The additive role of 1H-magnetic resonance spectroscopic imaging to ensure pathological complete response after neoadjuvant chemotherapy in breast cancer patients

Purpose
To assess the role of ¹H-magnetic resonance spectroscopy (¹H-MRS) in the confirmation of pathological complete response after neoadjuvant chemotherapy in breast cancer.

Material and methods
Forty-seven cases (53.72 ± 8.53 years) were evaluated using magnetic resonance imaging (MRI) and ¹H-MRS with choline (Cho) signal-to-noise ratio (SNR) measured followed by histopathology and ROC analyses.

Results
Twelve patients had complete response, and 35 patients had residual disease. Mean age was 53.72 ± 8.53 years. The mean tumour size before neoadjuvant chemotherapy (NAC) was 4.21 ± 0.99 cm and after NAC was 0.9 ± 0.44 cm.Positive total choline signal (tCho) was detected in all cases. The mean Cho SNR before NAC was 9.53 ± 1.7 and after NAC was 2.53 ± 1.3. The Cho SNR cut-off point differentiating between pathologic complete response (pCR) and the non pCR was 1.95. Dynamic MRI showed 83.3% sensitivity, 65.7% specificity, 45.5% positive predictive value, 92.0% negative predictive value, and 70.2% diagnostic accuracy. Combined evaluation done by using the dynamic MRI and ¹H-MRS showed 91.5% diagnostic accuracy with 75.0% sensitivity, 97.1% specificity, 75% positive predictive value, and 91.9% negative predictive value. ROC curves of Cho SNR showed statistically significant differences between non pCR and pCR with AUC was 0.955, 82.9% sensitivity, 91.7% specificity, 96.7% positive predictive value, 64.7% negative predictive value, and 85.11% diagnostic accuracy.

Conclusions
¹H-MRS improves the diagnostic accuracy in the prediction of the pCR after NAC.