Eighteen RCTs were included for review (n=1,929).
Local Recurrence (17 studies n= 1,700): Adjuvant chemotherapy was associated with a significant reduction in the risk of local recurrence compared to localised treatment alone when all studies were combined (OR 0.73, 95% CI 0.56 to 0.94, p=0.02, NNT=25; 17 studies, n=1,700). There was no evidence of significant heterogeneity. However, there was no significant effect when studies of doxorubicin therapy alone and doxorubicin therapy combined with ifosfamide were analysed separately.
Distant and Overall Recurrence (18 studies n=1,747): Both doxorubicin alone (OR 0.69, 95% CI 0.56 to 0.86, p=0.001; 13 studies, n=1,338) and doxorubicin combined with ifosfamide (OR 0.61, 95% CI 0.41 to 0.92, p=0.02; five studies, n=409) were associated with a significant reduction in the risk of distant and overall recurrence. This effect remained when all studies were combined (distant recurrence OR 0.67, 95% CI 0.56 to 0.82, p=0.0001; 18 studies, n=1,747). There was no evidence of significant heterogeneity. The NNT for all studies was 12 for distant recurrence and 10 for overall recurrence.
Survival (18 studies, n=1,929): Doxorubicin combined with ifosfamide was associated with a significant reduction in mortality (HR 0.56, 95% CI 0.36 to 0.86, p=0.01; five studies, n=414). Doxorubicin alone did not significantly change the risk of mortality. The NNT for all studies combined was 17. There was no evidence of significant heterogeneity.