Why we are diagnosing disease too late

It is well understood that a late diagnosis of a serious health condition often leads to a much worse outcome.

This can be best understood in the context of cancer. During our lifetimes all of us have just over a 50% chance of being diagnosed with cancer. And yet despite the visibility and awareness that we have about cancer, almost half of those diagnoses happen when the patient reports to the hospital with acute symptoms of advanced cancer.

Cancer is diagnosed, on average, in late stage II around the time that it begins to spread to surrounding lymph nodes and other organs. The cost of this late diagnosis is significant. The odds of survival, which can differ greatly by the type of cancer, can be 4-7x higher for cancers that are diagnosed in stage I rather than in stage II.

So why is it so hard to diagnose cancer and other diseases early? Here are four reasons why this still happens.


Lack of screening tests or poor accuracy

The ugly reality of modern medicine is that, when it comes to preventative health or early diagnosis, there is very little available to the average front-line doctor. This greatly impacts the ability to diagnose disease when it can be successfully treated.

With cancer as an example; there are really only three common cancer screening programs in North America - mammography for breast cancer, PSA blood test for prostate cancer and colonoscopy for colon cancer. Each has their own issues: patients don't like doing a colonoscopy even though it is a highly sensitive test, mammography struggles to see through dense breasts and has a relatively high false positive rate, and PSA levels in men can vary for many reasons unrelated to prostate cancer.

Many other conditions such as aneurysms, dementia, stroke risk, IBD, colitis, kidney stones and so on do not have effective screening tests.

We aren't very good patients

Even when symptoms are present, we are not always the best at following up on them. There are lots of underlying reasons why we do not check in with the doctor regularly.

We trivialize symptoms rather than entertain the thought that it could be something serious.

We don't want to be seen as "the sort of person who goes running to the doctor" whenever anything feels out of the ordinary.

We don’t want to be told that the symptom is just a normal thing that does not require treatment.

Or it might just be difficult to visit a doctor due to location, availability of doctors, or that we don't want to sit in a waiting room of a walk-in clinic for hours on end.


Many serious diseases lack symptoms until advanced

If you ask most physicians if pancreatic cancer is a terminal cancer they will say "yes". But the reality is that it is deadly because it is generally detected in a very late stage. Pancreatic cancer is caught late because there are rarely early symptoms. Almost all cancers that you can't see or feel, tend to cause specific symptoms only in the late stages of the disease.

Many other major diseases tend to have delayed symptoms. This might be due to the fact that our bodies have built in "plasticity" allowing an organ can become quite diseased before function is severely impaired. A small number of fatal conditions, like brain aneurysms, very rarely give any warning at all before they become deadly. There are some conditions which can give conflicting signals. For example, liver cancer can present as a pain in the shoulder and kidney cancer can present as back pain.

Doctors have trouble being a good backstop

Doctors have to make pragmatic decisions when a patient presents with symptoms. For example, in the abdomen there are thousands of medical conditions that share hundreds of common symptoms.

Many times, it makes sense to go with the most common diagnosis. For example, ongoing abdominal pain in a 30 year old is more likely to be Irritable Bowel Syndrome (IBS) than colon cancer. So the doctor is more likely to diagnose IBS.

Due to cost pressures in the health system, doctors may be discouraged from investigating low probability diagnoses, even if they have serious consequences for the patient.