Fewer than half of patients with small-cell lung cancer undergo treatment, and even fewer patients are treated with more than one line of therapy, according to study findings presented at the 2022 American Society of Clinical Oncology (ASCO) annual meeting.

“Characterizing changes in the incident small cell lung cancer (SCLC) patient population and SCLC treatment landscape is essential for understanding drivers of outcomes among patients diagnosed with SCLC,” Robert A. Ramirez, DO, and colleagues wrote. “The objective of this study was to examine trends in patient characteristics and treatment patterns for SCLC in a Medicare population.”

Dr. Ramirez and colleagues performed a retrospective analysis using SEER Medicare-linked data. Study participants had a recorded diagnosis of SCLC between January 1, 2007 and December 31, 2017 and were aged 65 and older at the time of diagnosis. The investigators stratified patient characteristics and treatment patterns based on year of SCLC diagnosis.

In total, 13,516 patients were included in the study. More than half of participants (57.7%) were women and most (89.5%) were White. The mean age of patients was 74 and 45.6% had a history of tobacco use.

Proportion of Treated Patients Increases, but Unmet Needs Remain

Most patients (73.1%) were diagnosed with stage 4 disease, and half of the study population (55.4%) started first-line treatment. Mean time from diagnosis to first-line treatment was 6 weeks.

Only 36.7% of patients starting first-line treatment moved onto second-line therapy, according to the study results. Platinum-based chemotherapy was the most frequently used first-line regimen (91.3%), and 44.7% of patients were treated with monotherapy in second-line treatment.

“Over time, the demographic characteristics of patients diagnosed with SCLC [were] fairly stable, with the exception of patients reporting a history of tobacco use, which more than tripled, increasing from 19.3% to 67.7% between 2007 and 2017,” Dr. Ramirez and colleagues wrote. “Between 2007 and 2017, the share of SCLC patients initiating [first-line] treatment increased 8.2%, from 53.8% to 58.2%, and the share initiating [second-line treatment] fluctuated between 35% and 39%.”

Platinum-based chemotherapy was regularly used by almost all patients (88.7% to 96.6%) during first-line treatment throughout the study. The use of checkpoint inhibitors in second-line treatment started in 2015 and became the most frequently used second-line therapy, after platinum-based chemotherapy, by 2017, at which point 41.5% of patients were treated with a checkpoint inhibitor in second-line therapy.

“While an increasing share of SCLC patients are pursuing treatment, less than 60% of SCLC patients receive any anticancer therapy,” Dr. Ramirez and colleagues wrote. “Fewer still receive more than one line of treatment, highlighting the ongoing need for effective therapies for SCLC.”