gdpawel
Senior User
Joined: 15 Jan 2005
Posts: 123
Location: Pennsylvania
|
 Posted: Fri Sep 23, 2005 7:24 pm Post subject: Can Chemo be bad even when it's good? |
 |
|
Can chemotherapy ever be bad, in cases where it apparently works? Traditional chemotherapy is mutagenic (changes in form). You might kill off a whole lot of cancer, only to cause a mutation in the remaining cancer, such that the remaining cancer behaves in a more agressive fashion.
As reported at the 27th Annual San Antonio Breast Cancer Symposium, using a technique that quantifies circulating tumor cells, German investigators from Friedrich-Schiller University in Jena, have shown that neoadjuvant chemotherapy with paclitaxel (taxol) causes a massive release of cells into the circulation, while at the same time reducing the size of the tumor. The finding could help explain the fact that complete pathologic responses do not correlate well with improvements in survival.
In the study, according to Katharina Pachmann, M.D., professor of experimental oncology and hematology, breast cancer patients undergoing neoadjuvant chemotherapy gave blood samples in which epithelial antigen-positive cells were isolated. Such cells are detected in most breast cancer patients but are rarely found in normal subjects. The investigators measured the levels of cirulating tumor cells before and during primary chemotherapy with several different cytotoxic agents. (Oncol News Int'l, Vol 14, #5, May '05)
Paclitaxel (taxol) produces the greatest degree of tumor shrinkage but also the greatest release of circulating tumor cells. In three different paclitaxel-containing regimens, circulating cell numbers massively increased, whereas tumor size decreased. These cells remained in the circulation for at least five months after surgery.
The tumor shrinks, but more cells are found in the circulation. This corresponds with a high pathologic complete response during paclitaxel treatment, but in the end, this is not reflected in improved survival. These cells are alive in the circulation. The results indicate that monitoring of circulating tumor cells can contribute to understanding of tumor-blood interactions and may provide a valuable tool for therapy monitoring in solid tumors.
What this recent study has shown, so far, that in three different paclitaxel (taxol) containing regimens, as the tumor collapses (a clinical response, not cure), it produces the greatest release of circulating tumor cells. The study has not looked at any other combination regimens.
Even if one or more chemotherapy regimen is identified as being likely to work on a particular cancer, has the science advanced to tell us whether application of the chosen chemotherapy regimen will not cause other changes that also cause cancer to later return and perhaps be even harder to treat? Is it a case of chemotherapy being bad, in cases where it apparently works? |
|
Search 
Email Digests
Register to post
Profile 
Check private messages 
Log in
What is this ?
We subscribe to the HONcode principles. Verify here. All content and posts are copyright.
