Published online Sep 21, 2019. doi: 10.3748/wjg.v25.i35.5334
Peer-review started: May 8, 2019
First decision: July 22, 2019
Revised: August 8, 2019
Accepted: August 19, 2019
Article in press: August 19, 2019
Published online: September 21, 2019
Processing time: 136 Days and 3.8 Hours
Although pathological response is a common endpoint used to assess the efficacy of neoadjuvant chemotherapy (NAC) for gastric cancer, the problem of a low rate of concordance from evaluations among pathologists remains unresolved. Moreover, there is no globally accepted consensus regarding the optimal evaluation.
Pathological response is commonly used for a surrogate marker for progression-free survival and overall survival (OS) after surgery. However, no globally accepted consensus has been reached regarding the optimal cut-off, and the reproducibility between pathologists was limited.
To examine the clinical utility of 10% cut-off for pathological response evaluated using virtual microscopic slides as a prognostic marker.
We retrospectively evaluated pathological specimens of gastric cancer patients who underwent NAC followed by surgery and achieved R0 resection between March 2009 and May 2015. Residual tumor area and primary tumor beds were measured in one captured image slide. We classified patients with < 10% residual tumor relative to the primary tumorous area as responders, and the rest as non-responders; we then compared OS and relapse-free survival (RFS) between these two groups.
Fifty-four patients were evaluated. The concordance rate between two evaluators was 96.2%. Median RFS of 25 responders and 29 non-responders was not reached (NR) vs 18.2 mo [hazard ratio (HR) = 0.35, P = 0.023], and median OS was NR vs 40.7 mo (HR = 0.3, P = 0.016), respectively. This result was also observed even in subgroup analyses for different macroscopic types (Borrmann type 4/non-type 4) and histological types (differentiated/undifferentiated).
The measurement of pathological response using digitally captured virtual microscopic slides may be useful in clinical practice because of its objectivity and its high concordance rate. We consider that this approach is more applicable for evaluating pathological response.
Out results indicated that the measurement of pathological response using digitally captured virtual microscopic slides might be as useful as conventional criteria. However, further studies is needed to evaluate the utility of the method especially for patients who have undergone R1 or R2 resection, and type 4 tumor.