1. How do you select target lesions according to RECIST 1.1 criteria?
Answer: → Select up to 5 lesions total (max 2 per organ) with longest diameter ≥10 mm (or ≥15 mm for lymph nodes) → Choose lesions that are measurable and representative of overall disease → Prioritize largest and most reproducible lesions → Document baseline measurements accurately.
2. What is the difference between measurable and non-measurable disease in RECIST 1.1?
Answer: → Measurable: Lesions with clear borders, ≥10 mm longest diameter (or ≥15 mm short axis for nodes) → Non-measurable: Lesions <10 mm, bone lesions, effusions, or inflammatory breast disease → Clearly document non-measurable disease in CRF for proper response assessment.
3. How do you calculate Sum of Diameters (SOD) in RECIST 1.1 and when do you use it?
Answer: → Measure longest diameter for non-nodal lesions and short axis for lymph nodes → Add all target lesion measurements to get SOD → Use SOD at baseline and every follow-up to calculate percentage change for response assessment.
4. A lymph node measures 12 mm at baseline and 14 mm at follow-up. How do you classify this in RECIST 1.1?
Answer: → Lymph nodes use short axis measurement → ≥15 mm is measurable target lesion → This node (14 mm) is non-target → Track as non-target lesion and note appearance or size change separately.
5. What constitutes Progressive Disease (PD) according to RECIST 1.1?
Answer: → ≥20% increase in SOD from nadir (smallest SOD recorded) with absolute increase of ≥5 mm → OR appearance of one or more new lesions → OR unequivocal progression of non-target lesions.
6. How do you handle new lesions in RECIST 1.1 assessment?
Answer: → Confirm new lesion is truly new and not missed at baseline → Measure and document clearly → Any unequivocal new lesion = Progressive Disease (PD) regardless of target lesion response.
7. Explain Partial Response (PR) criteria in RECIST 1.1 with steps.
Answer: → ≥30% decrease in SOD from baseline → No new lesions → Non-target lesions must show no unequivocal progression → Confirm with subsequent scan if required by protocol.
8. What is the correct way to manage bone lesions in RECIST 1.1?
Answer: → Pure lytic or mixed bone lesions with soft tissue component ≥10 mm can be target lesions → Blastic lesions are usually non-measurable → Document clearly and use consistent imaging modality.
9. How do you assess response when target lesions become too small to measure in follow-up?
Answer: → Assign a default value of 5 mm → Continue calculating SOD using this value → Do not remove from target list unless completely disappeared.
10. What are the most common RECIST 1.1 mistakes CDM professionals make during data cleaning?
Answer: → Incorrect lymph node axis measurement (long vs short) → Wrong baseline/nadir selection for % change calculation → Misclassifying new lesions or non-measurable disease → Inconsistent documentation across visits.