Discordance of Radiologic and Pathologic Complete Response in Patients with Triple-negative Breast Cancer Undergoing...

Area of Science:

• Oncology
• Radiology
• Immunotherapy

Background:

• Pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) is crucial for triple-negative breast cancer (TNBC) outcomes.
• Breast MRI and US assess NAC response but immunotherapy (IO) effects are unclear.

Purpose of the Study:

• To evaluate discordance between radiologic complete response (rCR) and pCR in TNBC patients.
• To assess the impact of IO on radiologic response assessment after NAC.

Main Methods:

• Retrospective cohort study (2013-2022) of 186 TNBC patients.
• Analyzed pre- and post-NAC MRI/US, correlating rCR with pCR.
• Used Cohen's kappa and Fischer's exact test to measure concordance and association with IO.

Main Results:

• pCR and MRI concordance decreased with IO (kappa=0.39 vs 0.60 without IO).
• pCR and US concordance was negligible with IO (kappa=0.05 vs 0.42 without IO).
• In patients without rCR on MRI, IO was associated with pCR (p=0.009), with a lower negative predictive value (NPV=50% with IO vs 84% without IO).

Conclusions:

• Neoadjuvant chemoimmunotherapy (NAC+IO) significantly reduces the NPV of post-NAC MRI in TNBC.
• MRI may overestimate treatment response in TNBC patients receiving IO, potentially due to immunotherapy-induced inflammation.
• Further research is needed to understand IO-related inflammatory changes affecting radiologic assessments.