Correlation of clinico-pathological outcomes with changes in IHC4 status after neo-adjuvant chemotherapy (NACT) for locally advanced breast cancers: Do pre NACT ER/PR status act as better prognosticators?
1Tata Medical Center, Kolkata, West bengal, India
Differential expression of 4 immumohistochemical markers ( IHC-4) i.e, oestrogen receptor (ER), progesterone receptor (PR), Her-2 receptor and Ki-67 in breast cancer is used as surrogate to molecular classification. The correlation of changes in IHC-4 following neoadjuvant chemotherapy (NACT) , to tumour pathological response rates (pCR) and disease relapse rates could lead to better understanding of tumour behaviour.
Pre and post NACT IHC 4 status was analysed in 156 breast cancer patients. Response to chemotherapy was reported as per CAP recommendations 2009. Associations between IHC-4 before and after NACT were evaluated by using the McNemar test for ER, PR, HER-2 and a paired Student t-test for the Ki-67. Associations between the pCR to other categorical variables were assessed by using the chi-square tests or Fisher exact tests. Associations between pCR and the Ki-67 index were performed using the independent Student t-test. Kaplan-Myer plots were analysed to obtain relapse free survival (RFS).
The median age was 48years. 25.3 % patients had pCR . Grade 3 tumours had a higher pCR (27.4%). ER and PR both positive tumours had the lowest (14.3%) pCR compared to tumours with both ER and PR negative (29% ) or those with either ER or PR positive (38.6%). PR positivity was significantly associated with less likelihood of pCR (15% vs 34%). The pCR rate was lowest for LA subtype (13.68%) compared to 24.36%, 26.31%, 33.33% for LB, HE and TN subtypes respectively. There were significant reduction in expression of ER receptors and Ki-67 index post NACT. RFS of patients in whom the hormonal status changed from positive to negative was better compared to those who changed from negative to positive.
Changes in IHC 4 occur post NACT. pCR rates are lower in PR positive tumours and pre, not post, NACT HR status seemed to prognosticate RFS better.