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Consider the following hypothetical case: Mary is a woman who has no ovarian cancer symptoms and is not known to have a high-risk cancer syndrome. She nevertheless gets a transvaginal ultrasound and discovers that she has a growth on one of her Ovaries. She then gets a ROMA (Risk of Ovarian Malignancy Algorithm) test done which places her in the high-risk category. Should she get the ovary taken out? It seems plausible that this would at least be a reasonable option that should be considered with the help of expert medical advice.

On the other hand, all medical authorities have come out against ovarian cancer screening. The US Preventative Services Task Force (USPSTF), for example, has found that screening does not reduce ovarian cancer mortality and can result in important harms such as many false positive results which may result in unnecessary surgery. They assert that the harms outweigh the benefits and recommend against it.

To me this recommendation entails that Mary should definitely not take further action, even though she knows she is in the ROMA high risk category. I am assuming the risks of actually having an ultrasound and the ROMA test are negligible. I also assume that Mary should take action only when the harms of that action do not outweigh its benefits (taking into account the likelihood of these harms and benefits).

It might be objected that the USPSTF recommendation only applies to women who have not taken any test – Mary has had positive results from the ultrasound and ROMA test and that removes her from the category of women to whom the recommendation applies. Everything that she does after the ultrasound is not part of screening.

But women who were screened during the surveys that were used to evaluate the effectiveness of that screening didn’t just get screened – they went on and had further tests and treatment if they had positive results and results of these actions formed the basis of the anti-screening recommendation. The harms and lack of benefits of screening are not caused by the screening itself – it is the actions that are taken on the basis of positive results that cause them. So the fact that Mary has had the screening itself shouldn’t make any difference and neither should the ROMA since its risk of harm is negligible.

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This is actually answered in my response to your previous question, but it is a good concept that can take some work to wrap one's head around, so I will go in more depth.

Please note that no one other than the individual's physician can advise on what next steps to take once a positive finding is identified - regardless if the positive result was found incidentally or not.

This answer is about the fundamental concepts of screening vs diagnostic testing and incidentaloma management.

Screening vs diagnostic

For the most part, a medical test is a medical test. There are only a few tests that only have application in a screening setting - most are just a test to look for something specific. For example, the PSA blood test just gives the serum concentration of prostate-specific antigen, and can be used for both screening and diagnostic purposes.

A test is defined as being "screening" when it is applied to an asymptomatic individual to search for signs of disease development prior to onset of clinical symptoms, in the hopes of catching disease early.

A test is defined as being "diagnostic" when it is applied (1) in the diagnostic process of a symptomatic individual - or just in general when used for monitoring progress, response to treatment, etc.

In public health and population health, the principles of primary prevention, secondary prevention, and tertiary prevention are related to those definitions. http://www.med.uottawa.ca/courses/epi6181/course_outline/Concepts-prev.htm Screening tests are one of the most important tools to improve the health of a population, and the considerations for whether to apply a test to everyone within that population depends on that benefits vs harms balance previously discussed. The USPSTF, CDC, and academies like ACOG AAFP AAP AHA etc etc review the research and make recommendations on whether a screening test should be given to everyone in the population capable of developing the disease or not. It is not always simple, the agencies don't always agree, and ultimately it is up to the individual and their physician to make an educated decision for that individual's situation. Physicians are trained in these discussions and decision making processes within their scope of care.

Incidental findings

I think that what you are referring to is an incidental finding of a mass on a test that was done for another reason. This is commonly referred to as an "incidentaloma" in the medical field, and there are also detailed guidelines on management of incidental masses depending on the type. For example, transvaginal ultrasounds done as a diagnostic test for abnormal uterine bleeding can *incidentally *find an ovarian mass that was previously unknown and asymptomatic. In fact, many transvaginal ultrasounds find incidental cystic masses with a stereotypical appearance that are 100% normal ovarian cysts; however, depending on the features of the mass (or a risk factor of the individual) then additional testing may be indicated.

In that case, the ordering physician (or a specialist they refer the patient to) will go over a risk assessment process - often following an algorithm specific to the mass type - that adds more data to the picture. This process usually includes additional history (like family members with related cancers, smoking etc, job exposures, etc) and/or additional exams and tests (like ROMA), and provides additional information to guide the patient and provider in how much that **INDIVIDUAL is at risk** of the incidental mass actually being cancerous.

Note that some incidental masses won't need additional testing because something about its site/organ/appearance either is (1) so high risk just by existing that they go straight to biopsy or even surgical removal, or (2) so low risk that they rarely/never are harmful so they are just monitored or ignored.

This individual risk assessment is quite different than asymptomatic screening for secondary prevention at a population level. Once a mass is identified, the term "screening" is thrown out the window. Along with the term screening, the concepts of harm/benefit of testing change as well, now that the cat's out of the bag, we've got a positive finding and now we have to decide what is best for this individual based on individual factors.

Additional notes

This concept is exactly why medical professionals usually caution against ordering testing that does not specifically answer a question related to a recommended screening test, presenting clinical symptom, or existing disease. Otherwise, if an abnormal result is found in an asymptomatic otherwise healthy individual, now we're left with the questions: what do we do about this now that we know? What would have happened if we had never noticed it? Is there more potential for bad outcomes if we do more testing, or if we just watch and wait? The answers differ by finding and by individual, so I refer back to my statement:

No one other than the individual's physician can advise on what next steps to take once a positive finding is identified - regardless if the positive result was found incidentally or not.

References

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  • Please offer me feedback on this explanation, as it's sometimes hard to articulate these concepts in plain language, and I'd like to be able to get the point across without the public health terminology! – DoctorWhom Sep 23 '19 at 21:35
  • I think I understand what you are saying but I don't see how it addresses my concern. In my hypothetical example the positive result is not incidental since it came from a screening test, not a diagnostic for a different problem. I know everyone is a unique individual but , by hypothesis, Mary possesses the characteristics that make the anti-screening recommendation apply to her. I'm not asking whether she should take further action, I am asking whether she should take further action if the anti-screening recommendation is correct. – Richard Sep 24 '19 at 17:19
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    @Richard I think DoctorWhom's answer makes it clear (well, as clear as is possible) that in that case it comes down to an individual risk assessment, which may or may not be concordant with a population-wide risk assessment. – Bryan Krause Sep 24 '19 at 18:52
  • @BryanKrause I am not convinced. Lets say Mary visits her specialist who recommends surgery. It follows that the specialist has correctly included Mary in a category of indivduals who have been shown to benefit from (taking into account risk etc) surgery when they have a positive screening result etc. Now this must be based on research that presumably the USPSTF should know about. Should the USPSTF not exclude women in this category from its recommendation? Either this category exists and the USPSTF recommendation is wrong or it doesn't exist and then Mary should take no further action. – Richard Sep 26 '19 at 14:13
  • @Richard The USPSTF guidelines already exclude people with symptoms or at higher risk. The guidelines are not updated constantly, new research can always identify new risk groups, and it's not possible for broad guidelines to be tailored to every individual circumstance. – Bryan Krause Sep 26 '19 at 14:32

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