22 pack-years but I quit 16 years ago. Do I still count for the lung CT or have I aged out of it?

I have spent a genuinely embarrassing amount of this week doing arithmetic about cigarettes I smoked in the nineties.

Context: I'm 54. Twenty a day from 19 until I stopped at 38, which by my sums is about 22 pack-years if I'm honest about the years I was on more than a pack. I quit sixteen years ago this November. A friend at work has just been invited onto a lung screening programme and it has put the idea in my head for the first time, so I looked up the criteria and got smacked in the face by the fifteen year rule. Quit within fifteen years, you're in. Sixteen, apparently you're out.

Which feels absurd? My lungs did not celebrate the anniversary and reset. I understand a line has to go somewhere, I just don't understand why THAT line, and whether missing it by eleven months means "you're fine now" or means "you're on your own now". Those are extremely different messages.

Related question for anyone who's been through it: my clinic will sell me a low-dose CT privately without any of this. Do I just buy one and stop thinking about it? Bearing in mind I am the person on this board who bought a full-body MRI and got five months of homework out of it, so I know what I sound like.

Ha, the "my lungs did not celebrate the anniversary" line is exactly right and also exactly the problem with every threshold in screening. Age 50, 20 pack-years, 15 years since quitting, they are all lines drawn through a smooth slope because you cannot run a programme on vibes.

I'm the other side of it, I stopped at 27 and never got near 20 pack-years, so I'm nowhere near eligible and have made my peace with that. But I'd push back gently on the buy-it-privately plan, and you already know why: you have personally posted the receipts for what happens when a detailed scan looks at a healthy person. A chest CT finds nodules in a big chunk of everyone. Then you're in the follow-up scan cycle, at your own expense, with nobody having decided in advance what would count as an answer.

gregor_runs said:

you have personally posted the receipts

Fair. Filed under "advice I'd give anyone else".

My father in law is on a programme like the one your colleague got invited to and the thing that surprised me is how much of it is NOT the scan. He got a proper sit down first where someone went through his history with him and worked out his actual risk score, not just pack-years, and then a long conversation about the fact that a scan finds things and here is what happens next if it does. Then the scan. Then he gets recalled every year.

Second scan found a 5mm nodule. They didn't biopsy anything, they just rescanned him at three months to see if it had changed. It hadn't. He's back on the annual cycle. Whole thing was calm in a way I did not expect, and I think that's because the follow-up plan existed before the finding did.

That's the difference I'd worry about with buying one off a menu. Not the scan, the scaffolding.

Fi, the short answer to your direct question: on the most widely used criteria you have missed eligibility, and it genuinely is not the insult it feels like. But the fuller answer is that the criteria are not universal, so "am I eligible" depends on where you are.

The rule you found, roughly ages 50 to 80, about 20 pack-years, currently smoking or quit within 15 years, is one influential formulation. Several national programmes have moved away from fixed pack-year cut-offs entirely and use a risk-prediction model instead, which folds in age, smoking pattern, family history, and other factors, and picks people above a calculated risk threshold. Someone with your history and one or two other risk factors can be included by that route and excluded by the pack-year route on the same day. So the useful question is not "do I qualify" in the abstract but "how does the programme available to me decide", which is a question for your own clinician with your notes in front of them.

Why the 15 years exists: risk after quitting falls, slowly and continuously, and at some distance from quitting the expected benefit no longer clearly outweighs the harms of scanning, which are cumulative radiation, false positives, and overdiagnosis. It is a judgement about where that crossover sits on average, and averages do not describe you specifically. Nobody thinks your risk changed overnight.

On the private scan, I will not tell you what to buy, but I would ask the clinic three things before you do: who reads the images and against which reporting standard, what exactly happens if a nodule is found and who pays for the follow-up, and whether they will still be doing this scan annually for the next decade, because a single scan is not what the evidence supports. The site's rundown of lung cancer screening and who low-dose CT is for sets out the eligibility logic and the nodule follow-up pathway in more detail than a booking page will.

One more thing, said plainly because it is the part that matters most: nothing on a scanner reduces risk. Not smoking does, and you already did that sixteen years ago. That decision has done more for your lungs than any imaging will.

The "who pays for the follow-up" question is the one I'd hammer on. When I did my package the add-on price covered the scan and precisely nothing downstream, which nobody volunteers until you ask.

Update. Took it to my GP rather than the clinic, which I'd never have done a year ago.

Verdict was roughly what Aaron said. Under the criteria our local programme uses I'm outside it, but she went through the risk factors properly rather than just the pack-year sum, and said if the programme here shifts to a risk-based model I'd be worth reassessing, so she's noted it. She was not enthusiastic about the private CT and her phrasing has stuck with me: buying a scan without a plan for what a finding means is buying the first half of something.

So: not screened, mildly annoyed about eleven months, and no longer planning to spend four figures to be annoyed differently. I did ask about the cough I've had since spring, which turned out to be the more useful question in the room and is being looked at properly. Funny how that works.