A pilot study to assess the feasibility of evaluation of markers of response to chemotherapy at one day & 21 days after first cycle of chemotherapy in carcinoma of breast: a prospective non-randomized observational study

BACKGROUND: Interest in translational studies aimed at investigating biologic markers in predicting response to primary chemotherapy (PCT) in breast cancer has progressively increased. We conducted a pilot study to evaluate feasibility of evaluating biomarkers of response to PCT at one & 21 days after first cycle. METHODS: Adult, non-pregnant, non-lactating women with histologically confirmed infiltrating duct carcinoma underwent serial core biopsies after first cycle of PCT and these were scored for Ki-67, Bcl-2 and Caspase-3 using immunohistochemistry. RESULTS: We recruited 30 patients with a mean age of 51 years. We were successful 95.6% times in performing a core biopsy and of these 84.6% had adequate tissue in the cores harvested. After a mean of 4 cycles of PCT, 26 patients underwent surgery and good response was noted in 9 patients (30%) using Miller-Payne criteria. There was a trend noted in all markers, which appeared different in those with good response and poor response. Good responders had significantly higher Ki-67 and significantly lower Bcl-2 at baseline and a significant decrease in Ki-67 and Caspase-3 at 21 days after the first chemotherapy. CONCLUSION: We report a detectable change in biomarkers as early as 24–48 hours after the first chemotherapy along with a definite trend in change that can possibly be used to predict response to chemotherapy in an individual patient. The statistical significance and clinical utility of such changes needs to be evaluated and confirmed in larger trials.