CECT or MRI Surveillance Legend:

Primary
1: No evidence of recurrence: routine surveillance
2: Low suspicion 
a) Superficial abnormality (skin, mucosal surface): direct visual inspection 
b) Ill-defined deep abnormality: short interval follow-up*or PET 

3: High suspicion (new or enlarging discrete nodule/ mass): biopsy 
4: Definitive recurrence (path proven, clinical or definitive imaging progression): no biopsy needed
 
Nodes
1: No evidence of recurrence: routine surveillance
2: Low suspicion: (enlarging lymph node without morphologically abnormal features): short interval follow-up or PET
3: High suspicion (new or enlarging lymph node with morphologically abnormal features): biopsy if clinically needed
4: Definitive recurrence (path proven, clinical or definitive imaging progression): no biopsy needed

*short interval follow- up: 3 months at our institution