A low total lesion glycolysis value in the primary breast tumor and a low metabolic tumor volume in the axillary lymph nodes, both measured on pretreatment PET/CT scans, were independently associated with achieving a pathological complete response after neoadjuvant chemotherapy in patients with hormone receptor-positive, HER2-negative breast cancer, according to a retrospective study published in BMC Cancer.
The parameters examined were the maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of both the primary breast tumor and the axillary lymph nodes.
The researchers analyzed records from 137 patients diagnosed with axillary lymph node-positive, HR-positive/HER2-negative breast cancer who received neoadjuvant chemotherapy between February 2020 and January 2025. Metabolic values for the breast tumor and the axillary nodes were recorded before treatment began. Threshold values best separating patients who achieved a pathological complete response from those who did not were determined using ROC curve analysis, and logistic regression was used to identify independent predictors.
A pathological complete response was observed in 19.0 percent of the cohort, corresponding to 26 of the 137 patients. In univariate logistic regression analysis, several factors were significantly associated with achieving this outcome: grade 3 tumors, Ki-67 of at least 20 percent, breast SUVmax below 14.25, breast MTV below 15.55, breast TLG below 73.32, axillary SUVmax below 4.55, axillary MTV below 14.32 and axillary TLG below 45.45.
When these variables were entered into a multivariate logistic regression model, only two remained independent predictors of pathological complete response: a breast TLG below 73.32 and an axillary MTV below 14.32. Patients whose pretreatment scans showed lower values on these volumetric measures were more likely to achieve a complete pathological response to neoadjuvant chemotherapy.
The findings suggest that, in this patient group, the size and burden of metabolically active disease before treatment, rather than peak uptake alone, carried the strongest predictive information.
The authors conclude that pretreatment volumetric metabolic parameters obtained from 18F-FDG PET/CT may provide clinically useful predictive information in HR-positive/HER2-negative locally advanced breast cancer, with low breast TLG and low axillary MTV independently associated with an increased likelihood of achieving a pathological complete response after neoadjuvant chemotherapy.
Several caveats apply to these results. The study identifies associations between imaging measurements and response; it does not establish that the metabolic parameters cause the differing outcomes, and the reported cutoff values reflect this specific dataset. The article was published as an open-access research paper, with the shared version subject to further editorial processing before the final version of record.
Subject of Research: Predicting pathological complete response in HR-positive/HER2-negative breast cancer using pretreatment PET/CT metabolic parameters
Article Title: Low baseline breast TLG and axillary MTV independently predict pathological complete response in HR-positive/HER2-negative breast cancer
Article References: Akar, Z., Bozkurt, H., Saray, S., Kadıoğlu, A., Erol, Z., Nihal Aksoy, A., & İriağaç, Y. (2026). Low baseline breast TLG and axillary MTV independently predict pathological complete response in HR-positive/HER2-negative breast cancer. BMC Cancer. https://doi.org/10.1186/s12885-026-17192-8
Image Credits: AI Generated
DOI: 10.1186/s12885-026-17192-8
Keywords: breast cancer, PET/CT, neoadjuvant chemotherapy, pathological complete response, total lesion glycolysis, metabolic tumor volume, HR-positive, HER2-negative, axillary lymph nodes, SUVmax, predictive biomarkers, retrospective study
News Source: Nathaniel Bowman. (October 29, 2026). PET scans before chemotherapy may predict response in breast cancer patients. Scienmag.
