Chen Yen-Ying, Tseng Ling-Ming, Yang Ching-Fen, Lien Pei-Ju, Hsu Chih-Yi
Department of Pathology and Laboratory Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC.
National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC; Division of General Surgery, Department of Surgery, and Comprehensive Breast Health Center, Taipei Veterans General Hospital, Taipei, Taiwan, ROC.
J Chin Med Assoc. 2016 Dec;79(12):649-655. doi: 10.1016/j.jcma.2016.06.004. Epub 2016 Aug 29.
Multigene assays are recommended for hormone receptor-positive invasive breast carcinoma to determine the risk of recurrence, but they are highly expensive. We investigated the prognostic values of immunohistochemistry (IHC)-based prognostic models as an alternative to multigene assays.
The risk categories estimated by the IHC-based prognostic models were correlated to those estimated by the multigene assays in 71 cases and the follow-up results in 642 consecutive cases of HER2- luminal-type early breast cancer. Cut-off values of IHC-based models were adjusted based on survival outcome to reveal maximum Harrell C index or based on the maximum positive likelihood ratio correlated to multigene assay.
All investigated IHC-based models could predict the risk of distant recurrence, but their cut-off values required adjustment. Using distant recurrence-free survival (DRFS) to refine the cut-off values could improve the prognostic values. Adjusting the cut-off values using the results of multigene assays, the positive predictive values of an estimate of low risk or low recurrence score (≤ 21) were higher than 90%. On average, 23% of cases got different results of risk assessment after adjustment. Although cut-off values adjusted by multigene assay were not identical to those refined by survival, the adjusted values (17.1 and 23.8) and the refined values (17.5 and 24.5) of the best model (Magee Eq. 1) were close. Among all the evaluated models, Magee equation 2 was the only one without Ki67, and its prognostic values were the lowest. Using 20% as cut-off for Ki67 as suggested by St. Gallen consensus, we could confidently define luminal A cancer.
It is necessary to adjust the cut-off values of IHC-based prognostic models to fit the purpose. If the estimated risk is clearly high or low, it may be reasonable to omit multigene assays when cost is a consideration.
对于激素受体阳性浸润性乳腺癌，推荐使用多基因检测来确定复发风险，但此类检测费用高昂。我们研究了基于免疫组化（IHC）的预后模型作为多基因检测替代方法的预后价值。
在71例病例中，将基于IHC的预后模型估计的风险类别与多基因检测估计的风险类别进行关联，并对642例连续的HER2阴性管腔型早期乳腺癌病例进行随访。基于IHC的模型的临界值根据生存结果进行调整，以揭示最大Harrell C指数，或根据与多基因检测相关的最大阳性似然比进行调整。
所有研究的基于IHC的模型都可以预测远处复发风险，但它们的临界值需要调整。使用无远处复发生存期（DRFS）来优化临界值可以提高预后价值。根据多基因检测结果调整临界值后，低风险或低复发评分（≤21）估计的阳性预测值高于90%。平均而言，23%的病例在调整后得到了不同的风险评估结果。虽然通过多基因检测调整的临界值与通过生存情况优化的临界值不完全相同，但最佳模型（Magee方程1）的调整值（17.1和23.8）与优化值（17.5和24.5）接近。在所有评估模型中，Magee方程2是唯一不包含Ki67的模型，其预后价值最低。按照圣加仑共识建议，以20%作为Ki67的临界值，我们可以明确界定管腔A型癌症。
有必要调整基于IHC的预后模型的临界值以符合目的。如果估计风险明显高或低，在考虑成本的情况下，省略多基因检测可能是合理的。
