Study Finds Declining SCLC Incidence, but Stagnant Survival Rates

The incidence of small cell lung cancer (SCLC) has steadily declined in the US over the past 2 decades, largely due to reduced smoking rates, but survival outcomes remain largely unchanged, according to a new study published in Cancer Medicine.¹

The analysis, which examined data from the Surveillance, Epidemiology, and End Results (SEER) database between 2000 and 2020, highlights both the progress in cancer prevention and the urgent need for more effective treatment options.

Despite the implementation of CT lung screening in 2013, most patients already had distant metastatic disease at the time of diagnosis. | Image credit: Dragana Gordic – stock.adobe.com

The researchers found that the age-adjusted incidence rate of SCLC decreased by an average of 3% per year, from 9 per 100,000 people in 2000, to 4.6 in 2020. This decline was consistent across all demographic groups, including different races, sexes, and age categories. Incidence-based mortality rates also decreased, from 6.6 per 100,000 in 2005, to 3.5 in 2020. However, while fewer people are being diagnosed with SCLC, survival rates have shown only minor improvements. The 1-year relative survival rate increased slightly from 33.1% in 2000 to 35.3% in 2019, while the 1-year observed survival rose from 32.4% to 34.5% over the same period.

“Since SCLC almost always occurs in smokers, the decrease in smoking prevalence in the United States, predominately driven by implantation of smoking-related policies is likely responsible for this notable decline,” the authors said.

SCLC is a particularly aggressive form of lung cancer, with nearly 60% of patients presenting with metastatic disease at diagnosis.² For years, platinum-etoposide chemotherapy has been the standard treatment, offering strong initial responses but limited long-term survival.³ More recently, the addition of immune checkpoint inhibitors (ICIs) such as atezolizumab and durvalumab has provided some improvement in extensive-stage SCLC, yet their impact on long-term survival remains modest.¹

They also examined the impact of lung cancer screening efforts, particularly the implementation of low-dose computed tomography (CT) scans for high-risk individuals. While screening has led to earlier detection of non–small cell lung cancer, its effectiveness for SCLC is less clear due to the rapid progression of the disease. Despite the implementation of CT lung screening in 2013, most patients (55.9%) in the study already had distant metastatic disease at the time of diagnosis.^4,1 According to the authors, this indicates that annual CT screening may not be the most effective tool for detecting SCLC early, as the cancer's aggressive progression and high likelihood of metastasizing within a year may outpace the 1-year screening interval.

At the same time, the study found a slight increase in the diagnosis of localized SCLC and a corresponding decline in metastatic cases over time, particularly after 2013. While the trend was slow before 2013—potentially due to the growing use of diagnostic CT scans—the more noticeable shift afterward suggests that screening may be helping detect some cases at an earlier stage.

“Moreover, advancements in radiation techniques, early-stage at diagnosis with screening CT scans, may have improved survival for patients with limited-stage disease,” the study authors added. “Population-based studies to assess the survival benefit of improved cancer care, enhanced radiation techniques and the introduction of immunotherapy are lacking.”

The study’s limitations include the retrospective nature of SEER data, which does not capture detailed treatment regimens or emerging therapies in real time. Additionally, data before 2004 lacked complete staging information, limiting some analyses.

References

1. Uprety D, Seaton R, Niroula A, Hadid T, Parikh K, Ruterbusch JJ. Trends in the incidence and survival outcomes in patients with small cell lung cancer in the United States: an analysis of the SEER database. Cancer Med. 2025;14(3):e70608. doi:10.1002/cam4.70608
2. Rudin CM, Brambilla E, Faivre-Finn C, Sage J. Small-cell lung cancer. Nat Rev Dis Primers. 2021;7(1):3. doi:10.1038/s41572-020-00235-0
3. Farid S, Liu SV. Chemo-immunotherapy as first-line treatment for small-cell lung cancer. Ther Adv Med Oncol. 2020;12:1758835920980365. doi:10.1177/1758835920980365
4. Moyer VA; U.S. Preventive Services Task Force. screening for lung cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2014;160(5):330-338. doi:10.7326/M13-2771