Retrospective: My Zebra

I am in a bad temper today, having just heard that my insurance company has refused to approve my upcoming PET scan, apparently in the belief that it was requested merely for monitoring purposes rather than evaluation for progression and ongoing treatment response. Having a PET or CT scan every three months is entirely standard for mesothelioma, so I don't know what they think they're doing and why they think they know better than my oncologist. However, it may be that they got an abbreviated version of the justification through the radiology practice, so I gave them my oncologist's number and hopefully that will get it straightened out. Hopefully.

This frustrating situation is topical today, as I had already been planning to do a retrospective post on some things that went wrong for me in the medical system in the lead-up to my diagnosis.

I'm told that medical students are trained on the zebra principle: if you hear hoofbeats outside, it is more likely to be a horse than a zebra. So they are encouraged as diagnosticians to think about horses, not zebras. In other words, they are taught to think in terms of statistical likelihoods. The more common illness will be the correct diagnosis most of the time. Horses, not zebras.

The problem comes in if you actually have a zebra, as I do. Arguably, I have something even less statistically likely than a regular zebra: an albino zebra, one might say. A fifty-something-year-old woman with no occupational exposure to the asbestos industry is not expected to get mesothelioma. Statistically speaking, her symptoms will be due to almost anything else. 

An unlikely zebra (image from Wikipedia)

For all that, there were symptoms that were missed or misinterpreted as I made my rounds of doctors last year seeking answers. I have since heard of others in whom similar symptoms were also overlooked or minimized. So I'm making a list here in the hope of being helpful to other zebra sufferers. (The list should be read with the caveat that these are my personal conclusions and I am in no way a medical professional of any kind.)

1. Unintended weight loss. This is the classic sign of cancer, but both I and the doctors thought that the struggle I was having with nausea (see #2) accounted for it. In retrospect, we should all have been more suspicious.
2. Gastrointestinal trouble. The gastroenterologist said she thought I had irritable bowel syndrome. It annoyed me at that time, because IBS should be a diagnosis of exclusion—in other words, it's only a conclusion you arrive at when other possibilities are ruled out. In retrospect, with a cancer diagnosis, I am even more annoyed. It turns out that cancer tends to cause dysbiosis, even when the cancer is not itself in the GI tract. I did get an abdominal CT scan, a fibroscan (a test of the liver), and endoscopy of the pancreas, duodenum and bile ducts, but as it turned out, that was not where the tumors were.
3. Pain in the right-hand side of the abdomen. This pain, which is what finally drove me to the emergency room, was dismissed as "constipation." It turns out that tumors of the lung or pleura (the lung lining, where pleural mesothelioma hangs out) are known to cause right-sided abdominal pain. The pain was incessant for three months but cleared up a week after my first dose of chemotherapy.
4. Pain between the ribs. This was dismissed as costochondritis. 
5. Pain when taking a deep breath. I mentioned this to my regular doctor, and she sent me to get a chest x-ray. Many cases of mesothelioma do get diagnosed from a chest x-ray, but that is only because the x-ray picks up fluid that the cancer is producing. Mine did not start producing fluid until January, just after my diagnosis. So the chest x-ray was clear.

What would have found the cancer earlier? A CT scan of the chest area would surely have done it, but the imaging I had had of the chest was not CT (it was an x-ray) and the CT that I had had was not of the chest (it was of the abdomen). Eventually a second CT with contrast of my abdomen did show pleural thickening at the base of my lung and a mass next to my esophagus. The first CT six months before did not show these, implying that the cancer was growing very quickly. However, I can't help but think that including the thoracic area in the CT scan would have picked up the cancer much earlier.

That said, most people don't have zebras, albino or not. CT scans are not only expensive, but they expose the patient to radiation. If patients were routinely given whole-body CT scans, more cancers would be detected; but some patients would get cancer as a result. It is all the more important to believe in horses rather than zebras if looking for zebras causes cancer. 

If you think you have a zebra, though, advocate for good diagnostics. Be aware that pain can be referred from one part of the body to another one, so a negative scan of the painful area may not be decisive.

If you do have a zebra, good luck to you!