Analysis Details Incidence, Prevalence of NSCLC in the United States

A cross-sectional epidemiological US analysis revealed an overall decrease in the incidence of non–small cell lung cancer (NSCLC) between 2010 and 2017 across age and sex subgroups but showed an increased incidence of stage I NSCLC at diagnosis. The latter finding potentially reflects improved evaluation of incidental nodules, researchers wrote. Results were published in JAMA Oncology.

Globally, lung cancer is the leading cause of cancer-related deaths while NSCLC accounts for approximately 84% of all lung cancers, according to the researchers.

Despite the disease’s poor prognosis, treatment has drastically changed over the past decade thanks in part to wider lung cancer screening and improved radiation techniques.

In an effort to elucidate the most recent estimates of prevalence, incidence, and survival of patients with NSCLC, the investigators assessed deidentified data from the United States Cancer Statistics database comprising the Surveillance, Epidemiology, and End Results (SEER-18) program and the National Program of Cancer Registries (NPCR).

All individuals aged 18 and older with NSCLC diagnosed as of 2010 were included in the current analysis while “yearly incidence per 100,000 persons was age-adjusted to the 2000 US standard population,” the authors wrote. In addition, “a crude estimate of yearly prevalence per 100,000 persons was defined as the yearly incidence plus all patients who were diagnosed with NSCLC in prior years (the earliest year was 2000 when SEER-18 was established).”

Data showed that between 2010 and 2017, there were 1.28 million new NSCLC cases reported. Fifty-three percent of patients were male, and 67% were at least 65 years old.

Analyses revealed:

• From 2010 to 2017, NSCLC incidence per 100,000 decreased from 46.4 to 40.9 overall (age < 65 years: 15.5 to 13.5; age ≥ 65 years: 259.9 to 230.0)
• The incidences of stage II, IIIA, and IIIB NSCLC were stable; stage IV decreased slightly from 21.7 to 19.6; and stage I incidence increased from 10.8 to 13.2
• From 2010 to 2016, NSCLC prevalence per 100,000 increased from 175.3 to 198.3 (nationwide projection of SEER-18)
• Prevalence increased among younger patients (77.5 to 87.9) but decreased among older patients (825.1 to 812.4)
• 26.4% of patients survived 5 years, which is higher than previously reported
• The proportion of stage I NSCLC treated with radiation as single initial treatment rose markedly, from 14.7% in 2010 to 25.7% in 2016
• Patients with stage IV NSCLC 65 years or older were most likely to be untreated (38.3%)

In the SEER-NPCR database, adenocarcinoma was the most common NSCLC histologic finding, followed by squamous cell.

The investigators hypothesized the increased incidence of stage I NSCLC could be due to increased screening rates following the publication of the National Lung Screening Trial in 2011 and the US Preventive Services Task Force in 2013.

However, the overall decreased incidence of NSCLC could be attributed to tobacco control programs implemented in the last decade.

“In contrast to the overall decline in incidence, but consistent with the improvement in survival, the overall prevalence of NSCLC increased from 2010 to 2016, suggesting that patients are generally living longer after diagnosis,” the authors added.

The retrospective nature of data included in the analysis and the fact the SEER-18 database lacks a nationwide sample mark limitations to the current study.

“Despite availability of effective treatments, patients aged 65 years or older with stage IV NSCLC have the lowest 5-year survival, which may be at least partly due to undertreatment. The reasons for this should be studied further,” the researchers concluded.

Reference

Ganti AK, Klein AB, Cotarla I, Seal B, Chou E. Update of incidence, prevalence, survival and initial treatment in patients with non-small cell lung cancer in the US. JAMA Oncol. Published online October 21, 2021. doi:10.1001/jamaoncol.2021.4932