Smoking a significant predictor of lung cancer recurrence in survivors

A new study has shown that many lung cancer survivors are at high risk for developing another lung cancer or having their cancer return after completing treatment. Conducted by researchers in the U.S., the study specifically looked at lung cancer survivors from three different institutions who had shown no further evidence of having the disease after completing the required treatment for lung cancer.

The study will be presented at the ATS 2015 International Conference.

"We looked closely at risk factors that may help in predicting cancer recurrence in lung cancer survivors," said study lead author Samjot Dhillon, MD. "What we learned is that patients with a history of lung cancer should have close long-term surveillance so their doctor can detect early on if the cancer is recurring or if there is another cancer developing."

The research looked at 192 lung cancer survivors who underwent surveillance with CT scans of their chest and autofluorescence bronchoscopy (AFB) for a mean duration of close to 8 and a half years. AFB allows doctors to see premalignant and early malignant lesions in the central airways while CT scans can reveal large lymph nodes in the chest or nodules inside the lungs which could be due to cancer. This means both CT and AFB may allow detection of lung cancer in early stages.

They also looked at information about major risk factors to see if there was a connection between them and cancer recurrence. Those factors included: smoking status, as well as how many packs they smoke per year; prior cancers; respiratory disease; asbestos exposure; and if there was a family history of lung cancer.

What they found was that 38% had developed recurrent or another lung cancer during this period. Further research analyzing the significant factors for predicting lung cancer recurrence indicated that those factors were: having recurrence of another non-lung cancer; presence of a nodule on a CT scan of chest, regardless of its size or location; finding premalignant lesions called "metaplasia" on three AFB exams anywhere in central airway; and how long the patients had been smoking. In fact, for every additional pack a patient smoked per year, it increased the risk of having lung cancer again by 1%.

This study demonstrates that lung cancer survivors need to be monitored closely by their doctors to detect if their lung cancer is recurring or if another is developing.

"Along with close medical surveillance for lung cancer recurrence, it is also important for patients to stop smoking as soon as possible since this is a known risk," said Dhillon. "Every additional pack per year of smoking is associated with further increased risk of cancer recurrence."