Study Finds Smokers Diagnosed with Pneumonia Are at Higher Risk of Lung Cancer

Study Finds Smokers Diagnosed with Pneumonia Are at Higher Risk of Lung Cancer

According to new research from Tel Aviv University (TAU) and Rabin Medical Center, heavy smokers who are diagnosed with pneumonia are at higher risks of developing lung cancer (LC).

Lung cancer is the most life-threatening cancer in the U.S., with a five-year survival rate of just 17 percent for patients. Smoking is the cause of nearly 85 percent of all LC cases, and only 15 percent of them are diagnosed at an early stage. Most efforts to obtain early diagnoses have been unsuccessful, mostly due to the highly aggressive nature of the disease.

The Tel Aviv research team, led by Dr. Daniel Shepshelovich, M.D., from TAU’s Sackler Faculty of Medicine, proposes that screening heavy smokers admitted to the hospital with community-acquired pneumonia (a form of pneumonia contracted by a person with little contact with the health care system) could help diagnose lung cancer earlier, thereby reducing mortality incidence. When diagnosed with pneumonia, heavy smokers are at the top of the risk groups for lung cancer and should be screened early, by chest-computer tomography.

The results of the study were published in the American Journal of Medicine, titled “High Lung Cancer Incidence in Heavy Smokers Following Hospitalization due to Pneumonia.

“Lung cancer is truly aggressive,” Shepshelovich said in a press release. “The only chance of recuperation is if it’s caught before it begins to cause any symptoms at all. The idea is to find the tumor well in advance. Previous studies have shown that a low-dose radiation CT scan conducted once a year on heavy smokers has the potential to lower lung cancer mortality rates. But this requires huge resources, and we still don’t know how it will perform in real-world conditions, outside of strictly conducted clinical trials. We want to develop a more realistic and cost-effective strategy targeting a particularly high-risk population.”

Shepshelovich’s team examined the admission files of 381 heavy smokers  with community-acquired pneumonia at the Rabin Medical Center between 2007 and 2011. They reviewed all medical files for patient demographics, smoking history, LC risk factors and the anatomical location of the pneumonia. Afterwards, the team cross-checked these data with Israel’s National Cancer Registry database, to look for new cancer diagnoses.

Additionally, the research team found that from 381 admissions of heavy smokers with pneumonia, 9 percent (31 cases) were diagnosed with lung cancer within a year after hospitalization. Lung cancer incidence was found to be significantly higher in patients admitted with upper lobe pneumonia, at 23.8 percent, and the area in the lobe affected by pneumonia was found to be the lung cancer location in 75.8 percent of the cases. The researchers are now considering taking on a larger, national, retrospective study on the subject.

“We discovered that smokers hospitalized with pneumonia are diagnosed with cancer after the infection because often the cancer masquerades as pneumonia, physically obstructing the airway and creating such an infection,” Shepshelovich said. “Considering that only 0.5 to 1 percent of smokers without pneumonia have a chance of being diagnosed with lung cancer every year, the fact that 9 percent of our study group developed lung cancer is alarming. The current diagnostic methods in place — chest X-rays, sputum cytology — sometimes find the cancerous tumors, but they do not change mortality rates.”

“In other words, people are aware that they have cancer for longer periods of time, but do not recover. This is not a solution. Smokers admitted to the hospital with pneumonia should be considered for chest-computer tomography. Only 15 percent of lung cancer cases are detected at an early stage. We want to increase that number in order to reduce mortality or, at the very least, extend lives,” Shepshelovich added.

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