Dynamic Contrast-enhanced and Diffusion-weighted Magnetic Resonance Imaging for Response Evaluation After Single-Dose Ablative Neoadjuvant Partial Breast Irradiation
Vasmel, Jeanine E., Groot Koerkamp, Maureen L., Mandija, Stefano, Veldhuis, Wouter B., Moman, Maaike R., Froeling, Martijn, van der Velden, Bas H.M., Charaghvandi, Ramona K., Vreuls, Celien P.H., van Diest, Paul J., van Leeuwen, A. M.Gijs, van Gorp, Joost, Philippens, Marielle E.P., van Asselen, Bram, Lagendijk, Jan J.W., Verkooijen, Helena M., van den Bongard, H. J.G.Desirée, Houweling, Antonetta C.
DOI: https://doi.org/10.1016/j.adro.2021.100854
Advances in Radiation Oncology 7 (2), p. 1-11
Abstract
Purpose: We aimed to evaluate changes in dynamic contrast-enhanced (DCE) and diffusion-weighted (DW) magnetic resonance imaging (MRI) scans acquired before and after single-dose ablative neoadjuvant partial breast irradiation (NA-PBI), and explore the relation between semiquantitative MRI parameters and radiologic and pathologic responses.
Methods and Materials: We analyzed 3.0T DCE and DW-MRI of 36 patients with low-risk breast cancer who were treated with single-dose NA-PBI, followed by breast-conserving surgery 6 or 8 months later. MRI was acquired before NA-PBI and 1 week, 2, 4, and 6 months after NA-PBI. Breast radiologists assessed the radiologic response and breast pathologists scored the pathologic response after surgery. Patients were grouped as either pathologic responders or nonresponders (<10% vs ≥10% residual tumor cells). The semiquantitative MRI parameters evaluated were time to enhancement (TTE), 1-minute relative enhancement (RE 1min), percentage of enhancing voxels (%EV), distribution of washout curve types, and apparent diffusion coefficient (ADC).
Results: In general, the enhancement increased 1 week after NA-PBI (baseline vs 1 week median - TTE: 15s vs 10s; RE 1min: 161% vs 197%; %EV: 47% vs 67%) and decreased from 2 months onward (6 months median - TTE: 25s; RE 1min: 86%; %EV: 12%). Median ADC increased from 0.83 × 10 -3 mm 2/s at baseline to 1.28 × 10 -3 mm 2/s at 6 months. TTE, RE 1min, and %EV showed the most potential to differentiate between radiologic responses, and TTE, RE 1min, and ADC between pathologic responses.
Conclusions: Semiquantitative analyses of DCE and DW-MRI showed changes in relative enhancement and ADC 1 week after NA-PBI, indicating acute inflammation, followed by changes indicating tumor regression from 2 to 6 months after radiation therapy. A relation between the MRI parameters and radiologic and pathologic responses could not be proven in this exploratory study.