Esophageal adenocarcinoma with any component of signet ring cells portends poor prognosis and response to neoadjuvant therapy

Background: Multiple investigations have shown inferior outcomes for esophageal cancer patients with signet ring cell (SRC) histology. Traditionally, SRC adenocarcinoma has been defined by >= 50% of the tumor composed of SRC. We hypothesized that patients with SRC even<50% would show resistance to standard multimodality therapy with poorer long-term outcomes. Methods: Patients treated with trimodality therapy for adenocarcinoma from 2006 to 2018 were evaluated for SRC on pretreatment biopsy specimens. Available hematoxylin and eosin slides containing SRC tumors were re-reviewed by an esophageal pathologist to quantify the percent composition of SRC. Results: SRC histology was identified on at least 1 pathologic specimen in 106 of 819 (13%) patients. Rates of pathologic complete response (pCR) among usual-type and SRC tumors were 25% (177/713) and 10% (11/106), respectively (P =.006). The pretreatment SRC components did not independently affect the rate of pCR (1%-10% SRC: 4% [2/46] pCR; 11%-49% SRC: 25% [7/28] pCR; 50%-100% SRC: 7% [2/30] pCR). Kaplan-Meier analysis demonstrated worse survival among patients with any degree of SRC present on pretreatment biopsy, as compared with usual-type esophageal adenocarcinoma (P<.0001). Cox multivariable analysis failed to identify a relationship between increasing SRC component and poorer survival. Conclusions: We present the only known evaluation of the percentage of SRC component in esophageal carcinoma. Our data support the hypothesis that esophageal adenocarcinoma with any component of SRC are more resistant to chemoradiation with poorer survival. Pathologic reporting of esophageal adenocarcinoma should include any component of SRC. Alternative therapies in patients with any SRC component may be indicated.