Three serum markers, TPS, CA 15.3 and CEA, were used to monitor the response to treatment of 20 patients with metastatic breast cancer. At the time of the first evidence of metastases or at the time of progression of known metastatic disease, 84% of TPS values were above the reference limit, as compared to 74% for CA 15.3 and 84% forCEA. If the treatment instituted was effective, 60% of TPS values showed an early (within 2 or 3 weeks after commencement or change of therapy) reduction in level against only 27% of CA 15.3 and 27% of CEA levels. This suggests that TPS provides a more sensitive and earlier predictor of therapeutic response. In patients with clinical evidence of further progression of disease while on therapy , 86% ofTPS values showed persistent elevation or increase, as compared to 71 % of CA 15.3 levels and only 36% ofCEA levels. It was also noted in these patients that TPS values rose earlier than either CA 15.3 or CEA. This indicates that TPS is a more reliable predictor of response to treatment than the other two markers. In addition, we found that, at the time of presentation, in women who had visceral metastases (liver, lung, or brain alone or in combination), 87% ofTPS values were raised, as compared to 80% of CA 15.3 and 73% of CEA values. In women who had bone and soft tissue metastases at presentation, 75% ofTPS values were elevated, against 50% ofCA 15.3 and 75% of CEA values. We also noted that in patients without raised TPS levels, the sites of subsequent disease progression were limited to bones, regional lymph nodes, skin and soft tissues.
Early, On-Treatment Levels and Dynamic Changes of Genomic Instability in Circulating Tumor DNA Predict Response to Treatment and Outcome in Metastatic Breast Cancer Patients
