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Target tumors are measured in the longest diameter except when the location is a lymph node, then they are measured in the longest perpendicular. The examples in this disease response supplement use TRTESTCD = "LDIAM" (Longest Diameter) for measurements of non-lymph node target tumors and TRTESTCD = "LPERP" (Longest Perpendicular) for measurements of lymph node target tumors. The SDTMIG examples have previously used TRTESTCD = "DIAMETER" (Diameter) for measurements of both lymph nodes and non-lymph nodes. Either representation is acceptable for RECIST 1.1. The latter approach requires looking at the anatomical location in conjunction with the TRTESTCD to know whether the diameter was measured in the longest diameter or the longest perpendicular. The "LDIAM" and "LPERP" tests provide more specificity in the TRTESTCD itself and does not required looking to the anatomical location. In addition, "LDIAM" and "LPERP" are tests used in other disease response criteria so the use of these two tests provides standardization that work across criteria for the same measurement. Some sponsors prefer the approach used within this disease response supplement due to these reasons.
Target tumors may split may split (fragment) and/or merge (coalesce) during a study. See example 4.2 for a detailed example on the recording preferred representation of the measurements of split and merged tumors. Regardless of the representation of split and merged lesions, it is essential that the summation of the diameters is accurate.
In RECIST1.1, the following calculations are used in determination of the target response: sum of the diameters of target tumors (target sum), percentage change from baseline in the target sum, and percentage change from nadir in the target sum (smallest target sum at any assessment). These are referred to as summary values in the examples below. These summary values are not typically collected/calculated in investigator CRFs but they are usually provided by independent assessors. When derived in EDC, Summary values not in the collected data may be derived in the analysis datasets (i.e., ADaM).
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