Benefit assessment of PET in malignant lymphomas. The IQWiG point of view

Abstract

The call by the Institute for Quality and Efficiency in Health Care (IQWiG) for randomised controlled trials (RCTs) to prove the patient-relevant benefit of positron emission tomography (PET) is currently a controversial topic in Germany. From a methodological point of view there is essentially no difference between diagnostic procedures and therapeutic (drug or non-drug) interventions in proving their causal benefit. A broad consensus has been reached since the 1960s (e.g. FDA regulations) that RCTs are the methodological gold standard for therapeutic interventions. Nevertheless, the same arguments that were cited against RCTs in assessing the benefit of therapeutic interventions are now used against RCTs in evaluating diagnostic tests (e.g. ethical problems, feasibility, etc.). This paper summarizes the central methodological arguments of the discussion on the benefit assessment of PET in malignant lymphomas from the perspective of IQWiG and its external experts.

Comparing diagnostic tests: trials in people with discordant test results

“…Given the time and money that must be spent on a trial, the need should be considered carefully given the available evidence, of which cross‐sectional studies will form an important part. Trials are, nevertheless, established as the gold standard of evidence when evaluating interventions in an unstratified context, and there has been some discussion about whether regulators should require prospective validation with a large phase III trial before any new tool—including a testing strategy—can be accepted as the standard of care . Methodology for the evaluation of diagnostic tests and biomarkers will remain an active research area.…”

Generating Evidence for Clinical Benefit of PET/CT in Diagnosing Cancer Patients

“…Often, however, a qualified guess about the direction of the effect can be made, allowing a lower bound for the benefit, an upper bound for the benefit, or both to still be determined. This approach is often sufficient, because if lower bounds are known for b 1 and b 2 and upper bounds are known for the absolute values of the negative benefits b 3 and b 4 , then a lower bound for the overall benefit can be obtained.…”

Positron emission tomography 2008 in Germany

“…Ein (14,22). Im Vergleich zu 1999 hat sich jedoch die Untersuchungsfrequenz verdreifacht (5), wurden Leitlinien zur Qualitätssicherung erstellt (15) und ist die PET-Diagnostik in interdisziplinären Leitlinien verankert (10,23).…”