ERBB2 and breast cancer: Additionally, in the NET setting, tools such as the modified Preoperative Endocrine Prognostic Index (PEPI) score are increasingly used to guide treatment decisions given that PCR is a less reliable surrogate for long-term outcomes in HR+/HER2– breast cancer.31–33 This reasoning may explain such a discrepancy in the care observed in this study compared with the current guidelines.