Connolly RM, et al. - Researchers investigated if pathologic complete response (pCR) to neoadjuvant pertuzumab and trastuzumab (PT) was predicted by early measurements of tumor maximum standardized uptake values corrected for lean body mass (SULmax) on [¹⁸F]fluorodeoxyglucose positron emission tomography/computed tomography in patients with stage II/III, estrogen receptor–negative, human epidermal growth factor receptor 2 (HER2)-positive breast cancer. Participants were given four cycles of neoadjuvant PT. At baseline and 15 days after PT initiation (C1D15), [¹⁸F]Fluorodeoxyglucose positron emission tomography/computed tomography was performed. They tested the null hypothesis that the area under the curve of percentage of change in SULmax by C1D15 predicting pCR is less than or equal to 0.65, with a one-sided type I error rate of 10%. Findings revealed that response to four cycles of PT was predicted by early changes in SULmax. Once optimized, this quantitative imaging strategy may facilitate a more tailored approach to therapy in this setting.