Radiological adjacent organ invasion in resectable left-sided pancreatic cancer indicates worse prognosis and may alter treatment strategies.

• Patients with adjacent organ invasion had median survival of 25.9 months versus 67.2 months for those without (p < 0.001).
• Elevated CA19-9 levels (≥279 U/ml) and positive peritoneal cytology were significantly more common in the invasion group.

Consider RAOI a marker for borderline resectable disease requiring intensive multimodal therapies.

• Even among those with negative cytology results, overall survival was lower in the invasion group (33.5 vs. 71.9 months, p = 0.001).