Emerging research suggests that magnetic resonance imaging (MRI) may offer significant utility in predicting the response of patients with triple-negative breast cancer (TNBC) to the combination of neoadjuvant chemotherapy and immunotherapy.
For the retrospective study, recently published in European Radiology, researchers reviewed pre-treatment and preoperative MRI data for 111 women with TNBC. The cohort was comprised of 59 patients (mean age of 43.8) who had neoadjuvant chemotherapy (NAC) and 52 patients (mean age of 46.1) who had NAC and immunotherapy (NACI), according to the study. The study authors noted that the pre-op MRI was obtained after initial treatment.
For the overall cohort, the researchers found that MRI offered an 82.5 percent sensitivity, a 72.9 percent specificity, an 80 percent positive predictive value (PPV) and a 78.3 percent accuracy rate in predicting pathological complete response (pCR).
However, MRI offered enhanced prognostic capabilities in the NACI group in comparison to the NAC cohort. For patients in the NACI group, the study authors noted that MRI offered a 26.4 percent higher sensitivity, an 11.6 percent higher PPV and an 11.8 percent higher accuracy rate for predicting pCR in contrast to the NAC group.
“The results demonstrated that the addition of immunotherapy to neoadjuvant chemotherapy enhanced the rates of rCR and pCR in patients with TNBC. The study showed that MRI presents a good diagnostic accuracy in predicting pathologic response in TNBC, regardless of the type of treatment,” wrote lead study author Soraia Quaranta Damiao, M.D., who is affiliated with the Department of Imaging at the A.C. Camargo Cancer Center in Sao Paulo, Brazil, and colleagues.
However, the researchers also noted that MRI offered a higher predictive specificity for pCR in the NAC cohort (77.4 percent vs. 64.7 percent for patients receiving NACI).
Three Key Takeaways
• MRI is a reasonably accurate predictor of pCR in TNBC overall. Across all patients, post-treatment MRI demonstrated good diagnostic performance for predicting pathological complete response, with an 82.5 percent sensitivity and a 78.3 percent overall accuracy.
• Predictive performance of MRI improves with immunotherapy. In patients receiving neoadjuvant chemotherapy plus immunotherapy (NACI), MRI showed substantially higher sensitivity, PPV, and accuracy for pCR prediction compared with chemotherapy alone, supporting its prognostic value in the immunotherapy era.
• Lower specificity in NACI warrants cautious interpretation. Reduced specificity in the NACI group likely reflects immune-related imaging changes (e.g., fibrosis, edema, necrosis) that can mimic residual disease, underscoring the need for careful MRI interpretation and correlation with pathology in these patients.
“ … The reduced specificity observed in the NACI group … may reflect immune-related effects such as fibrosis, peritumoral edema, or treatment-induced necrosis that can mimic residual disease on post-treatment imaging,” suggested Damiao and colleagues.
While noting recent research that suggests that immunotherapy does not affect the prognostic capability of MRI, even with abbreviated breast MRI protocols, to predict pCR in these patient population, the study authors pointed out that molecular subtype does play a significant role.
“Several studies have shown a better correlation between radiological and pathological response in TNBC than other subtypes,” added Damiao and colleagues.
Beyond the inherent limitations of a single-center retrospective study, the authors acknowledged the relatively small cohort size, heterogeneity with scanners and protocols, and possible patient selection bias with the exclusion of patients who didn’t have an available preoperative MRI.
