Blog | Monday, May 18, 2015

Are CT scans accurate for diagnosing cancer?

A female patient came to see me with some difficulty swallowing, a very routine issue for a gastroenterologist. I performed a scope examination of her esophagus and confronted a huge cancer occupying the lower portion of her esophagus.

I expected a benign explanation for her swallowing issue. She was relatively young and not particularly ill. She had seen my partner years in the past for a similar complaint, which he effectively treated by stretching her esophagus. I expected that I my procedure would be a re-run. I was wrong.

Prior to the procedure, we chatted and I learned that she had recently undergone a CT scan of the chest ordered in response to some respiratory symptoms, which were not severe. After I had completed my scope examination of her, I was amazed that no mention of this tumor was related to the patient, who had told me that only a hiatal hernia was seen.

I requested a fax of the report which confirmed that the radiologist made no mention of an esophageal abnormality. I assumed that this scan was not interpreted properly by the radiologist who somehow missed this large, consequential mass in the esophagus. Fortunately, this error caused no harm as I found the cancer just 2 weeks later.

I called the senior radiologist at the hospital as I wanted him to review the scan and to implement whatever internal quality control procedures that existed. I would want the same effort expended if I had missed a lesion or committed a medical error. He reviewed the scan he agreed with the original radiologist's interpretation. He explained to me how in this case the tumor appeared just like a benign hiatal hernia. If any reader is suspected that this guy is just covering for her colleague, I verify that this is not the case. The radiologist I called is irreproachable.

Usually, we face the opposite scenario from radiologist. They find lesions everywhere that are benign, but send patients and their doctors on cascade into chaos.

I believe that the cancer, which developed in such a stealth fashion in my patient, also hid from the radiologist.

My point here for patients is that scans are imperfect. They can miss stuff that matters and uncover stuff that means nothing, the more common outcome. It's a reminder that the practice of medicine is imperfect and offers no guarantees even when it is performed well. This vignette reminds me how important it is to listen carefully to the patient. The scans, labs and even the colonoscopies might be wrong.

If I'm worried about a patient, but the data all scream that he is healthy, should I relax? If a patient feels superb, but the scan shows something found by accident, do I sharpen up the scalpel?

I am gastroenterologist. I prefer to go with my gut.

This post by Michael Kirsch, MD, FACP, appeared at MD Whistleblower. Dr. Kirsch is a full time practicing physician and writer who addresses the joys and challenges of medical practice, including controversies in the doctor-patient relationship, medical ethics and measuring medical quality. When he's not writing, he's performing colonoscopies.