A variety of endpoints may be measured and reported from clinical studies in oncology. These may include total mortality (or survival from the initiation of therapy), cause-specific mortality, quality of life, or indirect surrogates of the four outcomes, such as event-free survival, disease-free survival, progression-free survival, or tumor response rate. Endpoints may also be determined within study designs of varying strength, ranging from the gold standard—the randomized, double-blinded controlled clinical trial—to case series experiences from nonconsecutive patients. The PDQ editorial boards use a formal ranking system of levels of evidence to help the reader judge the strength of evidence linked to the reported results of a therapeutic strategy. For any given therapy, results can be ranked on each of the following two scales: (1) strength of the study design and (2) strength of the endpoints. Together, the two rankings give an idea of the overall level of evidence. Depending on perspective, different expert panels, professional organizations, or individual physicians may use different cut points of overall strength of evidence in formulating therapeutic guidelines or in taking action; however, a formal description of the level of evidence provides a uniform framework for the data, leading to specific recommendations.
The PDQ Adult Treatment Editorial Board and the PDQ Pediatric Treatment Editorial Board add information on levels of evidence, described below, to the PDQ Adult Cancer Treatment Summaries and the PDQ Pediatric Cancer Treatment Summaries when appropriate.
PC-SPES is a mixture of 8 herbs that was sold as a dietary supplement to keep the prostate healthy (see Question 1).
Some batches of PC-SPES were found to contain prescription medicines. It was taken off the market and is no longer being made (see Question 1).
Herbs in PC-SPES have been used in traditional Chinese medicine for many health problems, including prostate problems, for hundreds of years (see Question 2).
The herbs used in PC-SPES have been reported to help keep cancer cells...
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.gov or call 1-800-4-CANCER.
WebMD Public Information from the National Cancer Institute
September 04, 2014
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