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Speed of Tumor Growth

Speed of Tumor Growth

Question
Dear OncoLink "Ask the Experts,"
I found out two weeks ago that my father is suffering from incurable cancer. The cancer is classified as poorly differentiated carcinoma. I am told that it is very aggressive. It was first found in the lung and kidney area. It has since been discovered in the brain.

I have found your information to be very helpful. But, I need a little more help The issue is this: It is believed that the first clinical sign of the cancer was in March of 1997 (confirmed by Chest X- Ray). On the Aug 1, 1997 it was determined that cancer had spread (metastasized) to at least 3 areas. Can you tell me about the speed at which cancer spreads?

I really appreciate your understanding and am thanking you in advance for any assistance you can provide.  
Thanks.
ES


Answer
Kenneth Blank, MD, OncoLink Editorial Assistant, responds:

Dear ES:
Every cancer is different with respect to the speed with which it grows and spreads. In fact, cancers may change their growth rates. For example, a slow growing tumor may "take off" and begin to grow and spread rapidly.

However, some generalities can be made which relate to the "histology" and "differentiation" of the cancer. The differentiation of a tumor refers to how the cells look under the microscope. Cells that look normal are termed well differentiated. On the other hand, if the cells appear very abnormal they are termed poorly differentiated. Poorly differentiated cancers, like your father's, tend to grow quicker than well differentiated tumors, and moderately differentiated tumors fall in between.

The histology of a cancer relates to the pattern the cells form as whole when viewed under the microscope. This also influences a tumor's rate of growth and spread. Two different histologic types of lung cancer illustrate this point. Small-cell lung cancers tend to grow and spread very rapidly. In contrast, non-small cell lung cancer tends to grow and spread at a slower rate.

The best test to determine the rate of growth and spread of any cancer is to study the course of the patient under question. A patient who had a normal chest x-ray one month, and two months later has a large lung cancer obviously has a rapidly growing tumor. The 'test of time,' unfortunately, is often the only way to truly discover the nature of an individual cancer.