Monitoring the therapeutic response of locally advanced breast cancer patients: sequential in vivo proton MR spectroscopy study.

PURPOSE: To evaluate the use of the water-to-fat (W-F) value obtained from in vivo proton ((1)H) MR spectroscopy (MRS) as a response indicator of cytologically confirmed patients with locally advanced breast cancer (LABC), and to monitor the therapeutic response of such patients to neoadjuvant chemotherapy (NACT).
MATERIALS AND METHODS: Serial (1)H MR spectra were recorded both before and after the completion of chemotherapy in 33 LABC patients (with infiltrating ductal carcinoma (IDC)) at 1.5T. In addition, spectra from normal breast tissues of 28 healthy volunteers were recorded.
RESULTS: Malignant breast tissues showed elevated W-F values compared to normal breast tissues of controls. Statistically significant higher pretherapy W-F value (P < 0.01) was observed in patients compared to controls. In patients who received NACT resulting in the reduction of the primary tumor size, the W-F value showed a decrease that was statistically significant (P < 0.01). Analysis of the MR data further indicates that the W-F value had no correlation with the menstrual status of the patients. A comparison of pretherapy W-F value with pretherapy tumor volume showed a fair correlation (P = 0.05), while the posttherapy W-F value showed no such correlation with the posttherapy tumor volume.
CONCLUSION: This study demonstrates that simple, conventional in vivo (1)H MRS is a useful technique for monitoring the therapeutic response of breast cancer patients. The observed trend in the reduction of W-F value provides a noninvasive response indicator to monitor the clinical outcome of locally advanced breast cancer patients to NACT.