Cell cycle progression score and treatment decisions in prostate cancer: results from an ongoing registry.

OBJECTIVE: The cell cycle progression (CCP) test (Prolaris) is a novel prognostic assay that provides accurate risk of prostate cancer-specific disease progression and disease specific mortality when combined with standard clinicopathologic parameters. This prospective study evaluated the impact of the CCP report on physician treatment recommendations for prostate cancer. METHODS: Physicians ordering the CCP test in clinical practice completed surveys regarding treatment recommendations before and after they received and discussed the test results with patients. Clinicians also rated the influence of the test result on treatment decisions. Treatment selections were confirmed via third-party audit of patient charts following final survey responses. RESULTS: Overall, 65% of cases showed a change between intended treatment pre- and post-CCP test reporting. Pre-CCP testing, 164 of 305 cases received a recommendation for interventional treatment. Post-CCP test, interventional therapy was recommended for 103 of these cases, a reduction of 37.2%. Conversely, 141 of 305 cases were recommended pre-CCP testing for non-interventional treatment; 108 of these remained with non-interventional treatment while 33 shifted to interventional options, a 23.4% increase. There was a 49.5% reduction in surgical interventions and a 29.6% reduction in radiation treatment. A third-party audit identified 80.2% concordance between the post-CCP testing treatment recommendation and actual treatment. Re-assignment to intervention or non-intervention generally correlated with the result of the CCP report. Study limitations included physician selection of patients for testing, no evaluation of patient input in therapeutic choice, and other potential treatment decision factors not queried by the survey. CONCLUSION: Based on responses of ordering physicians, the CCP report adds meaningful new information to risk assessment for localized prostate cancer patients. Test results led to changes in treatment with reductions and increases in interventional treatment that were directionally aligned with prostate cancer risk specified by the test.

Modeling the 5-fluorouracil area under the curve versus dose relationship to develop a pharmacokinetic dosing algorithm for colorectal cancer patients receiving FOLFOX6.

BACKGROUND: 5-Fluorouracil (5-FU) is administered based on standard body surface area (BSA) dosing. BSA administration results in highly variable exposure, measured as the area under the concentration-time curve (AUC). An immunoassay (OnDose®; Myriad Genetic Laboratories, Inc., Salt Lake City, UT) that measures plasma 5-FU concentration and reports an AUC in mg · h/L has been developed to optimize therapy using pharmacokinetic (PK) dosing. The results of an analysis to model the 5-FU AUC-dose relationship are presented. METHODS: A set of 589 sequential patients from a clinical database receiving 5-FU, leucovorin, and oxaliplatin (the FOLFOX6 regimen) for colorectal cancer (CRC) treatment was analyzed. A subset including only patients who had at least two consecutive cycles tested, received 1,600-3,600 mg/m2 of continuous infusion 5-FU during the initial test cycle, and had a blood sample collected after ≥18 hours, was used to conduct regression modeling of the change in AUC versus change in dose. RESULTS: A simple regression model with R(2) = 0.51 developed over n = 307 cycle-pair observations characterizes the AUC-Dose relationship as: change in AUC = 0.02063 * dose change. The model suggests that dose changes in the range of 145-727 mg/m2 would be sufficient to adjust the AUC to a potential therapeutic threshold of >20 mg · h/L for most patients. CONCLUSIONS: 5-FU is an ideal candidate for PK dose optimization. Because individual factors other than dose change may also affect the change in AUC, longitudinal PK monitoring in all cycles and dose adjustment to ensure AUC in the desired range of 20-30 mg · h/L are recommended.