Comparison 1. Interferon versus observation alone.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Overall survival	2	370	Hazard Ratio (Random, 95% CI)	1.14 [0.84, 1.55]
2 Progression‐Free Survival	2	370	Hazard Ratio (Random, 95% CI)	0.99 [0.79, 1.24]
3 Adverse event (flu‐like symptoms)	1	293	Risk Ratio (M‐H, Random, 95% CI)	2.25 [1.73, 2.91]
4 Adverse event (fatigue)	1	293	Risk Ratio (M‐H, Random, 95% CI)	1.54 [1.27, 1.88]
5 Adverse event (nausea/ vomiting)	1	293	Risk Ratio (M‐H, Random, 95% CI)	1.21 [0.91, 1.62]