Correlation of maximum standardized uptake values in ¹⁸F-Fluorodeoxyglucose Positron Emission Tomography-computed tomography scan with immunohistochemistry and other prognostic factors in breast cancer

The objective of this study was to correlate maximum standardized uptake value (SUV_max) with different immunohistochemical subtypes of breast cancer and other prognostic factors in breast cancer. This was a retrospective study including 219 consecutive patients undergoing whole-body fluorodeoxyglucose positron emission tomography/computed tomography scan for the staging of breast cancer. Out of 219 patients, two were male and 217 were female; age ranged from 26 to 85 years with mean age of 54 years. On histopathological examination (HPE), 197 patients were of invasive ductal carcinoma type and two of lobular type. Histopathological grades, immunohistochemistry (IHC) types, and ki-67 values were compared with SUV_max values. The mean SUV_max of the population was 11.39 (±6.05). The mean SUV_max in different HPE grades was Grade 1 = 6.81 ± 5.6, Grade 2 = 11.4 ± 6.12, and Grade 3 = 13.14 ± 5. The mean SUV_max values in different IHC types were Luminal A = 7.75 ± 4.2, Luminal B = 10.01 ± 5.3, triple negative = 15.26 ± 5.6, and HER2 enriched = 11.27 ± 5.2. The mean SUV_max in high ki-67 patients was 11.97 ± 5.85 compared with 7.25 ± 3.43 patients with low ki-67. Univariate analysis showed significant difference in SUV_max in patients with different grades (P= 0.013), hormone receptor positivity (P≤ 0.001), ki-67 (P< 0.001), and axillary lymph node positivity (P≤ 0.001). In multivariate regression analysis, there was significantly higher SUV_max value in triple-negative patients after correcting for tumor size, ki-67 value, axillary lymph node status, and grade of tumor. High SUV_max values were noted in high-grade, high ki-67, triple-negative, and axillary lymph node positive tumors. (author)