Click to Enlarge: (A) Proportional Incidence of SCLC relative to all lung cancer from 2000 to 2019. (B) Joinpoint regression analysis of age-adjusted incidence rates of all lung cancers, NSCLC, and SCLC from 2000 to 2019.
Source: JTO Clinical and Research Reports
ANN ARBOR, MI — From the late 1980s to 2000, small-cell lung cancer (SCLC) made up a decreasing proportion of lung cancer cases in the United States. At the same time, survival outcomes in SCLC did not improve due to few treatment advances.
A recent review from the University of Michigan-Michigan Medicine sought to determine whether these trends continued into more recent decades, prior to the Food and Drug Administration approval of immunotherapy for SCLC in 2019. The study team evaluated the incidence and survival of SCLC from 2000 to 2019 in the United States, with a special focus on gender and racial subgroups.
In the study published in the April 2025 issue of JTO Clinical and Research Reports, the authors used the United States Surveillance, Epidemiology, and End Results 17 database, evaluating the incidence of SCLC and NSCLC from 2000 to 2019. Demographic, staging, and survival data were collected for patients with SCLC by comparing the incidence and outcomes across groups.
The results indicated that the percentage of SCLC among all newly diagnosed lung cancer cases decreased from 14.5% in 2000 to 11.8% in 2019.
“A decrease in SCLC incidence was observed in all sex and racial subgroups, but was earlier and steeper in men than in women,” the researchers explained. “This has resulted in a shift in the male-to-female ratio from 1.14:1 in 2000 to 0.93:1 in 2019. Among the racial subgroups, the incidence of SCLC declined most slowly in non-Hispanic whites and most rapidly in non-Hispanic Asians and Pacific Islanders.”
They added that a decline was documented in limited-stage SCLC at diagnosis, from 31.1% in 2000 to 26.4% in 2019, noting, “Minimal improvement was observed in survival regardless of patient characteristics or stage.”
“In the preimmunotherapy era of 2000 to 2019, the incidence of SCLC continued to decline in both sexes and all racial subgroups,” the authors concluded. “The male-to-female ratio continued to narrow, with women outnumbering men in the most recent years. The proportion of patients with limited-stage disease continues to decline, likely because of improved staging procedures. The outcomes improved slightly but remained poor, highlighting the need for more effective treatment strategies.”
The study pointed out that, despite recent advances in treatment and early detection, lung cancer remains the most common cause of cancer-related death worldwide. SCLC, meanwhile, makes up only 10% to 20% of lung cancer cases but is considered to be especially aggressive with persistently poor outcomes.
“SCLC is characterized by highly proliferative neuroendocrine cells forming rapidly progressive tumors, which typically develop in the central airways of heavy smokers, and have a predisposition for early metastasis,” the authors advised.
For the past 60 years, the VA Lung Cancer Study Group system has been used to stage SCLC, with limited-stage SCLC (LS-SCLC) being confined within a single hemithorax and a safe radiotherapy field, and extensive-stage SCLC (ES-SCLC) typically characterized by distant metastases.
The researchers explained that, with modern chemotherapy and radiotherapy, SCLC has proven extremely responsive to initial treatment. Most patients relapse quickly, however, and the five-year survival rates remain low regardless of the disease stage or treatment, they added.
The incidence of SCLC has decreased since the 1965 when the Surgeon General report on the health dangers of smoking was released, and the subsequent decline in cigarette use in the United States occurred.
According to prior reviews of SCLC data in the Surveillance, Epidemiology, and End Results (SEER) database from 1973 to 2002, the absolute incidence of SCLC and the proportional incidence of SCLC (the percentage of SCLC among all new lung cancer diagnoses) peaked in the late 1980s and then steadily declined through 2002, according to background information in the article.
“Nevertheless, there was only minimal improvement in survival regardless of stage. Advances that may have affected survival during this period include the advent of the cisplatin and etoposide regimen in the 1980s and the routine use of concurrent chemoradiotherapy for LS-SCLC in the 1990s.”
The authors suggested that their data set the baseline for future evaluation of SCLC trends after the recent incorporation of immunotherapy into the standard treatment for all stages of SCLC.
- Wells LE, Cohen S, Brennan B, Banerjee M, Kalemkerian GP. Epidemiology of SCLC in the United States From 2000 to 2019: A Study Utilizing the Surveillance, Epidemiology, and End Results Registry. JTO Clin Res Rep. 2025 Jan 20;6(4):100799. doi: 10.1016/j.jtocrr.2025.100799. PMID: 40104389; PMCID: PMC11914508.
