Is Preoperative Chemotherapy More Effective in Breast Cancer Patients?
May 15, 2007 by Gloria Gamat
Filed under Diseases & Conditions
According to a new systematic review, when chemotherapy is given to women with operable breast cancer before having the surgery (not after), it helps oncologists to pin down the best treatment regimen and can reduce the extent of surgery.
Preoperative chemotherapy reduced chemo-related infections by 4 percent and the need for mastectomies by 17 percent when compared to postoperative chemotherapy.
The said review was led by Sven Mieog, M.D., of Leiden University Medical Center in the Netherlands.
As rationalized by the experts, the advantages of preoperative chemotherapy are:
- tumors are already shrunk before surgery
- allows the doctors to see if a tumor is resistant to a particular drug and can already adjust the dose or switch to another drug after surgery
- increased breast conservation rate
Although the survival rates in both groups (preoperative and postoperative chemotherapy groups) were not affected, the data from this review revealed a higher recurrence rate in women who had chemotherapy before surgery while chemotherapy side effects (i.e. nausea, hair loss, etc.) were found similar in both groups.
Furthermore, no detectable significant difference in the overall survival rates in both groups.
That been itemized…now I’m wondering whether there really is a big advantage of preoperative chemotherapy over postoperative chemotherapy. I guess aside from breast conservation?
The said review appears in the current issue of The Cochrane Library, a publication of The Cochrane Collaboration.
Find more details from the full report.
Be mindful, the mutagenic effects of the wrong chemo can start the chain of metastatic events. A chemo-induced gene mutation can happen when the original chemo received does not work. The cancer comes back. When it does this, the tumor comes back more aggressively. The mutagenic effects (changes in form) of chemotherapy on a genetically-unstable tumor, drives the tumor into a state of more aggressive behavior. 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 aggressive fashihon.
Shrinking tumors is a totally inadequate measure of the effectiveness of a drug. German investigators, using the CellSearch system, showed that Taxol produced the greatest degree of tumor shrinkage, but also the greatest release of circulating tumor cells, beginning the most life-threatening aspect of cancer, metastasis. With cells remaining in the circulation, this observation corresponds with results found in patients that tumor response does not mean increased survival.
Some researchers believe the reason for better survival for patients who could undergo complete resection without any tumor left behind is that these tumors are biologically less aggressive and would do better regardless of the type of treatment they receive, and that the removal of lymph nodes at the time of surgery may additionally contribute to a better outcome. Surgery is an integral part of the multimodality treatment of many cancers.
The line of reasoning frequently used to explain the value of surgery included five points: First, surgery is thought to remove resistant clones of tumor cells and thus decrease the likelihood of the early onset of drug resistance. Second, the removal of large masses likely to be associated with poorly vascularized areas of tumor improves the probability of delivering adequate drug doses to the remaining cancer cells. Third, the higher growth fraction in better vascularized small masses enhanced the effect of chemotherapy. Fourth, smaller masses required fewer cycles of chemotherapy and thus decreased the likelihood of drug resistance. Fifth, removal of bulky disease enhances the immune system.
Mayo Clinic
American Board of Surgeons
Society of Surgical Oncology
Oncol News Int’l, Vol 14, #5, May ‘05