E2447. Association of Tumor to Fibroglandular Enhancement Ratios with Breast Cancer Survival in Patients Undergoing Neoadjuvant Chemotherapy
Authors
Sohum Patel;
Geisel School of Medicine at Dartmouth
Dennis Dwan;
Beth Israel Deaconess Medical Center
Nasim Azizgolshani;
Columbia University Medical Center
Yasmin Kamal;
Brigham and Women's Hospital, Harvard Medical School
Judith Austin-Strohbehn;
Dartmouth-Hitchcock Medical Center
Roberta diFlorio-Alexander;
Dartmouth-Hitchcock Medical Center
Objective:
Neoadjuvant chemotherapy (NAC) is increasingly used in women with breast cancer; and patients with pathologic complete response (pCR) yield the greatest benefit. Unfortunately, only 40 - 60% of all women who undergo NAC have pCR. Therefore, women with a pathologic incomplete response (pIR) who are surgical candidates experience a delay in definitive loco-regional treatment. The expanded use of NAC, particularly in women with operable breast cancer, intensifies the need to identify techniques to predict NAC response and survival before treatment begins. Our aim was to compare treatment response and recurrence-free survival with enhancement ratios between the tumor and contralateral fibroglandular tissue (FGT) on dynamic contrast-enhanced breast MRI (DCE-MRI).
Materials and Methods:
We conducted an IRB-approved retrospective study of 105 women (mean age of 52 years) with invasive breast cancer: 35/105 triple negative, 49/105 ER positive, and 21/105 human epidermal growth factor 2-enriched who underwent DCE-MRI prior to administration of neoadjuvant chemotherapy. Two senior radiologists blinded to clinical data obtained equal-volume ROIs and signal intensity values within the tumor and contralateral breast fibroglandular tissue (FGT) on early (S1) and delayed (S2) enhanced sequences of preoperative breast DCE-MRI. Mean differences and ratios of enhancement within the tumor and contralateral FGT were calculated. Comparative statistics were used to compare NAC response and survival to differential enhancement in the tumor and contralateral FGT.
Results:
Among 105 patients, 47 (44%) of patients had pathologic complete response (pCR) and 59 (56%) had pathologic incomplete response (pIR) to NAC. Patients with pCR had a higher mean difference in signal intensity between the tumor and contralateral breast on both early and delayed enhanced sequences compared to patients with pIR [405 (pCR) and 305 (pIR), (p = 0.033) and 351 (pCR) and 241 (pIR), (p = 0.017) respectively]. The ratio of tumor signal intensity divided by contralateral breast parenchymal signal intensity was also found to be significantly different between the two groups; patients with pCR had a greater enhancement on both early and delayed sequences compared to patients with pIR (S1: p = 0.005 and S2: p = 0.002). The difference in signal intensity between tumor and contralateral breast on delayed (S2) phases was also found to be significantly associated with recurrence-free survival between patients with pCR and pIR. Specifically, lower mean differences between tumor and contralateral breast parenchyma were associated with a greater likelihood of death (p = 0.03).
Conclusion:
Higher differences and ratios in postcontrast signal intensity between the tumor and contralateral breast parenchyma are significantly associated with pCR and recurrence-free survival. These findings may reflect the interaction between tumor biology and patient-specific breast tissue that affects tumor behavior and individualized treatment response and survival.
