[gdpawel]

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.

2nd, 3rd, even 4th line therapies (why?)

I often read on the discussion boards about oncologists telling patients "if this drug doesn't work, we'll try this drug." And "if that drug doesn't work, we'll try this drug." In patients who have failed two, three or even four chemo drugs, why not give them the "right" drug or combinations the "first" time around?

In academic centers, patients are entered into clinical trials of square peg in a round hole therapy. This encourages the patient to receive 2nd, 3rd, and 4th line chemotherapy, regardless of the likelihood of meaningful benefit. The therapies are equivalent on a "population" basis, but not on an "individual" basis.

They continue to try and mate a notoriously heterogeneous disease into "one-size-fits-all" treatments. They predominately devote their clinical trial resources into trying to identify the best treatment for the "average" patient, in the face of evidence that this approach is non-productive.

According to NCI's official cancer information website on "state of the art" chemotherapy in recurrent or metastatic cancer, no data support the superiority of any particular regimen. There is no proven "standard" first line therapy which has been shown to be superior to the many other choices which exist.

The same situation exists in the setting of 2nd, 3rd, and 4th line therapy. Proven by the large number of patients who have progressive disease on 1st line therapy but who have good responses to 2nd or 3rd line therapy.

So it would appear that published reports of clinical trials provide precious little in the way of guidance. These patients patients should have received the "correct" treatment in the first line setting. This can be accomplished by individualizing cancer treatment based on testing the cancer biology.