Has anyone had chemosentistivity testing of their tumor.

VeronicaX

Hi everyone,

I have been diagnosed with breast cancer in November and had a mastectomy in December. I do not have the pathology results yet, but the tumor was quite big. I sent a speimen to US for chemosensitivity testing and i was wondering if enyone else had that done and if thier oncologist wanted to take it into considertation. I head that in US chemosensitivity testing is standard of care and in Canada is not yet accepted even though big hospitals such as Princess Margaret do ther own testing.

Thanks

V

gpawelski

Veronica

Unfortunately, for cancer patients, chemosensitivity testing is not "standard of care" in the US also. When clinically relevant and accepted drugs may have the same efficacy, it is within the "standard of care" to give the drug with the least "resistance" and/or the drug with the most "sensitivity." That is exactly what chemosensitivity testing is doing. This reinforces the need for cancer therapies to be "individualized." It reminds us that it s the good outcome of the patient, not the therapy applied that constitute successful therapy.

Frequently, the "standard of care" for a particular type or stage of cancer involves the "off-label" use of one or more drugs. This is what chemosensitivity testing does also. The US FDA does not have the legal authority to regulate the practice of the medicine and the physician may prescribe a drug off-label. Some drugs are used more frequently off-label than for thei original, FDA-approved indications. Some have suggested to use chemosensitivity assays to identify the potential targeted population of these patients that it thinks will benefit from any drugs, singularly or in combination.

Cocktails have become standard treatment in many oncological protocols: concoctions of two or more powerful cytotoxic agents which supposedly will attack the tumor in different ways. The ability of various agents to kill tumor and/or microvascular cells (anti-angiogenesis) in the same tumor specimen is highly variable among the different agents. There are so many agents out there now, doctors have a confusing array of choices. They don't know how to mix them together in the right order.

Data show conclusively that patients benefit both in terms of response and survival from drugs and drug combinations found to be 'active' in functional profiling assays even after treatment failure with several other drugs, many of which are in the same class, and even with combinations of drugs found to have low or no activity as single agents, but which are found in the assay to produce a synergistic and not merely an additive anti-tumor effect.

Source: Weisenthal Cancer Group, Huntington Beach, CA and Departments of Clinical Pharmacology and Oncology, Uppsala University, Uppsala, Sweden. Current Status of Cell Culture Drug Resistance Testing May, 2002.

SelenaWolf

That makes a great deal of sense.  I mean, when you have an infection, they do a sensitivity culture to see which antibiotic will work the best.