Study Underscores Importance of Surveillance After Cancer

One in 12 people who survive a common cancer will develop a second, unrelated malignancy, the most common of which was lung cancer, according to a study published in the journal Cancer. Among patients who developed a second cancer, 13% died of their primary cancer and 55% died of their secondary malignancy.

The study’s lead author, Karim Chamie, MD, assistant professor of urology at the David Geffen School of Medicine at University of California Los Angeles, said the results suggest that physicians should rethink follow-up care and monitoring among cancer survivors.

“We can become so focused on surveilling our patients to see if a primary cancer recurs that we sometimes may not be aware that patients can be at risk of developing a second, unrelated cancer,” he said in a statement.

The study followed more than 2.1 million adult patients diagnosed with a primary malignancy from the 10 most common cancer sites (prostate, breast, lung, colon, rectum, bladder, uterus, kidney, melanoma, and non-Hodgkin lymphoma) and identified 170,865 (8.1%) who developed a secondary malignancy.

The patients were identified in the Surveillance, Epidemiology, and End Results (SEER) database between 1992 and 2008. The authors used bivariable and multivariable models to explore what factors were associated with the incidence of second primary malignancies and examined mortality related to first and second primary malignancies.

Survivors of bladder cancer had the highest risk of developing a second cancer, most often lung cancer, the study found. Chamie pointed out that lung cancer is a very lethal second cancer, often more lethal than the primary cancer. Thirty-four percent of bladder cancer patients who were followed for up to 20 years developed a second, unrelated cancer. Of those, 25% developed lung cancer. The study also found that a history of non-Hodgkin lymphoma and bladder cancer predicted the highest risk of developing a second cancer (including lung, prostate, and breast cancers).

The authors note that routine follow-up for bladder cancer patients does not now include a CT scan of the chest and lungs. Thus, Chamie suggested, the findings advocate for potentially adding annual CT scans of the lungs for bladder cancer survivors—especially those who smoke. He noted that his UCLA colleague Denise Aberle, MD, showed in a 2011 10-year study of high-risk patients who were heavy smokers that administering CT scans reduced lung cancer deaths by 20% compared with screening using chest x-rays.

“The hope is that if we catch some of these secondary cancers, which are much more lethal than the primary cancers, we may save many more lives down the line,” Chamie concluded.