RECIST 1.1 Calculator

Response Evaluation Criteria In Solid Tumors

1 Target Lesions (max 5)

Enter measurements in mm. Non-nodal: longest diameter. Lymph nodes: short axis.

2 Additional Criteria

About RECIST 1.1

Response Evaluation Criteria In Solid Tumors (RECIST) version 1.1 is the standard method for evaluating tumor response to treatment. Published in 2009, it provides reproducible criteria for classifying response in clinical trials and practice.

Response Categories

Response Criteria
CR (Complete Response) Disappearance of all target lesions. All lymph nodes <10mm short axis.
PR (Partial Response) ≥30% decrease in sum of diameters from baseline
SD (Stable Disease) Neither sufficient decrease for PR nor increase for PD
PD (Progressive Disease) ≥20% increase from nadir AND ≥5mm absolute increase. Or new lesion.

Target Lesion Selection

  • Maximum 5 lesions total, 2 per organ
  • Select largest, most reproducibly measurable lesions
  • Non-nodal: ≥10mm longest diameter (CT slice ≤5mm)
  • Lymph nodes: ≥15mm short axis (pathological)

Measurement Rules

  • Non-nodal lesions: Measure longest diameter
  • Lymph nodes: Measure short axis (even when used as target)
  • Too small to measure: Use 5mm default
  • Disappeared: Record as 0mm
  • Lesions merge: Measure combined longest axis
  • Lesions split: Sum individual measurements

The 5mm Rule

To prevent false PD from measurement variability, progression requires both:

  • ≥20% increase from nadir
  • ≥5mm absolute increase

If only percentage threshold met but absolute change <5mm, classify as SD.

Baseline vs Nadir

  • Baseline: Pre-treatment measurement (for PR calculation)
  • Nadir: Lowest sum during treatment (for PD calculation)
  • Nadir may equal baseline if no decrease occurred

References

  1. Eisenhauer EA, Therasse P, Bogaerts J, et al. New response evaluation criteria in solid tumours: revised RECIST guideline (version 1.1). Eur J Cancer. 2009;45(2):228-247. doi:10.1016/j.ejca.2008.10.026
  2. Schwartz LH, Litière S, de Vries E, et al. RECIST 1.1 - Update and clarification: From the RECIST committee. Eur J Cancer. 2016;62:132-137. doi:10.1016/j.ejca.2016.03.081
  3. Nishino M, Jackman DM, Hatabu H, et al. New Response Evaluation Criteria in Solid Tumors (RECIST) Guidelines for Advanced Non-Small Cell Lung Cancer. J Thorac Oncol. 2010;5(12):2044-2048. doi:10.1097/JTO.0b013e3181f60709