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Sebastian Schmidt: Lung cancer screening – results from Croatia

Photo taken from Sebastian Schmidt/LinkedIn

Mar 7, 2024, 05:17

Sebastian Schmidt: Lung cancer screening – results from Croatia

Sebastian Schmidt, Head of Strategy and Medical Affairs Computed Tomography at Siemens Healthineers, shared a post on LinkedIn:

“Lung cancer screening – results from Croatia:

At the ongoing ECR, MIroslav Samarzija showed results from the lung cancer screening program in Croatia, as part of the SOLACE Project presentation (which gets an own summary).

He showed results of about 27.000 screening CT scans, mostly (3/4) baseline scans. They found lung cancer in about 1.2% of participants. 47% were in stage I and II, 54% of these lung cancer patients underwent surgery.

What it means:

The rate of lung cancer is in the expected range (about one percent). They recruited the right risk population. With usual inclusion criteria, this is what is to expect. Good. No signs of “contamination” with low-risk participants.
The rate of surgery is is high: 54% got surgery, the vast majority in stage I/II, where high cure rates can be expected. Very good.
Stage I/II was 47% – this is much higher than what we see in countries without screening like Germany (23%), but lower than what we saw in other screening trials and programs: NLST 57%, HANSE first round 64%, UK pilots 81%. Why?

So let’s focus on the stage distribution. It depends on various factors:

Real-world vs. study: Real-world inclusion of (maybe mildly) symptomativ patients in the screening group. In a study, these people are usually excluded from screening, which is not feasible in real-world. So people with health concerns due to mild symptoms like cough may be more motivated to go to screening. This may explain part of the difference to the HANSE study (35% stage IV in Croatia vs. 19% stage IV in HANSE). This effect is known in some US programs, when screening is free and diagnostic CT comes with deductibles.
First round vs. consecutive rounds: The Croatian data is mainly first-round scans, where you pick up all pre-existing tumors in the population. From second round on, the stage distribution becomes much better, as you only see newly developed cancers. This is an advantage of the longer-running UK pilots, and the NLST with three rounds. Croatian data is 3/4 first round CT, NLST 1/3 (evenly distributed on three rounds).
Differences in healthcare systems: Also outside screening, we see different stage distributions in different countries – this reflects access to care situation, but also cultural attitudes (health consciousness). If the stage distribution in the population is different, this will show up in screening.

As a conclusion, the Croatian screening program is a big success – the majority of patients got surgery, a large part likely with curative intent. The stage distribution will improve over time automatically, when more consecutive CT scans are evaluated.

Just as a side-note: A high rate of stage IV cancers in a screening program is not really a quality indicator of the screening program – it’s more an indicator of the healthcare system and the overall environment.”

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