Cancer patients’ and physicians’ preferences for decision making regarding pharmacogenomic testing (PGT).

Abstract

13 Background: Pharmacogenomics is increasingly utilized in oncology; however, there is little knowledge concerning cancer patients’ or oncologists’ attitudes toward PGT decision-making in clinical practice. Methods: A broad cross-section of cancer patients were interviewed regarding their attitudes toward PGT using hypothetical time, efficacy and toxicity trade-off and willingness-to-pay scenarios (N=278) and/or quantitative choice-based conjoint analysis surveys (N=264); 64 cancer specialists/physicians in training were surveyed similarly. Results: Of patients participating in the trade-off scenario phase of study, >94% accepted chemotherapy, and of these, >98% wanted PGT that identifies a subset of patients either benefiting from chemotheraphy or who were at risk of severe toxicity. Patients were willing to pay between CAD $1,000-$1,900 for PGT and accept wait times for results of 2-3 weeks. Similar findings were observed in the conjoint phase of the study, with preferences for PGT starting to decline when the out-of-pocket costs reached CAD $500-$1,500, wait time for results exceeded 14 days, and when the prevalence of the genetic variant fell below 25%. Adjuvant patients’ acceptance of PGT was most influenced by cost (decision weight [DW]=41%) and prevalence of the genetic variant associated with lack of benefit from chemo (DW=26%). Metastatic patients were most influenced by cost (DW=49%) and wait times (DW=31%). More patients reported difficulty understanding conjoint surveys (14%) than trade-off scenarios (7%; p=0.01). 81% of patients wanted to be involved in decision-making regarding PGT; while 30% of physicians felt it should be a physician-only decision (p=0.006). However, 21% of patients and 5% of physicians admitted to not understanding PGT, while just 14% of physicians rated themselves as very knowledgeable regarding PGT. Conclusions: Cancer patients overwhelmingly accept and want to be involved in decision-making regarding PGT, to a greater extent than what physicians prefer. However, communication of PGT information was a potential barrier, as a considerable minority lacked the necessary knowledge to facilitate informed decision-making. Improved patient and physician education is necessary.