a) it was published yesterday, which means there is insufficient time to have a good critical appraisal.
b) looking at the confidence intervals, although there is significance in men, there is not one in men, and the confidence interval is quite wide
c) all cause mortality is similar in both groups despite screening
d) the follow up is only 10 years after first CT. the effect of radiation from these multiple CTs is unlikely to have reached maximum effect in damage to tissues/new neoplasms. This may also explain the increased non lung cancer mortality.
e) no mention is made of morbidity (although I might have missed it) which is a huge importance.
Overall, it’s unsurprising that in a group screened regularly for lung cancer that lung cancer incidence increases but mortality drops. The problem is the other effects of screening which this paper doesn’t seem to focus on. I don’t think this actually shows screening is particularly worth it especially given it’s caveats.
I am by no means a lung cancer expert, but currently there is contention about whether lung cancer screening in smokers is worthwhile, and I doubt at 6 monthly intervals. Some studies have shown benefits from screening for smokers, but I dont think any high quality evidence exist which shows a clear benefit of screening. There are options for screening, chest xray, CT chest. A CT chest is more sensitive than a chest xray but doing it every 6 months is going to cause much more harm than good.
My more general point is that these are recommendations which need to be evidence based, and doing more harm than good through false positives, excess radiation exposure, etc is a real risk. I dont think its helpful to make suggestions that are not based on evidence.