The similarity between the structure and function of the breast and prostate has been known for a long time, but there are serious discrepancies in the terminology describing breast and prostate cancers. The current breast cancer terminology could be improved by modeling it after the method of classifying prostate cancer to reflect the anatomic site of breast cancer origin and the patient outcome. This simple and easily communicable terminology could lead to better communication between the diagnostic and therapeutic team members and result in more rational treatment planning for the benefit of their patients. (Dr. Tabar et al)

A new proposal to unify the terminology for breast and prostate cancers was described in the Breast Cancer: Basic and Clinical Research paper “Unified Classification of Breast and Prostate Cancers.” Dr Laszlo Tabar discusses the background and findings of his research:

How did you become interested in comparing the classification of breast and prostate cancers?

Medical students are told that breast and prostate are histologically similar, but detailed comparison are not given. The epidemiological similarities between breast can prostate cancer woke our interest in making histopathological comparisons using the large-format  subgross, three dimensional histology technique, that has been so revealing of breast cancer structure and greatly furthered our understanding of breast cancer pathophysiology. In both of these organs the cancers originate in either the major ducts or in the fluid-producing part orgenelles. In the prostate the cancers originating form the ductal “ductal adenocarcinoma of the prostate” (DAP) and those originating from the fluid-producing part are called acinar adenocarcinoma of the prostate (AAP). Our studies using 3D histopathology confirmed that this nomenclature is indeed correct and furthermore, the cancers originating from the major ducts had the much poorer long-term outcome.

Unfortunately, the terminology of breast cancer does not follow the logical terminology used for prostate carcinoma. Using the subgross, 3-D histopathology it has become quite clear to us that many of the breast cancer subtypes called “ductal” carcinoma have originated from the acini/lobules. In addition, those breast cancers which have actually originated from the major ducts have a far poorer prognosis than the majority of the breast cancers that have originated form the acini/lobules, even though many of them are traditionally called “ductal carcinoma”. This confusion in terminology makes it much more difficult to accurately predict the prognosis of breast cancer patients. One attempt to overcome this confusion has been to include the so-called second generation prognostic factors, an approach which has not been needed to predict the outcome of prostate cancer cases. We maintain that it is much more logical to redefine the nomenclature of breast cancer according to the site of origin in order to improve our ability to predict the long-term outcome of breast cancer.

What was previously known about the terminology used to describe breast and prostate cancers?  How has your work in this area advanced understanding of it?

Thick section / 3-D histology analysis of in situ breast cancers show that only a minority of these originate from the major ducts and the majority originate from the lubules/acini, although they are mistakenly called “ductal carcinoma in situ” (DCIS). On the other hand, those breast cancer subtypes that truly originate from the major ducts according to 3D histology have a much poorer prognosis and are sometimes also found within metastatic axillary nodes. At 3D histopathology, they can be seen as large tumor-forming conglomerates composed of newly formed ducts. Giving the same name to two vastly different kinds of breast cancer causes confusion, particularly among non-pathologists. We realized that changing the terminology to reflect the site of origin of breast cancer (ductal adenocarcinoma of the breast, DAB versus acinar adenocarcinoma of the breast, AAB) would eliminate much of the uncertainty about breast cancer prognosis.

What do regard as being the most important aspect of the results of your research?

The ability to reliably differentiate the breast cancers of poor prognosis from those of relatively good prognosis, because this should enable much better targeting of therapy.

What was the greatest difficulty you encountered in conducting this studying?

The current TNM classification system was created before the advent of early detection of breast cancer on a large scale. The deficiencies of this system come to light when it is used to predict the outcome of patients with early phases of breast cancer. However, few physicians have any interest in changing this outdated system.

To learn more about Dr Tabar and his research please visit his website Mammography Education Inc

share on