Knowledge Synthesis in Evidence-Based Medicine.

Systematic reviews are the most common form of knowledge synthesis and remain a cornerstone of the practice of evidence-based medicine. They offer enhanced rigor and validity relative to traditional narrative review articles by reducing bias and increasing objectivity. In answering focused research questions, systematic reviews are directly applicable to clinical practice as well as the development of clinical guidelines and the identification of knowledge gaps, which may drive future primary research directions. Typically, such a rigorous process necessarily requires substantive time to carefully and systematically identify, screen, and synthesize all relevant available primary research on a topic. Further, other knowledge synthesis methods have emerged to address the varying needs of decision makers with respect to condensed timelines and more diverse research questions, as well as to allow incorporation of already synthesized evidence into reviews. These alternative methods include rapid reviews, scoping reviews, and overviews of systematic reviews, which are being used with increasing frequency by clinicians, decision-makers, and researchers. We encourage clinicians and researchers in nuclear medicine and other imaging sciences to acquire a greater familiarity with these methods and to consider them in clinical decision making, the development of clinical guidelines, and the planning of future research activities.

Effects of radiation and total androgen blockade on serum hemoglobin, testosterone, and erythropoietin in patients with localized prostate cancer.

OBJECTIVE: The objective of the present study was to evaluate the incidence, time of onset, and extent of hemoglobin, testosterone, and erythropoietin changes in patients with localized prostate cancer receiving either radiation alone or radiation combined with total androgen blockade (tab). METHODS: The study enrolled 35 patients (median age: 69 years) with clinically localized prostate cancer who received 3-dimensional conformal radiation with or without tab. Patients were generally treated with radiation alone (group 1), radiation plus short-term (≤6 months) tab (group 2), or radiation plus long-term (≥2 years) tab (group 3). Serum hemoglobin, testosterone, and erythropoietin in these patients were prospectively evaluated. RESULTS: The mean baseline serum hemoglobin for group 1 (n = 20), group 2 (n = 6), and group 3 (n = 9) was 149 g/L, 153 g/L, and 143 g/L respectively. We observed no significant decline in serum hemoglobin, testosterone, or erythropoietin among patients treated with radiotherapy alone. A significant drop in serum testosterone was noted in the group 2 and 3 patients within 1 month (p < 0.001), reaching a plateau at approximately 6 months. That change was followed by a significant decline (p < 0.001) in serum hemoglobin at 3-6 months (137 g/L in group 2 and 129 g/L in group 3). We observed a small but statistically significant increase in serum erythropoietin (p < 0.001) of 8 U/L in group 2 and 4 U/L in group 3 after 6 months of tab. No immediate recovery in serum hemoglobin, testosterone, or erythropoietin was observed upon completion of tab. CONCLUSIONS: Although conformal radiotherapy alone for localized prostate cancer had no effect on serum hemoglobin, testosterone, or erythropoietin, tab led to a significant decline in testosterone, which was followed by decline in hemoglobin that was not a result of a deficiency of erythropoietin.