Purpose: To identify the readily available prognostic factors most helpful in predicting survival and to construct and validate a prognostic index for metastatic breast cancer (MBC) patients.
Patients and methods: Data from 233 MBC patients, accrued on a multiinstitutional randomized phase III trial (Japan Clinical Oncology Group [JCOG] study 8808), were analyzed to identify significant prognostic factors and a prognostic index was constructed by incorporating these prognostic factors. For validation of the prognostic index, another data set from 315 consecutive MBC patients, who had been treated with standard anthracycline-containing regimens, was analyzed.
Results: In multivariate regression analyses, history of adjuvant chemotherapy (ADJCT) (P = .0005), presence of distant lymph nodes (DLNs) (P = .0117) and liver (HEP) (P = .0099) metastases, elevation of serum lactate dehydrogenase (LDH) (P < .0001), and shorter disease-free interval (DFI) (P < .0001) significantly contributed to poorer survival. The prognostic index was constructed as follows: Prognostic Index = ADJCT (not received = 0, received = 1) + DLNs (absent = 0, present = 1) + HEP (absent = 0, present = 1) + LDH (< or = one times normal = 0, > one times normal = 1) + DFI (> or = 24 months = 0, < 24 months = 2). With this prognostic index, patients could be stratified into three risk groups. The median survival times (MSTs) of low-, intermediate- and high-risk groups were 45.5, 24.6, and 10.6 months, respectively (P < .0001). This prognostic index was applied to the validation patients. The respective MSTs for each risk group were 49.6,22.8, and 10.0 months (P < .0001).
Conclusion: ADJCT, DLNs, HEP, LDH, and DFI were important prognostic factors for MBC patients. The prognostic index readily enables MBC patients to be stratified into three risk groups and is worth considering for future clinical trials.