Southwestern Oncology Group pretreatment risk criteria as predictive or prognostic factors in acute myeloid leukemia

Acute myeloid leukemia (AML) is a clonal hematological malignant condition and the implications of pretreatment risk criteria as predictive or prognostic factors are constantly under evaluation. With this study, the authors' intent was to characterize AML patients and to evaluate the clinical outcome associated with Southwestern Oncology Group (SWOG) coding pretreatment risk criteria/cytogenetic score. Between 2002 and 2010, 225 patients were diagnosed with AML at the Portuguese Institute of Oncology (Porto, Portugal). From this patient group, 128 patients aged <65 years were selected. The patients were treated using a combination of cytarabine and anthracycline, with the addition of cyclosporine when bone marrow dysplasia was observed. A median survival of 24 months was observed in this group. The patients were divided in subgroups according to the SWOG pretreatment risk criteria. We observed a statistically significant association of non-favorable SWOG coding with female gender [P=0.025; risk ratio (RR)=3.632, 95% confidence interval (CI): 1.113-11.852], indication for allogeneic bone marrow transplantation (P=0.023, RR=1.317, 95% CI: 1.184-1.465), complete response achievement (P=0.013, RR=1.385, 95% CI: 11.232-1.556) and relapse (P=0.048, RR=3.181, 95% CI: 10.966-10.478). Furthermore, SWOG pretreatment risk criteria also significantly affected global overall survival (OS; P=0.003) and OS at 5 years (P=0.001). A multivariate Cox regression analysis supported response to induction therapy (3-year OS: P=0.011, RR=0.385, 95% CI: 10.184-0.806; 5-year OS: P=0.012, RR=0.388, 95% CI: 10.597-1.994), consolidation (3-year OS: P=0.005, RR=0.328, 95% CI: 0.150-0.720; 5-year OS: P=0.002, RR=0.308, 95% CI: 0.144-0.657) and the diagnosis of therapy-related aml (3-year OS: P=0.016, RR=2.756, 95% CI: 0.486-1.281; 5-year OS: P=0.031, RR=2.369, 95% CI: 1.081-5.189) as prognostic factors, but this was not confirmed for SWOG pretreatment risk criteria. Therefore, we concluded that the reproducibility of the application of the SWOG pretreatment risk criteria may not be available as a prognostic factor in every acute leukemia population. However, its application as a predictive factor of response has been confirmed in our population.