Team dynamics significantly affect patient outcomes in complex surgical oncology.

• Five resident-led teams had unacceptably high adverse event rates (6.9% to 22.3%).
• Thirteen teams had longer-than-expected hospital stays (+0.4 to +3.5 days), while seven teams had shorter stays (-1.1 to -0.7 days).

Effective performance benchmarking can pinpoint teams needing additional supervision.

• Three teams had higher-than-expected 30-day readmission rates (4.9% to 6.8%).