Objective: To determine whether breast cancer staging differs between high-resolution (HR) and standard-resolution (SR) PET/computed tomography acquisition.
Patients and methods: This retrospective study included 39 women with breast cancer referred for staging. Images were assessed for the number of primary breast lesions with the corresponding size and the average maximum standardized uptake value (SUVmax), the anatomical site of fluorine-18-fluorodeoxyglucose-avid lymph nodes (LNs) with their SUVmax, and the number and type (lytic/blastic) of metastatic bone lesions.
Results: On HR, 42 breast tumor lesions with a size range of 0.30 cm up to 12.00 cm were detected versus 34 breast tumor lesions on SR. One hundred and forty-one versus 90 axillary LNs were detected on HR versus SR, respectively. Pathology reports were available for 60 axillary LNs out of the total 141 identified on HR. Rates for HR versus SR sensitivity, true positivity, false positivity, and false negativity are as follows: 92 versus 75%, 92 versus 75%, 2 versus 0%, and 7 versus 25%. The higher detection rate of axillary LN on HR was significant (P<0.001), but not the number of nodes detected (P=0.091). SUVmax for breast tumor lesions (P=0.225) and axillary LNs (P=0.134) were not significant. Three (8%) patients had a change in staging and management.
Conclusion: HR detected primary breast lesions and metastatic LNs missed on SR, which led to change in staging and management. In addition, HR images provided higher SUVmax, which enabled a more comfortable localization, especially when SR presented borderline values. Finally, HR images decreased the number of gray zone lesions, especially in axillary LN detection.