In patients with breast cancer the assessment of the response to neoadjuvant chemotherapy (NAQ) is very important in order to plan the surgical treatment. Magnetic Resonance Imaging (MRI) is accepted as the best method to predict pathological response to NAQ. However, previous studies suggested that the accuracy of MRI in this situation can be altered by different factors. Initially NAQ was used to improve the surgical options of the patients, in recent years its used has been extended to patients with tumours with immunofenotypes that have a high probability of achieving pathological complete response (pCR), which is associated with better prognosis in triple negative (TN) and HER2 (+) subtypes. This retrospective study included 186 breast cancer patients treated with NAQ between January 2006 and June 2013 at Hospital del Mar. All patients underwent a baseline MRI and after NAQ. Luminal tumours predominated in our series (21% Luminal A and 33.3% Luminal B-HER2[-]). A pCR was achieved in 17.4% patients, 66.7% in HER(+) tumours, the highest, and 0% in Luminal A tumours, the lowest. The main predictors of pCR were Hormonal Receptors (RH) and HER2 status. We observed a good correlation between residual tumour size evaluated by MRI and tumour size evaluated by pathology, with a mean discrepancy of 11.6 mm. The size discrepancy was smaller in TN tumours, of 3.2 mm versus 15.4 mm in Luminal A tumors, where we find the greatest discrepancy. Initial tumor size and HER2 status were significantly correlated with the accuracy of MRI to asses residual tumour size. The overall sensitivity, specificity, positive predictive value and negative predictive value to predict pCR by using MRI were 75.8%, 79.7%, 44.6% and 77.75%. The accuracy of the MRI to detect pCR was superior in the breast that in the axilla. The accuracy of the MRI to detect pCR was influenced by the basal value of ki 67. The immunofenotype where the MRI better evaluated the response was the TN. We did not identified any subgroup where the reliability of MRI was 100% and where it could be considered to eradicate the surgical treatment. Patients who achieved pCR had a higher relapsing free survival rate. In our cohort, patients with most relapses were those with TN tumors, especially those that did not reach pCR.
|Date of Award||28 Sept 2017|
|Supervisor||Sònia Servitja-Tormo (Director), Ignacio Ramon Tusquets Trias De Bes (Director) & Adolfo Diez Perez (Tutor)|