The first step is to examine the inclusion criteria, the list of conditions you must meet in order to be considered for participation in a certain clinical trial. It's easy to find the list inclusion criteria, since they're featured prominently in every clinical trial listing, even those that are very brief.

You'll learn very quickly, for example, that a certain clinical trial is looking for people with Stage III or Stage IV non-small-cell lung cancer. If you have Stage II lung cancer, or small-cell lung cancer, or a different kind of cancer entirely, it's pointless even to make a phone call to investigate the trial further, no matter how promising you believe the treatment to be. You simply won't be considered if you don't meet the inclusion criteria.

If you seem to meet the inclusion criteria, the next step is to phone (or to have a friend, relative, or your physician phone) the investigator or the clinical trial coordinator. The first thing she'll do will be to ask you about your diagnosis. She may have a more detailed list of inclusion criteria than those that were in the brief clinical trial description. If you still seem eligible, she'll go over the exclusion criteria.

This is where most potential participants in the clinical trial fall out. In many trials more than 90 percent of people inquiring about a clinical trial are excluded. Dr. David Jablons, a thoracic surgeon and cancer expert at the University of California, San Francisco explains:

The typical clinical trial in cancer is not being done in early stage patients who have the luxury, hopefully, of a long disease-free interval. On the contrary, it's being done on patients with advanced disease who are desperate for any potential, hopeful, experimental therapy. The problem is that the studies usually (but not always) are looking at patients that are freshly diagnosed with advanced disease who haven't seen a lot of therapy to date. It helps keep the data cleaner. If you have a Substance X that you think is really going to be effective, and you start it on patients who have never seen any chemotherapy, who have never had any radiation, then it's pretty easy to say that the result is due to the trial drug. On the other hand, if they've had a bunch of chemotherapy and then you give them Substance X, the data are not as clean.

It's really a paradox. The patients who are the most desperate, the most motivated, and the most interested in innovative therapy plans are usually the patients who have failed conventional therapy.

Sometimes the rules can be bent. For example, if they've had radiation a year ago, focal radiation might not rule a patient out. But if a person has failed fourteen different drugs as of a month ago, and their disease is rapidly progressing, is that the right person to try a new substance on? It could be, because if you saw a response, you'd say that not only is Substance X effective, but it's effective as a salvage treatment. The problem is that these are rapidly progressing diseases. Clinical disease doesn't always wait for careful, controlled, cautious, trial progression.