Second Primary Malignancies After Early Detection of NSCLC

Annual screening with low-dose computed tomography (LDCT) is recommended for individuals considered to be at high risk for lung cancer.1 The rationale for screening relates to improved

survival associated with the detection of smaller, earlier stage tumors. Overall, the mean 5-year survival rate is 17% but rises to 55% among the minority of cases (16%) that are detected

while still localized.2

With the expectation that lung cancer screening will lead to an increase in the number of long-term survivors of this malignancy, a group of investigators recently completed an investigation

of the risk of second primary malignancies (SPMs) in these patients.2 Specifically, they asked if early detection and longer-term survival increase the risk of metachronous cancers in those

diagnosed with early-stage non-small cell lung cancer (NSCLC).

Researchers culled information from the Surveillance, Epidemiology, and End Results (SEER) database. Adults who had been diagnosed with stage 1a NSCLC as their first malignancy between

January 2004 and December 2010 were included. The incidence of an SPM—defined as a metachronous cancer detected 6 or more months after a diagnosis of NSCLC—was determined.

A total of 12,246 patients were included in the analysis; 43% had adenocarcinoma and 57% had squamous cell carcinoma of the lung. SPMs were detected in 11.8% of participants with

adenocarcinoma and in 11.6% of those with squamous cell carcinoma. Both groups had an approximate latency period of 34 months between primary and secondary diagnoses.

Results showed that solid-tumor SPMs, especially in the respiratory system, made up the bulk of the disease burden in both the adenocarcinoma and squamous cell carcinoma groups. Incidence of

SPMs occurred more frequently in patients >60 years old.

Interestingly, the stratification of other SPMs differed between cohorts. Those in the adenocarcinoma group were more likely to be diagnosed with gastrointestinal (GI), pancreatic, thyroid,

and female breast cancers, while those with squamous cell carcinoma were more likely to be diagnosed with urogenital, thyroid, pancreatic, and GI tract malignancies.

As early screening with LDCT increases, the study authors believe that the incidence of SPMs is likely to go up as well. “This is suggested by the improved survival of individual patients

with more time available for a second malignancy to develop,” they wrote. “This increase may reflect the systemic effect of carcinogen exposure, tumor-related genetic predisposition, and

exposure to chemotherapeutic agents or radiation.” It’s also possible that some SPMs are screening-related cancers.

Principal investigator Dipesh Uprety, MD, told MedPage Today that “more than surprised, I was disheartened with our results,” he says. “I cannot imagine how frustrated a patient would feel

if they hear that they have another cancer after having had treatment for lung cancer.”

Patient consideration is paramount for Dr. Uprety, who is a hematology and medical oncology fellow at Gundersen Health System in La Crosse, Wis. Before screening anyone, Dr. Uprety and his

colleagues encourage shared-decision making with their patients, outlining the test’s potential risks (radiation exposure, false-positive results, anxiety related to test findings, and

unnecessary testing) and benefits (decrease in lung cancer mortality).

“We recommend lung cancer screening, using LDCT, for adults ages 55 to 77 who have a smoking history of 30 or more pack-years, and are either smoking currently or have quit within the past

15 years,” notes Dr. Uprety. “Our age limit is in accordance with Medicare coverage.”

Ultimately, Dr. Uprety says, counseling on smoking cessation is of utmost importance, including helping patients set a quit date and arranging close follow-up. He adds, “For those who have

had cancers in the past, a joint approach of routine follow-up, close communication between the primary care doctor and oncologist, and a judicious, age-appropriate cancer screening may help

detect a second primary malignancy in the early stage.”