John Bream, MD
Fouunder, Bream Medical
Spoiler alert: I will give the technical explanation for my rationale below, but for those who are just interested a summary and not a highly technical explanation:
My opinion is routine cancer screening is a worthwhile endeavor despite the findings of the below study suggesting routine cancer screening does not prolong life expectancy. The findings in the study are accurate, and I agree with them. However, the issue is that the statistics associated with mass screening do not allow for major changes in generalized data such as life expectancy. However, given the importance on an individual basis of finding detectable cancers in early stages, screening remains a worthwhile endeavor.
A recent analysis suggesting that many routine cancer screens do not prolong life expectancy has garnered significant recent headlines and attention.
And it certainly should! If we are spending billions of dollars on interventions that aren’t helping us to live longer, with Americans racking up significant medical debt, and healthcare accounting for about 18% of GDP, why should we continue doing them?
The answer is…it’s complicated.
Fundamentally, I agree with the conclusions of the article. When we take into account the entirety of the population, routine cancer screenings are not going to prolong life expectancy. The reasons for this are multiple.
- Cancer is generally later life diagnosis. Let’s say we find colon cancer in a 65-year-old male patient. If the patient ends up dying at 68, and the average life expectancy is 76, this is eight years of life missed. However, if we were to contrast this with some sort of intervention that were affecting people who are 25, then this would be 51 life years missed. So, it becomes an issue of simple math that for a lot of cancers, which are diagnosed in older adults, there is not as much life expectancy left, and it would take a lot more positive cases to create improvement in life expectancy – as opposed to an intervention in younger people that have a lot more life expectancy in front of them. In short, it’s hard to move life expectancy based on tests that are usually positive toward when life expectancy is almost competed.
- Most screenings come back to normal. For intervention to significantly increase life expectancy, it would generally need to have a lot of results. Inherently, screenings have what we call high negative pretest probability, which means we expect them to be normal. And thankfully, the majority of cancer screenings are normal. Recent studies have suggested that 78.9% of colonoscopies are normal, 10% had benign polyps, and 12% had cancer. If the screening colonoscopy were to have a higher rate of abnormalities, then the ability to increase life expectancy would be much greater. However, given that most cancer screenings are normal, the mathematics of increasing life expectancy are just not there, fundamentally due to high negative pretest probability.
- Further on the fundamental statistics, most people are only going to have 3 to 4 colonoscopies in their lifetime, approximately 8 to 10 Pap smears, and maybe 20 to 30 mammograms. Statistically, there’s just not much opportunity for interventions that are performed infrequently to produce a large cumulative effect on life expectancy. However, common every day things we do, such as wash hands and wear seatbelts do improve life expectancy because we do them so frequently and start doing them at a very young age.
- While the results of this study are factually accurate due to the mathematical limitations listed above, the results do not change anything about my practice of medicine. My clinic has recently diagnosed a 34-year -old with breast cancer, I had a close colleague in her young 40s who was diagnosed with cervical cancer, and my 67 year old father-in-law was recently diagnosed with colon cancer. Screening tests will significantly prolong their lives – but won’t change anything about generalized population life expectancy. Cancer screenings are about finding and treating cancer in individuals while it is in early stage. Individual results aren’t going to move the needle regarding life expectancy, but I guarantee you that all of them will tell you that the screenings were worth it.
So, in summary, while the overall population is not going to live longer in aggregate as a result of cancer screening, the ability to prolong the life of someone with a positive screening by providing them early detection and intervention makes routine screening worthwhile.
Bream Medical is an all-inclusive, non-corporate practice that provides urgent care, primary care, and direct primary care services in Salisbury, Edenton, and Stokesdale, NC, and provides telemedicine consultation anywhere in North Carolina. We provide excellent healthcare by prioritizing patients care – not profits. To learn more about Bream Medical, visit https://breammedical.com or call 336.560.6033 (Stokesdale), 704.216.1263 (Salisbury), or 252.482.3350 (Edenton).