Validation of a financial toxicity (FT) grading system.

6615 Background: FT is an important adverse event (AE) that should be objectively measured in clinical practice. We previously developed an evidence-based FT grading system based on differences in HRQoL, analogous to the NCI-Common Terminology Criteria for Adverse Events (grade 1, mild AE; grade 2, moderate AE; grade 3, severe AE ,de Souza et al - ASCO 2015). We aimed to validate this grading system using a new sample of cancer patients (pts) and report its association with bankruptcy. Methods: FT was assessed by the COST (COmprehensive Score for financial Toxicity) in 2 sets of cancer pts. In the previously reported Development Set (DS), gradations of FT were determined by ROC analyses based on conventions for clinically meaningful small (0.2), medium (0.5) and large (0.8) effect sizes (e.s.) for independent FACT-G differences attributable to FT in pts with Stage IV cancers on chemotherapy. In the Validation Set (VS), differences in HRQoL and the odds ratio for a pt to have declared bankruptcy after the cancer diagnosis were assessed in a larger cohort of cancer pts on chemotherapy. Results: The grading system was developed in 888 cancer pts with cancer (233 pts in the DS and 655 in the VS). In the DS, ROC analyses produced 4 FT grades (G): G0, no FT, COST ≥26 (99 pts, 42%); G1, mild FT: ≥ 14-26 (71 pts, 31%); G2, moderate FT: > 0-14 (58 pts, 25%); and G3, severe FT: COST = 0 (5 pts, 2%). Applying the FT grading to the 655 pts in VS, we had: G0, 146 pts (22%); G1, 281 (43%); G2, 215 (33%); and G3, 13 (2%). The decreases in FACT-G HRQoL measured in e.s. per FT grading in comparison with G0 were small for G1: -0.4 (95%CI: -0.6 – -0.25); large for G2: -0.9 (95%CI: -1.1 – -0.7); and even larger for G3: -1.5 (95%CI: -2.0 – -0.9), all with p < 0.001. In the VS, 23 pts (4%) had declared bankruptcy after their cancer diagnosis. Compared to FT G0, the odds of having declared bankruptcy were 8.6 (95%CI: 1.1 – 67, p = 0.04) times higher for pts with FT G2, and 29 times higher (95% CI: 2.4 – 355, p = 0.008) for those with G3 FT. Conclusions: We developed a FT grading system anchored on independent differences in HRQoL. We applied the system in a different set of cancer pts and it retained its validity. We also found an larger incidence of bankruptcy after the cancer diagnosis in higher grades of FT, adding to the grading’s meaningful use.