Like most medical specialties, oncology is part art and part science. There’s plenty of room for individualizing treatment plans, but as a specialty we try be evidence-based. These are treatments that can be very helpful for patients, but also can have significant side effects, so we want to be guided by as much information as possible about the anticipated risks and benefits of treatment. I’ve been using the terminology of oncology trials throughout all of these discussions, so I wanted to take some time to discuss what the terms mean and how to interpret a survival curve. Whether here or from other sources, what you may read can have details that are not necessarily obvious. Here are some of the basics of oncology terminology.

First, trials can be retrospective, which means looking back at results of patients being treated a certain way, or prospective, which means that patients who have a similar cancer and stage are assigned a uniform treatment plan. Prospective trials are generally more informative, but retrospective reviews of information can provide good hints of whether certain patients respond well to a treatment, for instance, or whether others with a certain tumor histology develop a particular side effect.

As I mentioned in my discussion of drug development, phase III trials are randomized, which means that there is essentially an electronic coin flip between treatment A and treatment B. Usually in phase III trials we are testing a new approach vs. the prior standard treatment. Trials can be open-label, in which the doctor and patient know exactly what treatment is being given, single-blinded, in which the doctor/medical team know the treatment but the patient does not, or double-blinded, which is when neither medical team nor the patient know the treatment a patient is getting. Double-blinded trials generally include a placebo, an inactive IV or pill that appears indentical to the active medication. This is to clarify whether the differences between arm A and arm B are truly because of the drug or because of the placebo effect, which describes the range of effects people ascribe to a drug even when it has no active properties. This can be important for many reasons, because patients with progressing cancer may feel increasing pain or cough or fatigue that they ascribe to a new medication rather than to the underlying disease. By the same token, coming off of harsh chemotherapy can leave people feeling better, so a trial of a new treatment that starts after completing challenging treatment may leave people feeling better because of the new drug or just because they’re not doing the harder treatment anymore. Finally, there’s a potentially powerful psychosomatic effect from taking a drug that everyone believes is going to be the next great thing. A placebo helps determine what the active drug is really doing.

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