Missed Opportunities for Early Lung Cancer Detection

SAN DIEGO — New research highlights a mismatch between lung cancer screening eligibility criteria and actual lung cancer risk, which means many patients who develop lung cancer are not captured by the current criteria and don’t receive early screening.

The analysis revealed that only 6% patients with lung cancer were screened with low-dose CT before their cancer was diagnosed.

Of those who were unscreened, more than half (52%) were ineligible for screening based on the US Preventive Services Task Force 2021 criteria, and approximately 41% were eligible but did not get screened before diagnosis.

“A mismatch between eligibility criteria and true lung cancer risk is actually a bigger barrier than being eligible and not getting a screening test,” Raymond Osarogiagbon, MD, with Baptist Cancer Center, Memphis, Tennessee, said during his presentation at the World Conference on Lung Cancer (WCLC) 2024.

“Expanding screening criteria and improving access to incidental detection programs may help identify high-risk patients earlier, improving survival rates,” Osarogiagbon said.

Novel Approach

Screening criteria identifies at-risk candidates based on their age — 50-80 years — and smoking history, but “we’re kind of guessing” who’s at risk, Osarogiagbon explained.

In the current study, the critical assumption was that “the diagnosis of lung cancer, albeit retrospective, is the truest indicator of lung cancer risk,” Osarogiagbon said. If you’ve got lung cancer, “by definition, you were at risk.”

The researchers created a prospective observational cohort, Detecting Early Lung Cancer (DELUGE) among patients in the Mississippi Delta, using data from those managed through the low-dose CT or Lung Nodule Program at Baptist Memorial Health Care Corporation centers. (The Lung Nodule Program is a safety net created for when radiologic studies revealed a potentially malignant lung lesion irrespective of indication, other than known or suspected cancer.)

The researchers combined the DELUGE cohort with a prospective cohort from a Multidisciplinary Thoracic Oncology Care Program.

Among a total of 1904 patients with lung cancer, only 122 were screened, 788 were unscreened, and 994 were ineligible for screening.

Among ineligible patients, 20% had never smoked, 21% were considered too old (older than 80 years), 7% were considered too young (younger than 50 years), 31% had quit smoking more than 15 years prior, 14% had a less than a 20 pack-year smoking history, and 35% had missing data.

Notably, one third of the eligible but unscreened cohort had clinical encounters 1-3 years before their lung cancer diagnosis.

“This is truly a missed opportunity and begins to tell us some of the things that we may need to do to overcome the barrier to access,” Osarogiagbon said.

Tumor stage, surgical resection rates, and 5-year survival rates were all better among screened patients who had lung cancer.

The 5-year overall survival rates were 77% vs 45% in the screened vs unscreened group, respectively, and 50% in the ineligible group.

Surprisingly, survival in the two “disadvantaged” cohorts was actually “better than you would expect,” given the aggregate US lung cancer survival rate of about 25%, Osarogiagbon said.

Survival was also better among patients with lung cancer who were followed or “rescued” by the project’s incidental Lung Nodule Program.

In unscreened rescued and ineligible rescued patients, the 5-year survival rates were 61% and 60%, respectively, compared with the 5-year survival rates of 34% and 42% for unscreened/not rescued and ineligible/not rescued patients. Moreover, stage and surgical resection rates were better among the “rescued” patients.

Overall, Osarogiagbon said that research is needed to “expand the reach of lung cancer screening across the full spectrum of persons truly at risk. Parallel efforts are needed to increase participation among currently screen-eligible persons.”

Study discussant Betty Tong, MD, with Duke University Medical Center, Durham, North Carolina, said that “we all know that survival for patients with lung cancer is best when the tumor found and treated at its earliest stages. Obviously, that’s a lot easier said than done.”

While low-dose CT screening is one way to improve early detection and diagnosis, “I think our colleagues here have shown us that there are [other] ways in which we can continue to move the field forward,” she said. “Through their incidental nodule program…they’ve rescued a number of patients and found more tumors at early stages. Patients who were not rescued had more tumors diagnosed at advanced stages.”

It’s not surprising that patients who were rescued were more likely to be treated with surgery and had better 5-year survival rates, she added.

Overall, Tong said this study “provides more fodder for us to continue to advocate for implementation of screening in eligible individuals.”

Osarogiagbon disclosed relationships with Eli Lilly, Pfizer, Gilead Sciences, BridgeBio Pharma Inc., AstraZeneca, Triptych Healthcare Partners, GE Healthcare, and Median. Tong had no relevant disclosures.