nos-trum. pronunciation: \nos'-trum\. noun. Etymology: Latin, neuter of noster our, ours.
1. a medicine of secret composition recommended by its preparer but usually without scientific proof of its effectiveness.
2. a usually questionable remedy or scheme.
See here for more discussion.

Wednesday, July 21, 2010

Diagnosing Cancer: Often Not A Simple Yes Or No

 
If pathology specimens are impossible to diagnose, does that constitute an "error?"

The NY Times has an article (July 19) about misdiagnosis of breast cancer.  The patient described in the article underwent biopsy of a suspicious breast mass.  The pathologic diagnosis was an early stage of breast cancer.  She underwent surgery to remove the mass (note:  this was not a breast removal, only the main lump), radiation, and chemotherapy.  Only to find out that more extensive evaluation of the mass removed failed to identify the early cancer seen on the biopsy.
As it turns out, diagnosing the earliest stage of breast cancer can be surprisingly difficult, prone to both outright error and case-by-case disagreement over whether a cluster of cells is benign or malignant, according to an examination of breast cancer cases by The New York Times.

Advances in mammography and other imaging technology over the past 30 years have meant that pathologists must render opinions on ever smaller breast lesions, some the size of a few grains of salt. Discerning the difference between some benign lesions and early stage breast cancer is a particularly challenging area of pathology, according to medical records and interviews with doctors and patients.
It's really tragic that this patient had to go through all this, but which would you prefer?  Treated when no cancer, or not treated when there was cancer?  (assuming no cancer and no treatment was not an option...we have a breast lump here that competent authority judged to be early cancer initially.)

This makes it sound as though the new technology has brought us to this.  Actually, while the earlier you detect a cancer does make it harder to characterize when the tissue is examined at biopsy, the underlying problem is in the nature of cancer.

When control of cellular growth and division begins to deteriorate, the cells produced can vary along a spectrum of appearance that extends from normal to very chaotic.  Along the way the type of cell becomes less like cells from the original organ, a process that's called de-differentiation

In normal tissue it's not hard to look under the microscope and tell a pancreas cell from a brain cell, from a breast cell.  But as each of these types begin to turn cancerous, in the process of proliferating, they sometimes lose their distinguishing features.

You might guess that the more disorganized and de-differentiated a cell line becomes, the more likely it is to be an aggressive malignancy.  To some extent that's true, but not always.

Pathologists sometimes use dyes, stains, and radioactive markers to identify cell types in addition to appearance, but once again there is variability in response.

Given all the above, the diagnosis is sometimes not clear, or there may be misleading findings.

Several years ago I had a lesion on my arm excised by the dermatologist.  I found out a couple of months later that it had been looked at by my pathologists, sent to other pathologists for other opinions, and finally sent to the Armed Forces Institute of Pathology in DC (at the time, they were the international authority).  The process had taken all of the two months.  In the meantime I had no diagnosis.  I thought, "Wow, it must be bad."  Actually they were trying to decide whether some atypical features meant anything.  They eventually decided it didn't.   Lucky for me.  It healed up and no problems since.

Take a look at my previous post on cancer behavior, and the decision to treat or not, here, for further evidence of indeterminacy.

All cancer is not cancer, and if our knowledge was perfect, not all cancer would need to be treated.  For now we need to err--if error there be--on the side of safety.

Doc D
 
 

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