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Type:
Educational Exhibit
Keywords:
Multidisciplinary cancer care, Metastases, Cancer, Computer Applications-Detection, diagnosis, Comparative studies, PET-CT, Image manipulation / Reconstruction, CT, Oncology, Computer applications
Authors:
M. Kekelidze1, P. Lodise2, M. Tozakidou1, M. Seitel3, G. M. Bongartz1; 1Basel/CH, 2Rome/IT, 3Heidelberg/DE
DOI:
10.1594/ecr2014/C-1689
Background
Over the past three decades there has been a divergence of imaging-based tumor-specific response criteria with the purpose to achieve objective assessment of treatment response in oncologic clinical trials.
In 2009 a revised RECIST 1.1 (Response Evaluation Criteria in Solid Tumors) was developed to address the pitfalls and limitations of previously applied response systems such as WHO and the initial version of RECIST [1].
The major changes included the number of lesions to be assessed,
which has been reduced from a maximum of 10 to a maximum of 5 in total (and from 5 to 2 per organ,
at maximum).
To be considered measurable,
target lesions (TL) must be at least 10 mm in the longest diameter.
Assessment of pathological lymph nodes (LN) was incorporated with a short axis of ≥15mm and considered assessable as target lesions.
Disease progression was clarified in several aspects: In addition to the previous definition of progression in target disease of 20% increase in sum,
a 5 mm absolute increase was added to guard against over calling PD (progressive disease) when the total sum is very small.
Finally,
interpretation of new FDG-PET CT scan in the detection of new lesions was included.
An accurate application of RECIST 1.1 provides a standardized post-treatment monitoring with clearly defined outcome.
However,
when applied incorrectly,
a false radiological interpretation may occur,
resulting in negative implication for patient care.
At our institution we use an automated support software - mint lesion® (Mint Medical,
Heidelberg,
Germany) for the assessment of treatment response.
Lesions are measured by application of a circular measurement tool providing the most precise identification of the longest diameter in target lesions and the longest diameter in short axis of lymph nodes.
All measured diameters are added in the final sum and the treatment outcome calculated.
In this exhibit we demonstrate a spectrum of main pitfalls related to RECIST 1.1 interpretation and provide practical tips how to avoid them in clinical practice.