from the disease each year. The National Cancer Institute says that symptoms of lung cancer can include a cough that doesn’t go away or worsens over time, coughing up blood, chest pain, hoarseness or wheezing, and shortness of breath. Although lung cancer can be caused or exacerbated by exposure to secondhand smoke, radon, asbestos, or certain air pollutants, the most common cause of lung cancer by far is smoking.

At the April 18 annual meeting of the American Association for Cancer Research in Anaheim, California, researchers from Harvard University presented findings that people who had surgery for early-stage lung cancer fared better afterward if they had their surgery during a sunnier time of the year. Results were also better than average for patients who had a high intake of vitamin D before surgery. In fact, those who underwent surgery in very sunny months and also had a high intake of Vitamin D were more than twice as likely to pass the five-year post-op survival mark than those patients who had their surgery during the winter and had a low vitamin D intake.

The human body naturally produces vitamin D after exposure to the sun, and researchers wanted to see what effect the sun and vitamin D might have on cancer treatment. Dr. David Christiani, a professor of epidemiology at the Harvard School of Public Health, put together a team of researchers to study 456 lung cancer patients, their treatment, and their survival rates. The average age of the people in the study was 69, 40% of them were current smokers, and all had early stage non-small-cell lung cancer. Of the patients studied, 80% had stage 1 cancer and the remaining 20% had stage II cancer, a more advanced stage of the disease. Researchers tracked their treatments, their diet, and the details and dates of their surgeries. All of the patients in the study had surgery to remove their cancer, 9% also underwent radiation treatment, and 1% received chemotherapy. Age, smoking habits, and stage of the cancer when diagnosed were also risk factors for dying, so researchers adjusted for such factors in analyzing the results of the study.

After five years of being studied, 234 of the patients had died. The five-year survival rates were 25% higher for patients whose surgery was performed in the spring, summer, or fall, when compared to those who had their surgery in the winter. And according to the review of dietary information for 323 of the study participants, those with the highest intake of vitamin D were 28% less likely to die following surgery. When researchers combined history of vitamin D intake with the time of year their surgery was performed, they found a 72% survival rate five years after surgery for those who had their surgery in the summer and had the highest vitamin D intake. For those patients who had winter surgery and a low vitamin D intake, the survival rate five years post-op was only 30%.

The Harvard study did not research the specific mechanism by which vitamin D might increase the odds of lung cancer patient survival. However, other studies have shown that vitamin D may have anti-proliferative and anti-invasive properties, meaning that vitamin D may modify the way lung cancer tumor cells grow so they are less likely to invade other parts of the body. "The take-home message from this study is that if these findings hold up, a relatively simple intervention could have a relatively large impact," said Christiani, the principal investigator in the study. "This study showed a pretty strong relationship between vitamin D intake or season and disease-free and overall survival." However, both the researchers and other experts in the field of lung cancer and other cancers stressed that the findings should not encourage patients to postpone needed surgery just to wait for a sunnier season. Dr. Jay Brooks, chairman of hematology and oncology at the Ochsner Clinic Foundation Hospital in New Orleans, points out that studies performed in the past have seemed to show significant health benefits for other vitamins, but the findings didn’t pan out after additional research. In terms of the Harvard study, Brooks adds, "This is an interesting observation, but it won't influence the way I would practice today." Because survival chances are better if lung cancer is treated immediately upon diagnosis, Brooks cautions, "People shouldn’t wait to get surgery."

Researchers involved in the study concur with Brooks. "This study in no way suggests that people should try to time their cancer surgeries for a particular season. But, if validated, it may mean that increasing a patient's use of vitamin D before such surgery could offer a survival benefit," said Dr. Wei Zhou, one of Christiani's Harvard colleagues.