Table 4.

Relative Risk of Recurrence for Patients with Low and High Genomic Marker Prognostic Indices

	All ER/PR+	ER/PR+ N0	All ER/PR−	ER/PR− N0
Low-risk PI	0.305	0.348	0.265	0
High-risk PI	1.68	2.22	1.70	2.0

Relative risk of assigned category to group risk (test sets). Risks were calculated for each of the four categories of patients (all ER/PR⁺, ER/PR⁺ N0, all ER/PR⁻, and ER/PR⁻ N0) using the test set data only. Relative risk for each risk category was calculated based on the risk of recurrence in each risk category in comparison with the average rate of recurrence for that patient group. Data are summarized for both lymph node-positive and -negative cases. Note that prognostic indices were calculated for ER/PR⁺ and ER/PR⁻ cases only when raw data (signals per NEV) were available for a case for all three chromosome region markers; thus, the number of cases available for this analysis is less than shown in Table 2.