Details of the study results
For their study, Janni and colleagues conducted a comprehensive pooled analysis of globally available data. They identified 4079 metastatic breast cancer patients who had undergone baseline and follow-up CTC measurements (at least one, at a median of 29 days later) in previous clinical trials.
The investigators analyzed changes in CTC levels between baseline and follow-up to determine whether they were associated with OS.
Of the 2961 patients who were CTC-positive at baseline, 1855 remained CTC-positive after treatment was initiated (positive/positive), and 1106 patients had converted to CTC-negative status (positive/negative).
Of the 1118 patients who were CTC-negative at baseline, 813 remained CTC-negative (negative/negative), and 305 had become CTC-positive (negative/positive).
As noted above, median OS was greatest for patients who were negative/negative (47 months), followed by patients who were positive/negative (32.2 months), negative/positive (29.6 months), and positive/positive (17.8 months).
Hazard ratios in which the reference group was negative/negative were 1.52 for the positive/negative group, 1.74 for the negative/positive group, and 3.15 for the positive/positive group (P < .0001 for all groups).
These CTC dynamics were found across all breast cancer subtypes, said Janni.
“These data indicate that CTC dynamics can predict the trajectory of the disease a little more than four weeks after initiating treatment,” said Janni in the press statement. “This provides an advantage over conventional imaging methods and can help physicians determine very early on whether a treatment should be continued. It is also very reassuring that CTC dynamics predicted outcomes for all breast cancer subtypes.”
The study was supported by Menarini Silicon Biosystems, the makers of CellSearch, the CTC test used for all of the patients and studies in the meta-analysis. Janni received a research grant from Menarini Silicon Biosystems. Other study authors have financial ties to healthcare industries. Kaklamani has received consulting fees from Amgen, Eisai, Puma, Celldex, AstraZeneca, and Athenex; fees for non-CME services received directly from commercial interest or their agents from Pfizer, Celgene, Genentech, Genomic Health, Puma, Eisai, and Novartis; and has contracted research with Eisai.
This article first appeared on Medscape.com.