The Wrong Diagnosis Means the Wrong Treatment

I have been talking for a long time about how radiologists and pathologists are having more and more trouble deciding whether tiny clumps of suspicious-looking cells in the breast are cancerous or not.

So it did not surprise me when the New York Times reported the other day that, because so many tiny lesions are being misdiagnosed as malignant, more and more women are being mistakenly treated for cancer.

New technology brings new problems

Why all this difficulty with deciding if a little group of cells is cancerous? Blame it in part on the new and improved digital technology: MRI mammograms have sharpened the clarity of breast images so much that we can now see microcalcifications that are, frankly, too tiny to interpret correctly every time.

The troublesome DCIS

Most types of breast cancer are large enough for the pathologist to see clearly, so the increasing numbers of misdiagnoses are not an issue with them. The trouble usually occurs only when a woman has a possible ductal carcinoma in situ (DCIS), which is a tiny clump of noninvasive (stage 0) breast-cancer cells still sequestered inside a duct of the woman's breast.

It has always been difficult to tell atypical ductal cells (which aren't cancerous) from DCISs, and now digital mammograms have made this distinction ever harder to confirm--sometimes even impossible. 

DCISs are maddeningly problematic for another reason: We sometimes won't know for years whether a DCIS is going to grow into a life-threatening cancer. In fact, 70 percent of DCISs will eventually turn out to be completely harmless!

So even though the DCIS is a well-known indicator for increased risk of breast cancer, many DCISs cannot be classified for sure as breast cancers during their very early stages. We just can't always tell at the time of biopsy which "mystery speck" is going to cause trouble.

If you call it cancer, you have to treat it like cancer

This leads to the serious problem discussed in the Times article. Even though fully 70 percent of DCISs turn out to be false positives, surgeons and radiation oncologists are still required to treat each one as potentially deadly--otherwise, these specialists would just be playing Russian roulette.

And so 70 percent of women with an initial diagnosis of DCIS are unnecessarily subjected to the complete array of medical procedures automatically set in motion at the first mention of cancer: biopsy, radiation, and even mastectomy. That's a lot of dangerous, painful, and needless procedures.

Regular tumors can also be misdiagnosed

Even if a tumor is large enough to show up clearly on mammography, there's still many ways a diagnosis can go wrong. Was the surgeon or radiologist performing the biopsy an expert at removing tissue samples from a suspicious site? Were the right tissue samples removed from the appropriate places? Were these samples large enough to allow a clear interpretation? Was the pathologist proficient at diagnosing breast-cancer cells under a microscope? (Most hospitals only have general pathologists, not pathologists who specialize by tumor type. At Hopkins, we do have such specialists, and it's something I consider one of our strengths.)

The power of the pathologist

I've always said that the pathologist holds all the cards because he or she gets to review the pathology slides and write the report that determines the patient's diagnosis and treatment plan. Wow! Powerful people--and yet the patients never get to meet them.

So what is a woman to do?

• From the start, she needs to be in the hands of specialists--a breast-imaging radiologist, for example.
• She must avoid having a general radiologist read her mammograms.
• Her radiologist must also be an expert at performing core biopsies. (This would be a breast-imaging radiologist dedicated to working exclusively in a breast-imaging setting that includes diagnostic evaluation services.)
• She must make sure that another specialist, this time a breast pathologist, reads the pathology slides from the biopsy and makes the most accurate diagnosis possible.
• Last, if the breast center(s) near her home doesn't have such a set-up, then she must send her films and slides to a comprehensive breast center where such experts are plying their trades.

Obviously, accuracy is crucial. What would be ideal is for you to pack up your slides and films and bring yourself along for a second-opinion consultation at a top-notch breast center. Then, once a diagnosis is made, no matter what it is, you can have more confidence that what lies ahead will be the right thing for you to do.