Assessment of cardiorespiratory dysfunction in patients with breast carcinoma receiving neo-adjuvant chemotherapy using cardiopulmonary exercise testing, and to evaluate their early post-operative trajectory with patients with breast carcinoma posted for upfront surgery: A prospective observational study.
Authors: Gupta Mahima , Mishra Seema , Garg Rakesh , Gupta Nishkarsh , JeeBharti Sachidanand , Kumar Vinod , Batra Atul , Gogia Ajay , Pandey Shivam , Deo S.V.S. , Bhatnagar Sushma 
Published: June 2023

e12580 Background: Patients having locally advanced breast cancer, are planned for breast conservation therapy (BCT). BCT involves breast conservation surgery (BCS) followed by adjuvant radiotherapy. Patients not suitable for upfront BCS are considered for neoadjuvant therapy (NACT) followed by BCS. Chemotherapy induced cardiac dysfunction (CRCD) such as cardiomyocyte injury and decrease in left ventricular ejection fraction (LVEF) is well documented. Currently, there is no objective method to detect early onset cardiac dysfunction. Therefore, we conducted this prospective observational pilot study to determine the role of Cardiopulmonary exercise testing (CPEX) in detecting cardiopulmonary dysfunction in patients receiving NACT. Methods: After the approval from the Institutional Ethics Committee, with informed consent, patients attending breast cancer clinic were enrolled. Group A- receiving NACT, followed by surgery and Group B - posted for upfront surgery. At our institute, there are fixed protocols for deciding the patient for NACT Vs upfront surgery, which were followed while patient recruitment. The procedure for CPEX was explained to eligible patients. CPEX was performed on the patients before the start of chemotherapy and 6 weeks after the completion of neoadjuvant chemotherapy (NACT) as per ATS/ACCP protocol. Results: In total 30 patients were analysed. In Group A patients, there was a significant decrease in the mean VO2 peak/kg values post NACT (14.8ml/kg/min) in contrast to the beginning of NACT (15.6 ml/kg/min) with a (p = 0.03) with reduction in oxygen pulse (VO2/HR), which is a surrogate marker for stroke volume (SV), pre NACT value as (6.3 ml/beat) and post NACT value as (5.4 ml/beat) with a (p= 0.000). In Group B patients, the presurgery and postsurgery values for the patients for the parameters – anaerobic threshold [VO2 (AT)] & oxygen pulse [VO2/HR (AT)], were lower post surgery p < 0.001 & 0.03 respectively, which can be due to cardiovascular or respiratory dysfunction. Since the decrease in VO2/AT was more significant as compared to VO2/HR, along with the significant reduction in pulmonary parameters – Minute Ventilation [VE (max), p = 0.01], the decreased anaerobic threshold of the patients can be attributed to be pulmonary in origin rather than cardiac, probably post operative atelectasis after general anaesthesia lasting for 6 weeks, the timeline within which we conducted the testing of our patients post surgery. Conclusions: CPEX can be a useful modality to detect subtle and early cardiovascular and pulmonary adverse effects caused due to NACT. In future, CPEX might prove as a gold standard for assessment of changes in the cardiopulmonary parameters at an early stage.