Laura Martincich MD, Presenter: Consultant, General Electric Company Speaker, Bracco Group

Valentina Lolli MD, Abstract Co-Author: Nothing to Disclose

Silvia Carabalona MD, Abstract Co-Author: Nothing to Disclose

Valentina Rossi, Abstract Co-Author: Nothing to Disclose

Filippo Montemurro MD, Abstract Co-Author: Nothing to Disclose

Daniele Regge MD, Abstract Co-Author: Consultant, im3D SpA

Previous preliminary studies suggested that DWI may assess the tumor response in patients with Locally Advanced Breast Cancer (LABC) undergoing primary medical treatments. The aim of the study was to evaluate in a larger series if the Apparent Diffusion Coefficient (ADC) value may early predict tumor response in patients with LABC undergoing neoadjuvant chemotherapy (NCT).

50 patients with monolateral LABC (stage II with T>3cm or IIIA/B/C) were treated by taxane-based NCT followed by surgery. MR examinations were conducted before, during (after two cycles) and after NCT using 1.5T scanner and 8-channel coil. DWI was performed by an EPI sequence on axial plane (b-value 0 and 900 s/mm2; slice thickness 4mm; acquisition time 80s). ADC value was calculated by tracing a region of interest within the lesion margins (Functool software; GEHC). Pathological tumor response was defined according to Smith scheme (JCO 2002): patients were classified as Responder if grade 5 (pathological complete response) or 4 (small clustered residual cancer cells) were obtained and as Non-Responder if grades 1-3 were found. Variation in ADC value after two cycles of NCT was evaluated and it was correlated with pathological response.

At pathology 12 patients were defined as Responders, while 38 as Non-Responders. Before NCT the mean ADC value did not significantly differ between Responders (1,11±0,14x10-3 mm2/s; range 0,9-1,43) and Non-Responders (1,06±0,25x10-3 mm2/s; range 0,6-2,08). After two cycles of NCT, the mean ADC value changed from 1,11±0,14x10-3 mm2/s to 1,48±0,2 x10-3 mm2/s (range 1,03-1,9) in the Responders (p<0,0001) and from 1,06±0,25 x10-3 mm2/s to only 1,19±0,28x10-3 mm2/s (range 0,7-2,03) in the Non-Responders (p=0,03). Variation of mean ADC value was significantly different between the two groups (p=0,04).

Variation of ADC value during NCT significantly differs between Responder and Non Responder patients. DWI could be proposed as non-invasive tool to early monitor tumor response in patients undergoing NCT. In addition, it does not require contrast media administration with consequent impact on both safety and costs.

From the oncological point of view it is important to early identify which patients will benefit from medical treatment in order to avoid unnecessary potentially toxic therapies.

Martincich, L, Lolli, V, Carabalona, S, Rossi, V, Montemurro, F, Regge, D, Role of Diffusion-weighted Imaging (DWI) in the Early Assessment of Tumor Response in Patients with Locally Advanced Breast Cancer Undergoing Neoadjuvant Chemotherapy.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11007187.html