In a study reported in JAMA Oncology, Apar Kishor Ganti, MD, MS, and colleagues found that the incidence of non–small cell lung cancer (NSCLC) has decreased in the United States in recent years. They also found that prevalence has increased, likely in association with more effective treatment and longer survival, and that a small increase in diagnosis at earlier stages has also occurred.
Apar Kishor Ganti, MD, MS
The cross-sectional epidemiologic analysis used the most recently released data from U.S. cancer registries. NSCLC incidence estimates were obtained from the population-based U.S. Cancer Statistics database for 2010 to 2017, comprising the Surveillance, Epidemiology, and End Results (SEER) program and National Program of Cancer Registries (NPCR). Data on incidence, prevalence, survival, and initial treatment according to NSCLC stage were obtained from the SEER-18 database. Incidence data were available through 2017; data on other factors were available through 2016.
Key Findings
On the basis of SEER-NPCR data, a total of 1.28 million new NSCLC cases occurred during 2010 to 2017 (53% in male patients; 67% in those aged ≥ 65 years). Between 2010 and 2017, NSCLC cases per 100,000 population decreased from 46.4 to 40.9 overall, including from 15.5 to 13.5 among individuals aged < 65 years and 259.9 to 230.0 among those aged ≥ 65 years.
Based on SEER-18 data, the incidence of stage II, IIIA, and IIIB disease was stable between 2010 and 2017, whereas the incidence of stage IV disease decreased from 21.7 to 19.6/100,000 and the incidence of stage I disease increased from 10.8 to 13.2/100,000. As stated by the investigators, the increased incidence of disease diagnosed at stage I likely reflects evaluation of incidental nodules detected outside of the lung cancer screening setting.
They noted that the Centers for Medicare and Medicaid Services National Coverage Decision to fund screening was implemented in 2015, but that awareness of the benefits of screening from the publication of the National Lung Screening Trial in 2011 likely encouraged investigation of incidentally identified nodules. In an analysis of Medicare part B patients, they found that year-on-year stage I disease incidence increased by 1.9%, 2.03%, and 3.03% from 2015 to 2017, reflecting increases in the proportion of patients undergoing screening.
Based on SEER-18 data, NSCLC prevalence increased from 175.3 to 198.3/100,000 between 2010 and 2016; prevalence increased from 77.5 to 87.9/100,000 among those aged < 65 years and decreased from 825.1 to 812.4/100,000 in older patients.
Based on SEER-18 data, 5-year survival among all patients was 26.4%, a rate higher than that previously reported.
Treatment trends included an increase in proportion of patients with stage I disease receiving radiation as single initial treatment from 14.7% in 2010 to 25.7% in 2016. A higher proportion of patients with stage IV disease aged ≥ 65 years received no treatment vs younger patients (38.3% vs 22.8%).
The investigators concluded, “The findings of this cross-sectional epidemiological analysis suggest that the increased incidence of stage I NSCLC at diagnosis likely reflected improved evaluation of incidental nodules. A smaller proportion of patients aged ≥ 65 years with stage IV NSCLC were treated. Earlier detection and availability of effective treatments may underlie increased overall NSCLC prevalence, and higher than previously reported survival.”
Editorial
James L. Mulshine, MD
In an editorial accompanying the article by Ganti et al, James L. Mulshine, MD, and Bruce Pyenson, FSA, MAAA, commented that the findings in the study are of concern, providing evidence of the slow and inconsistent implementation of lung cancer screening and the need for its wide-scale use. They noted the plausibility that the small increase in diagnosis of earlier-stage disease over the study period reflected investigation of incidental findings of pulmonary nodules (with approximately 1.5 million such findings being made annually outside of the lung cancer screening setting), given the time at which screening became funded and its slow uptake thereafter.
They stated, “Lung cancer screening succeeds because it shifts the disease stage in which cancer is diagnosed, and screening-detected lung cancer is, across a population, diagnosed at an earlier stage than symptomatically detected lung cancer. If a higher portion of incident lung cancers is screening-detected, we believe that is an indication that the incidence has shifted to earlier disease stages, which means a greater potential exists for curative intervention…. Now is the time for a concerted push for lung cancer screening implementation.”
Dr. Ganti, of the Division of Oncology and Hematology, University of Nebraska Medical Center, Omaha, is the corresponding author for the JAMA Oncology article. Dr. Mulshine, of Rush Medical College, is the corresponding author for the accompanying editorial.
Disclosure: The study was funded by AstraZeneca. For full disclosures of the study authors, visit jamanetwork.com.
