Chasing Mets (metastasis)

On most cancer message/discussion boards, one of the most common themes is that of "chasing mets" (metatasis). Cancer patients are chasing mets because of the wrong type of chemotherapeutic regimens for their type of cancer histology. But why do patients with histologically similar tumors respond differently to so-called "standard" drug treatments? That is one of the main problems associated with chemotherapy. Patient tumors with the same histology do not necessarily respond identically to the same agent or dose schedule of multiple agents.

Medical oncologists select a drug and must wait to see whether it is effective on a particular patient. Conventionally, oncologists rely on clinical trials in choosing chemotherapy regimens. But the statistical results of these population-based studies might not apply to an individual. And when patients develop metastatic cancer, it is often difficult to select an effective treatment because the tumor develops resistance to many drugs. For many cancers, especially after a relapse, more than one standard treatment exists.

A chemoresponse assay is a diagnostic test (not a treatment) to help measure the "efficacy" of cancer drugs. They cannot make the cancer drugs do better, it can only measure the "best" probability of successful drugs. This is in stark contrast to "standard" or "empiric" therapy (also called physician's choice therapy), in which chemotherapy for a specific patient is based on results from prior clinical studies.

Laboratory screening of samples from a patient's tumor (if available) can help select the appropriate treatment to administer, avoiding ineffective drugs and sparing patients the side effects normally associated with these agents. It can provide predictive information to help physicians choose between chemotherapy drugs, eliminate potentially ineffective drugs from treatment regimens and assist in the formulation of an optimal therapy choice for each patient. This can spare the patient from unnecessary toxicity associated with ineffective treatment and offers a better chance of tumor response resulting in progression-free and overall survival.

It would be highly desirable to know what drugs are effective against particular cancer cells before cytotoxic agents are systemcially administered into the body. Chemresponse assays are clinically validated drug tests on living (fresh) specimens of cancer cells to determine the optimal combination of chemotherapy drugs. These assays are specifically tailored for each individual patient based on tumor tissue profiling, with no economic ties to outside healthcare organizations, and recommendations are made without financial or scientific prejudice.

Recommendations are designed scientifically for each individual patient. Various assays are performed on a tumor sample to measure drug activity (sensitivity and resistance). This will determine not only what drug or combinations of drugs will not effectively work, but which will be most effective for an "individual's" cancer. Then a treatment recommendation is developed through what is known as "assay-directed" therapy.