Fig. 4. Impact of clinical and pathological characteristics, ¹⁸F-FDG-PET/CT response and ctDNA detection on PFS (univariate analysis).

Blue boxes represent parameters that have a significant impact on PFS. Yellow boxes represent parameters which doesn’t have significant impact on PFS. Horizontal lines represent CI. X-axis represents HR. CI: 95% confidence interval, p: p value, HR: hazard ratio. ECOG = Eastern Cooperative Oncology Group performance status, ranging from 0 to 5, and indicating that the patient is at 0, fully active able to carry on all pre-disease performance without restriction; at 1,restricted in physically strenuous activity but ambulatory and able to carry out work of a light or sedentary nature; at 2, 2 - ambulatory and capable of all self-care but unable to carry out any work activities; up about more than 50% of waking hours; N metastasis = number of metastatic organ sites involved, Visceral meta = presence of visceral metastasis, N = no, Y = yes, N prior chemotherapies = number of prior chemotherapy regimens used for the treatment of advanced breast cancer, NSAI = non-steroidal aromatase inhibitor; sensitive is defined as relapse ≥2 years after the end of a NSAI in adjuvant setting or ≥ 6 months treatment in metastatic setting, Consist 25% = <25% homogenous decrease in maximum standardized uptake value (SUVmax) in all target lesions are considered as “non-responders”, Consist 15% = <15% homogenous decrease in maximum standardized uptake value (SUVmax) in all target lesions are considered as “non-responders”.