# Why no mandatory xrays? **URL:** \ **Category:** Factual Questions\ **Created:** [March 26, 2010, 3:28pm UTC](https://boards.straightdope.com/t/why-no-mandatory-xrays/533886 "2010-03-26T15:28:00Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![HorseloverFat](https://avatars.discourse-cdn.com/v4/letter/h/8e8cbc/32.png) [@HorseloverFat](https://boards.straightdope.com/u/HorseloverFat)\ **Post date:** [March 26, 2010, 3:28pm UTC](https://boards.straightdope.com/t/why-no-mandatory-xrays/533886/1 "2010-03-26T15:28:00Z")
I was watching an old British movie where the main character was going to a routine chest xray. Ive seen this scene before in movies where a patient has some kind of mandatory scan and there’s a long line of people at the doctor’s office waiting for their xrays too. From the context none of these people think they are sick. They are just going in for this scan. Was this ever a policy in the US? If not, why not? I know colonoscopies are recommend for people at age 50 but not chest or thoracic xrays. It seems like a good idea. Cancer is difficult to detect without some kind of scan and most cancer stories Ive read about (and know from people IRL) tend to start with “I had a pain and the doctor recommended a CAT scan.” ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [March 26, 2010, 3:41pm UTC](https://boards.straightdope.com/t/why-no-mandatory-xrays/533886/2 "2010-03-26T15:41:06Z")
chest xrays were used to screen for Tuberculosis which was more common before vaccines used now. ---
**Author:** ![kayaker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kayaker/32/441_2.png) [@kayaker](https://boards.straightdope.com/u/kayaker)\ **Post date:** [March 26, 2010, 3:43pm UTC](https://boards.straightdope.com/t/why-no-mandatory-xrays/533886/3 "2010-03-26T15:43:40Z")
> [@johnpost](#): > > chest xrays were used to screen for Tuberculosis which was more common before vaccines used now. Cite? There is a vaccine for TB? ---
**Author:** ![threemae](https://avatars.discourse-cdn.com/v4/letter/t/5f9b8f/32.png) [@threemae](https://boards.straightdope.com/u/threemae)\ **Post date:** [March 26, 2010, 3:46pm UTC](https://boards.straightdope.com/t/why-no-mandatory-xrays/533886/4 "2010-03-26T15:46:26Z")
Because there isn’t any science to support a screening chest x-ray in otherwise healthy, asymptomatic people. A good general screening exam detects disease: 1. significantly earlier than the disease would otherwise be likely to manifest itself with symptoms 2. That you can actually do something about 3. The screening exam should not impose an undue health risk upon the population being screened Also, the value of a screening test is improved it’s good if the test is cheap, the condition has a high prevalence in the population, and if the treatments are cheap and effective. To use the example of colonoscopies, colon cancer is the second most common cause of cancer death in all-comers in the United States, the colonoscopy is both a screening tool and a therapeutic tool (you can use it to pull off polyps likely to develop invasive cells), relatively safe, and relatively cheap. An early-stage cancer discovered by colonoscopy will often be years before it would otherwise become symptomatic, and surgical resection of these early cancers is effective at reducing mortality Basically, a colonscopy can radically alter the course of a serious disease for a lot of people. Consequently, a screening colonoscopy is a very good idea for a lot of people. Here’s the USPSTF’s take on it: > **[Clinical Guidelines and Recommendations](https://www.ahrq.gov/prevention/guidelines/index.html)** > > Evidence-based research provides the basis for sound clinical practice guidelines and recommendations. The database of guidelines available from the National Guideline Clearinghouse and the recommendations of the U.S. Preventive Services Task Force... For lung cancer, few of these things are true. Although it’s a bad cancer with a high prevalence, for many forms the clinical outcomes are not significantly modified by treatment. A CXR presents some risk, mainly that we’ll start biopsying too many benign lesions and the biopsies cause the risk of injuring a lung, blood vessels, etc. Basically, our current science suggests that screening would do more harm than good. Here’s an example of the USSTF’s statement on lung-cancer screening (probably the most important entity related to a “mandatory,” chest x-ray): > **[Clinical Guidelines and Recommendations](https://www.ahrq.gov/prevention/guidelines/index.html)** > > Evidence-based research provides the basis for sound clinical practice guidelines and recommendations. The database of guidelines available from the National Guideline Clearinghouse and the recommendations of the U.S. Preventive Services Task Force... ---
**Author:** ![threemae](https://avatars.discourse-cdn.com/v4/letter/t/5f9b8f/32.png) [@threemae](https://boards.straightdope.com/u/threemae)\ **Post date:** [March 26, 2010, 3:55pm UTC](https://boards.straightdope.com/t/why-no-mandatory-xrays/533886/5 "2010-03-26T15:55:03Z")
> [@kayaker](#): > > Cite? There is a vaccine for TB? Although there is a, “vaccine,” for TB ([BCG vaccine - Wikipedia](http://en.wikipedia.org/wiki/Bacillus_Calmette-Gu%C3%A9rin)) it isn’t a very effective one and it does the least against the most infectious (and from a public-health standpoint most important) forms of the disease. However, TB screening is very important in certain populations (immigrants from certain nations, prisoners, health-care workers, etc.) The language surrounding TB is very confusing for lay-persons because of the convoluted life-cycle of the pathogen, but essentially TB screening and TB treatment guided by that screening permits you to prevent latent infections from becoming active, infectious disease. That said, a CXR is better at demonstrating, “active,” TB when its already too late to completely avoid becoming infectious to others, so we use screening tools such as the PPD (purified protein derivative) to demonstrate which individuals would benefit from drug therapy to head-off the development of active, infectious, TB. That’s how TB screening in certain populations produces an important public health benefit. A statement from the CDC that goes more in-depth on these issues: > **[Targeted Tuberculin Testing and Treatment of Latent Tuberculosis Infection](https://www.cdc.gov/mmwr/preview/mmwrhtml/rr4906a1.htm)** ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [March 26, 2010, 3:55pm UTC](https://boards.straightdope.com/t/why-no-mandatory-xrays/533886/6 "2010-03-26T15:55:59Z")
> [@johnpost](#): > > chest xrays were used to screen for Tuberculosis which was more common before vaccines used now. > [@kayaker](#): > > Cite? There is a vaccine for TB? xray was used in USA and world for screening decades back. current vaccine is used elsewhere in the world. so my statement wasn’t limited to USA as the OP addressed. > **[FAQ about BCG](https://www.priory.com/cmol/bcg.htm)** > > Frequently asked questions about the BCG immunisation - a review article ---
**Author:** ![kayaker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kayaker/32/441_2.png) [@kayaker](https://boards.straightdope.com/u/kayaker)\ **Post date:** [March 26, 2010, 3:59pm UTC](https://boards.straightdope.com/t/why-no-mandatory-xrays/533886/7 "2010-03-26T15:59:09Z")
> [@johnpost](#): > > xray was used in USA and world for screening decades back. current vaccine is used elsewhere in the world. so my statement wasn’t limited to USA as the OP addressed. > > [FAQ about BCG](http://www.priory.com/cmol/bcg.htm) Thanks! I was totally unaware. ---
**Author:** ![Chief\_Pedant](https://avatars.discourse-cdn.com/v4/letter/c/a6a055/32.png) [@Chief\_Pedant](https://boards.straightdope.com/u/Chief_Pedant)\ **Post date:** [March 26, 2010, 4:16pm UTC](https://boards.straightdope.com/t/why-no-mandatory-xrays/533886/8 "2010-03-26T16:16:12Z")
> [@threemae](#): > > Because there isn’t any science to support a screening chest x-ray in otherwise healthy, asymptomatic people. > > A CXR presents some risk, mainly that we’ll start biopsying too many benign lesions and the biopsies cause the risk of injuring a lung, blood vessels, etc. Basically, our current science suggests that screening would do more harm than good. > > Here’s an example of the USSTF’s statement on lung-cancer screening (probably the most important entity related to a “mandatory,” chest x-ray): > [http://www.ahrq.gov/clinic/3rduspstf/lungcancer/lungcanrs.htm](http://www.ahrq.gov/clinic/3rduspstf/lungcancer/lungcanrs.htm) Good post, and I agree with most of it. Technically, I think it’s better to say that the benefit of screening CXRs is undecided rather than harmful. See your cite for the details around CXRs: _“ **Summary of Recommendation** The U.S. Preventive Services Task Force (USPSTF) concludes that the evidence is insufficient to recommend for or against screening asymptomatic persons for lung cancer with either low dose computerized tomography (LDCT), chest x-ray (CXR), sputum cytology, or a combination of these tests.”_ All of the effort that goes into these sorts of screening decisions (mammograms getting the most recent notoriety) revolves around two concepts: 1. Is it good for the patient?, and 2. Is it good for society? An extreme example to demonstrate the point: If you had an absolutely risk-free screening exam that cost $100,000 but saved one life per thousand screenings, the answer to question 1 is “yes.” And if the $100,000 were spare change for me, I’d have it done. However the answer to #2 is “no” because society cannot afford a cost of $100,000,000 to save one life. It turns out answering question 1 is quite difficult and answering question 2 gets quite philosophical, as well as practical. For question 1, all the points you raised are appropriate ones. It turns out with CXRs it’s an extra-tough question because things like its sensitivity and specificity and positive-predictive values vary enormously by population. And for question 2, to get the real cost if you are doing a cost-benefit analysis you have to add it all of the costs of tracking down false-positives as well as subtract from the benefit side all of the complications of any invasive procedures (along with very subtle things like the total radiation from the CXR, a follow-up low-dose CT scan, say, and a follow-up high-dose scan or whatever). To the OP’s question about CXRs in general for lung cancer screening, I’d say we’ll move to a world eventually where non-invasive imaging studies such as total-body MRI become increasingly common. Just my 2 cents, although some [for-profit screening centers](http://www.inviewimaging.com/full-body-scan.htm) are already on the bandwagon. ---
**Author:** ![Honesty](https://avatars.discourse-cdn.com/v4/letter/h/f04885/32.png) [@Honesty](https://boards.straightdope.com/u/Honesty)\ **Post date:** [March 26, 2010, 5:29pm UTC](https://boards.straightdope.com/t/why-no-mandatory-xrays/533886/9 "2010-03-26T17:29:43Z")
> [@HorseloverFat](#): > > I was watching an old British movie where the main character was going to a routine chest xray. Ive seen this scene before in movies where a patient has some kind of mandatory scan and there’s a long line of people at the doctor’s office waiting for their xrays too. From the context none of these people think they are sick. They are just going in for this scan. > > Was this ever a policy in the US? If not, why not? I know colonoscopies are recommend for people at age 50 but not chest or thoracic xrays. > > It seems like a good idea. Cancer is difficult to detect without some kind of scan and most cancer stories Ive read about (and know from people IRL) tend to start with “I had a pain and the doctor recommended a CAT scan.” Well, X-rays cause DNA to form adducts that must be excised using the host DNA repair machinery. If DNA repair fails, and if the adduct was in a tumor suppressor gene, you can develop cancer. You shouldn’t get unnecessary X-rays just like you shouldn’t play catch with a ball of polonium-210. ---
**Author:** ![The\_Second\_Stone](https://avatars.discourse-cdn.com/v4/letter/t/bbe5ce/32.png) [@The\_Second\_Stone](https://boards.straightdope.com/u/The_Second_Stone)\ **Post date:** [March 26, 2010, 6:19pm UTC](https://boards.straightdope.com/t/why-no-mandatory-xrays/533886/10 "2010-03-26T18:19:21Z")
Chest x-rays used to be routine for certain industries in the US. The industries I know about were the ones at risk for lung diseases, such as shipyard workers, refinery workers. ---
**Author:** ![elbows](https://avatars.discourse-cdn.com/v4/letter/e/b3f665/32.png) [@elbows](https://boards.straightdope.com/u/elbows)\ **Post date:** [March 26, 2010, 6:59pm UTC](https://boards.straightdope.com/t/why-no-mandatory-xrays/533886/11 "2010-03-26T18:59:24Z")
I am over 50 and have had a mandatory chest xray, for a service job, about 30 yrs ago now. I think they were looking for signs of TB. ---
**Author:** ![toodlepip](https://avatars.discourse-cdn.com/v4/letter/t/97f17d/32.png) [@toodlepip](https://boards.straightdope.com/u/toodlepip)\ **Post date:** [March 27, 2010, 12:59am UTC](https://boards.straightdope.com/t/why-no-mandatory-xrays/533886/12 "2010-03-27T00:59:50Z")
> [@kayaker](#): > > Cite? There is a vaccine for TB? I had the [BCG vaccine](http://en.wikipedia.org/wiki/Bacillus_Calmette-Gu%C3%A9rin) when I was 14, in Norway. It was a standard part of the routine vaccinations till last year, but is now only given to people considered at risk (children of immigrants from certain parts of the world, health care workers, etc.). The vaccine is considered very safe, and around 80% effective. You get a small lump at the injection site, which usually bursts into a weeping mess after a couple of weeks and leaves a permanent scar when it finally heals. Mine’s maybe 10-12 mm wide. It’s always given in the left arm, so it’s easy to tell if someone’s been vaccinated. I once worked on a research project involving TB in mice. The biosecurity was tedious, to say the least, and our BCG vaccinated mice were well enough protected to die from old age rather than TB, despite considerable efforts to infect them. ---
**Author:** ![DCnDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dcndc/32/2842_2.png) [@DCnDC](https://boards.straightdope.com/u/DCnDC)\ **Post date:** [March 27, 2010, 1:07am UTC](https://boards.straightdope.com/t/why-no-mandatory-xrays/533886/13 "2010-03-27T01:07:52Z")
> [@Honesty](#): > > You shouldn’t get unnecessary X-rays just like you shouldn’t play catch with a ball of polonium-210. Agreed. I tend not to trust machines that the operator has to leave the room to turn on.