Impact of Oncotype DX on treatment decisions in ER-positive, node-negative breast cancer with histologic correlation.

Oncotype DX, a gene-expression profiling assay, provides stratification of patients with estrogen-receptor positive, lymph-node-negative early breast cancer into risk groups based on recurrence score, which are associated with distant recurrence and response to chemotherapy. This study aims to determine whether Oncotype DX influences clinicians' treatment decisions, and whether assay results correlate with histologic assessment. Fifty patients with estrogen-receptor positive, node-negative early breast cancer analyzed by Oncotype DX and operated on by two breast surgeons were included. To assess effect on treatment decisions, clinical vignettes were created by retrospective chart review. Physicians were then presented with the clinical vignettes and instructed to make a treatment decisions (i.e., hormone therapy alone versus hormone therapy combined with chemotherapy) both before and after knowledge of the recurrence score. To assess correlation with histologic assessment, a prospective, blinded review of tumor slides was performed by two pathologists. Based on this review, tumors were placed into low, intermediate and high risk groups for comparison with Oncotype DX assay results. Treatment decisions were changed based on Oncotype DX results in 36 and 18% of cases by breast surgeons and medical oncologists, respectively. All tumors categorized as high risk by Oncotype DX were categorized as high risk based on histologic assessment, and 96% of cases categorized as low risk by recurrence score were categorized as low or intermediate risk by histologic assessment. Oncotype DX significantly influences management of estrogen-receptor positive, lymph-node-negative early breast cancer. Further studies are needed to assess association of histologic categorization to assay results.

P300-based detection of concealed autobiographical versus incidentally acquired information in target and non-target paradigms.

The basic rationale of P300-based tests of concealed information compares responses to critical ('probe') and non-critical ('irrelevant') items. Accuracy, both in the laboratory and the field, is the degree to which responding to probes exceeds that to irrelevants. The present laboratory study assessed the influence of two factors on accuracy. The first, varied between subjects, was whether the paradigm included probes, irrelevants, and target items (as is the case in most P300 preparations), or whether the paradigm included only probe and irrelevant items. The second, orthogonally varied, within-subject factor was whether the probe was an autobiographical item (the subject's name), or incidentally acquired (as in common field applications). Accuracy was greater with the subject's name as probe, perhaps because of the greater potency of autobiographical items than incidentally acquired ones, even when these are learned to a 100% accuracy. On the other hand, contrary to expectations from a work-load interpretation, the removal of the target did not affect accuracy, but rather decreased P300 magnitude to both probes and irrelevants in the non-target group.

Subjective and objective probability effects on P300 amplitude revisited.

Does objective probability affect P300 size independently and in addition to subjective probability? The latter was manipulated by the number of stimuli presented and classification task. Five groups saw target and frequent stimuli. Two saw these with p=.2 or .067, with two different button presses. Three groups saw two additional nontarget stimuli each with p=.067. One group pressed a different button for each stimulus. A second group pressed one button for the three oddballs, another for the frequent. A third critical group pressed one button for the target and another for other stimuli. In this group, P300 was larger for targets versus nontargets, and larger for nontargets versus frequents. Although nontargets were classified with frequents, their actual low probability distinguished them from frequents, and their subjective probability distinguished them from targets. Therefore, actual and subjective probability effects were independently found.