To analyze the relationship between the clinicopathological characteristics of invasive breast ductal carcinoma patients and the uptake of ⁹⁹Tc^m-methoxyisobutylisonitrile (MIBI) on breast-specific gamma imaging (BSGI).

We retrospectively analyzed the clinical data of 244 patients with invasive breast ductal carcinoma who underwent BSGI in the Weihai Municipal Hospital from March 2014 to March 2018, with no neoadjuvant therapy and biopsy and no distant metastasis before surgery. The BSGI data of all patients were analyzed, and the ratio of radioactive count in tumor to radioactive count in normal tissue (T/N) was calculated to assess the uptake of ⁹⁹Tc^m-MIBI in tumor. With skewed distribution, T/N was expressed as M(P₂₅-P₇₅). Wilcoxon rank sum test was used to analyze the relationship between the clinicopathological characteristics and T/N, and the multiple linear regression model was used to analyze the effect of clinicopathological characteristics on T/N.

In all 244 patients, T/N on BSGI ranged from 1.0 to 7.5. The results of Wilcoxon rank sum test showed that T/N was correlated with T stage, N stage, histological grade and Ki67 expression (Z=-6.852, 5.198, -3.931, P<0.001; Z=-3.059, P=0.002), but not correlated with ER, PR, HER-2, P53, EGFR expression and triple negative breast cancer (Z=-0.730, -1.526, -1.137, -1.175, -1.224, -1.556, P>0.050). The multiple linear regression analysis showed that T stage and N stage were influencing factors of T/N (t= 5.100, 95%CI: 0.414-0.935, P<0.001; t=2.819, 95%CI: 0.118-0.668, P=0.005).

The T stage and N stage of invasive breast ductal carcinoma may affect the uptake of ⁹⁹Tc^m-MIBI on BSGI. Therefore, using BSGI, T/N can be measured preoperatively to evaluate the malignancy of tumors.