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CancerGuide: Clinical Trials and Experimental Treatments

Introductory Articles
In-Depth Guide
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Clinical Trials Dictionary
Clinical Trials Dictionary

This will help you understand words and phrases that you will find in clinical trials databases such as the NCI's PDQ database, as well as terms you will find in reading journal articles. I have included terms which apply to clinical trials generally, but have not included terms relating to specific treatments or particular types of cancer. If you come across any terms that you think should be included, please drop me a line. For a more systemic view of the clinical trials system see Steve's Guide to Clinical Trials. For where to search for clinical trials on the net, see CancerGuide's Internet Clinical Trials page.


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Accrual
The process of getting patients into a trial, or the number of patients in a trial or planned to be in a trial. For example, "Projected accrual 14" means they are planning to treat 14 patients in the trial. "Accrual completed" means they've got all the patients they planned for the trial. The trial is probably closed to new patients.
Adjuvant Treatment
"Secondary" treatment that is given after all visible disease has been removed by a primary treatment. Adjuvant Treatment is given in the hopes of preventing a recurrence of the cancer. For example, chemotherapy for colon cancer given after surgery is Adjuvant Treatment. Compare Neo-Adjuvant.
Adjuvant Trial
A clinical trial of an Adjuvant Treatment. Most Adjuvant Trials are randomized.
Arm
Any of the treatment groups in a randomized trial. Most randomized trials have two arms, but some have three arms or even more.
Blind
Used with respect to a randomized trial, a randomized trial is Blind if the patient is not told which arm of the trial he is on. See also Double Blind
Complete Response
All detectable cancer is now gone after treatment. There can still be cancer left, but too little to detect, so a Complete Response is not the same thing as a cure, although some patients with a Complete Response may be cured.
Control Group
The arm of a randomized trial which gets the standard treatment. In some randomized trials, both of the treatments are standard treatments, or both equally well known new treatments, and in such cases it is not appropriate to speak of a Control Group. See also Experimental Group
CR
See Complete Response
Disease Free Survival
Time the patient survives without any detectable cancer. Contrast Progression Free Survival.
DLT
See Dose Limiting Toxicity
Dose Limiting Toxicity
Size-effects that are severe enough to prevent giving more of the treatment. See Phase I Trial for more information.
Double Blind
Used with respect to a randomized trial, a randomized trial is Double Blind if neither the patient or his doctor are told which Arm of the trial he is on. This information is kept at a central office, and is typically revealed only at the end of the trial. The purpose is to prevent any bias in treatment or reporting of results from creeping in. See also Blind
ECOG Status
The Eastern Cooperative Oncology Group scale for measuring performance status on a scale from 0 to 4. Most trials require ECOG 0 or 1, but it is not unusual to find trials that admit patients with ECOG status 2. Only very few trials admit patients with ECOG status 3. It can be hard to objectively rate your own performance status. I considered myself profoundly disabled when I entered my trial, but I was only ECOG 1, so I recommend letting your physician answer any questions about your performance status. See also Karnofsky Status.

ECOG Performance Status Scale and Comparison to Karnofsky Status
ECOG Status Meaning Karnofsky Status
0 No Symptoms, fully active, able to work 100
1 Symptomatic, but not spending extra time in bed. Able to do light work 80 or 90
2 In bed less than 50% of the day, unable to work, but can take care of self. 60 or 70
3 In bed more than 50% of the day, but not bedridden, limited self care 40 or 50
4 Completely bedridden 20 or 30

End Point
What a clinical trial is trying to measure or find out. In essence, the goal of the trial. It is scientifically very important that the goals for clinical trials be selected and clearly defined in advance. Typical end points include measurements of Toxicity, Response Rate, and Survival
Evaluable Disease
A tumor or tumors which you can tell are present but the size of which cannot be measured accurately. For example, for technical reasons, bone metastases are hard to measure exactly and are usually counted as Evaluable Disease. The same is true for Pleural Effusions, and Ascites (fluid in the abdomen). Contrast Measurable Disease.
Experimental Group
The Arm of a randomized trial which gets the new or "experimental" treatment. In some randomized trials, both of the treatments are standard treatments, or both equally well known new treatments, and in such cases it is not appropriate to speak of an Experimental Group. See also Control Group.

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Grade
This can refer to how abnormal and aggressive the cancer cells appear to be when examined with a microscope, and is rated with a numeric scale, usually I through IV. See the CancerGuide article on Understanding Cancer Types and Staging for more detailed information on Grade.

In the context of clinical trials, grade can also refer to a numeric scale to rate the severity of toxicity from a treatment. Each specific side-effect such as "nausea and vomiting" is rated on a scale from 0-4. Grade 0 toxicity always means the size-effect isn't present, grade 1 means it is present but relatively minor, grade 2 means it is moderate, grade 3 means it is severe, and 4 means it is potentially life threatening. The exact definition of each number in the scale depends on the particular side-effect. Treatments are often stopped or temporarily delayed for grade 3 or 4 toxicity. Sometimes treatments are resumed at a lower dose.
Hepatic
Pertaining to the Liver.
Histologically Confirmed
The diagnosis of cancer has been confirmed by examining some of the cancerous tissue under the microscope. If you had surgery or a biopsy that revealed cancer, then your cancer has been Histologically Confirmed. Most trials require Histological Confirmation in order to be completely sure that the patients in the trial really have cancer, and really have the type of cancer that the trial requires.
Informed Consent
The process of learning enough about a trial's possible risks and benefits so that you are informed enough to be able to agree to be a part of it. The Informed Consent process includes discussions with the doctor who will be overseeing your treatment in the trial, and, if you decide to join the trial, culminates in the signing of a document outlining what treatments the trial is testing, and the risks and benefits, as well as alternatives to taking part in the trial. This is called the Informed Consent Document and sometimes people just refer to it as the "Informed Consent." It is written in simple language so that everyone can understand it. In my experience, the quality of the Informed Consent document varies quite a bit from trial to trial, but they tend to emphasize the risks and say very little about the benefits or alternatives. A great deal more information is contained in the Protocol Document, which may be available from one of the doctors conducting the trial, but the Protocol Document is also highly technical.
Institutional Review Board
An ethics board which reviews clinical trials to make sure they conform to ethical standards, and to make sure that the Informed Consent document is adequate. All reputable clinical trials will have been approved by an Institutional Review Board, and most hospitals have an Institutional Review Board.
IRB
See Institutional Review Board
 
Karnofsky Status
A performance status scale which rates the severity of your symptoms, and degree of disability on a scale from 100% (no symptoms) to 0%(dead). See also ECOG Status.

Karnofsky Performance Status Scale
Karnofsky Status Meaning
100% No Symptoms
90% Able to carry on normal activity; minor signs or symptoms of disease
80% Able to carry on normal activity with effort; some signs or symptoms of disease
70% Cares for self, unable to carry on normal activity or do active work
60% Requires occasional assistance but is able to care for most of own needs
50% Requires considerable assistance and frequent medical care
40% Disabled; requires special care and assistance
30% Severely disabled; hospitalization indicated although death not imminent
20% Very sick; hospitalization necessary; active supportive treatment necessary.
10% Moribund, fatal processes progressing rapidly
0% Dead

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Maximum Tolerated Dose
The highest dose of a drug, drug combination, or other treatment that most people can safely withstand. The MTD is determined by a Phase I Trial.
Measurable Disease
Tumors whose size can be clearly measured. Examples are lung nodules which can be clearly separated from other tissue on X-Rays, or lumps which can be felt manually or seen with the naked eye and measured. Most Phase II trials require that the patient have Measurable Disease so that any response can be clearly measured. If only some of the tumors can be measured, the patient still has Measurable Disease. Contrast Evaluable Disease
Metastasis
A "secondary" tumor that is in a location remote from the original "primary" tumor. Cancer cells often escape from the primary tumor and take up residence in distant parts of the body such as the lungs, liver, bones, or brain. These escaped cancer cells can multiply so that new tumors form at these secondary locations. Metastasis can also refer to the process by which metastases form. A cancer which has spread is said to be metastatic.
MTD
See Maximum Tolerated Dose.
Multicenter
Refers to a study that is being done at several hospitals at once. If you see a study listed as multicenter you may want to choose a center based on how close to you it is, how experienced they are with this type of treatment, or financial aid they offer. You should be able to get the complete list of participating doctors from anyone involved with the trial.
Neo-Adjuvant Treatment
Treatment for locally advanced disease that attempts to reduce the size of the tumor so that it can be completely removed by other means. For example, chemotherapy given as the first therapy for a large breast tumor may cause the tumor to shrink to the point where it can be completely removed by surgery, or may permit a less radical operation than would have been needed to remove it before chemotherapy was given. Compare Adjuvant Treatment.
Objective Response
See Response
Open Label Trial
A trial which is not Blinded: A trial in which both the doctors and patients know what treatment is being given. Note that an Open Label Trial can be Randomized, or non-randomized, as long as the patients and doctors know what treatment has been assigned. Contrast with Blind
Partial Response
Roughly speaking, a decrease in the amount of cancer of at least 50%, but less than 100%. More precisely, a decrease in the total cross sectional area of all measurable tumors of at least 50% but less than 100%.
Performance Status
A measure of how disabled you are, or how severe your symptoms are. Specific numeric scales are used. See ECOG and Karnofsky Status. Please note that this is not the same as prognosis. Someone who has just had major surgery or a bone marrow transplant may have a very poor Performance Status, but an excellent prognosis. Conversely, many people with early metastatic disease in organs such as the lungs will have no symptoms and an excellent Performance Status, but depending on the type of cancer, the long term prognosis can be very poor.
Phase I Trial
A trial designed to determine the Maximum Tolerated Dose of a new treatment, such as a new drug that has never before been tried in humans, or a new combination of drugs which have never been tried together in humans. A Phase I Trial is the first human testing of the new treatment, although in Phase I trials of combination therapies, the individual elements may have already been well tested. In a typical Phase I Trial, successive groups of three to six patients, called cohorts, are given the treatment. All patients in a cohort get the same dose. The first cohort tycally gets a very low dose, and the dose is raised in each subsequent cohort until a set number of patients experience Dose Limiting Toxicity. The dose level used for the previous cohort to this last cohort is then taken to be the Maximum Tolerated Dose. This dose is then used in a Phase II trial. A common myth about clinical trials is they are all highly experimental with the patients serving as "guinea pigs" - this is not true of most clinical trials, but it is closest to true for Phase I Trial of a brand new drug. Patients in Phase I Trials must have advanced cancer which is Refractory to any standard treatment. Many Phase I trials are open to patients with all types of cancer, and usually, Measurable Disease is not required, only Evaluable Disease (Unlike Phase II trials). For detailed information on Phase I Trials, see Steve's Strategic Guide to Phase I Trials
Phase II Trial
A trial designed to determine the Response Rate of a new therapy which has already been tested in Phase I trials. In a typical Phase II Trial, 14 to 50 patients with one type of cancer are treated to see how many have a Response. Patients in Phase II trials are usually required to have advanced cancer which is refractory to any standard treatment, and in addition, they must have Measurable Disease. Often several Phase II Trials of the same treatment are done for different types of cancer, and if the results of a Phase II Trial are promising for some type of cancer, then often a second Phase II Trial in the same type of cancer is done to confirm the promising results. If results from a Phase II trial are promising enough the treatment may then be tested in a Phase III trial. If the results are obviously much better than the standard treatment, then it may not be necessary to do a Phase III trial, and the treatment may become standard based on Phase II results. For detailed information on Phase II Trials, see Steve's Strategic Guide to Phase II Trials
Phase III Trial
A trial designed to compare two or more treatments for a given type and stage of cancer. The End Point of a Phase III Trial is usually Survival or Disease Free Survival. Phase III trials are usually randomized trials, so you don't normally get to choose which treatment you get. A typical Phase III Trial has fifty to thousands of patients. Some Phase III Trials compare a new treatment which has had good results in Phase II Trials with an older, well known, standard treatment. Other Phase III Trials compare two treatments, both of which are already in common use. As you can see, some of the treatments in Phase III Trials may be available outside of a clinical trial. For detailed information on Phase III Trials, see Steve's Strategic Guide to Phase III Trials
Placebo
An inert substance such as a sugar pill, that is used as the "treatment" for one arm of a randomized trial, typically a double blind randomized trial. In many cases where the treatment causes obvious side effects, a placebo cannot sensibly be used. If there is no effective standard treatment, the control group may simply get no treatment, other than observation and measures to control symptoms as appropriate. In this case, members of the control group will know that they are in the control group. A very great myth about randomized cancer clinical trials is that the patients in one arm always get just a placebo. The truth is that whenever there is a standard treatment the investigators think may be effective, the control group will at least get that treatment.
PR
See Partial Response.
PS
See Performance Status.
Progressive Disease
The disease is getting worse as documented by tests showing that tumors are growing or that new tumors are appearing. Often trials will specify that patients must have Progressive Disease when they enter the trial so that if there is improvement, it can be assumed to be due to treatment in the trial.
Progression Free Survival
Time during which the patient survives without the cancer getting worse; time during which he is alive and without Progressive Disease.
Protocol
A detailed plan of treatment including the dose and schedule of any drugs used. Also used as a synonym for "Clinical Trial."
Protocol Document
A document which describes the detailed plan for the conduct of the trial, including a complete history of the scientific studies relating to the treatments used in the trial, exactly how the treatment is to be given, including the dose and schedule, how to treat side effects, when to reduce the dose, or take patients off of the trial, the patient eligibility criteria, and what pre-treatment and follow-up testing is required. The protocol document is technical but it can help answer many questions you might have about the trial. Many doctors will give you a copy of the protocol document if you ask for it, but some doctors and companies will not. In my opinion this is unconscionable!
Pulmonary
Pertaining to the lungs.

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Randomized Trial
A clinical trial with at least two arms, in which the decision as to which arm a new patient is assigned is made by chance, for instance, by the flip of a coin, or by using a computer to select randomly. A great myth about cancer clinical trials is that all trials are randomized. This is not true, though most Phase III and Adjuvant Trials are.
Refractory
Refers to disease which is unresponsive to standard treatments. Some cancers can be presumed to be refractory from the start because there is no treatment known to be effective. In other cases, a standard treatment is known, but it doesn't help all patients. But in this case you don't have refractory disease unless you have tried the standard treatment and it didn't work, or unless you cannot take the standard treatment for some reason.
Renal
Pertaining to the Kidney.
Response
A significant decrease in the size of tumors as a result of treatment. See Complete Response and Partial Response.
Response Rate
Percentage of patients experiencing a Complete Response or a Partial Response.
Stable Disease
Roughly speaking stable disease means tumors have remained about the same size with no new ones appearing. Because measurement of tumors isn't perfectly accurate, a small amount of either growth or shrinkage is still classified as stable. Stable disease is not a response and stable disease cases should not be included in response rates. Determining whether reported stable disease cases really mean anything can be quite a challenge. For more on this, see my article, Stable Disease: A Problematic Endpoint
Stage
How far advanced the cancer is in terms of the size of the primary tumor, spread to nearby lymph nodes, and spread to distant sites in the body. Every type of cancer has its own staging system. See the CancerGuide article on Understanding Cancer Types and Staging for more detailed information on staging.
Toxicity
Side effects.
TLA
Three Letter Acronym. See also DLT, IRB, MTD, TLA, ULN.
ULN
Upper Limit of Normal. Typically used in setting a limit for how far above the Upper Limit of Normal a test result is allowed to be for you to qualify for the trial. As in "Bilirubin < 2 X ULN" which means bilirubin less than twice the Upper Limit of Normal. (Bilirubin is a substance in the blood which is often elevated when there are liver problems.)
WHO Status
A measure of performance status which is very similar to ECOG Status. WHO stands for World Health Organization. WHO is an agency of the UN.
Zubrod Status
Another performance status scale, virtually identical to ECOG Status.


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This CancerGuide Page By Steve Dunn. © Steve Dunn
Page Created: 1998, Last Updated: February 7, 2003