Should Signet Ring Cell Histology Alter the Treatment Approach for Clinical Stage I Gastric Cancer?

Background: Surgery alone is standard-of-care for stage I gastric adenocarcinoma; however, clinicians can offer preoperative therapy for clinical stage I disease with signet ring cell histology, given its presumed aggressive biology. We aimed to assess the validity of this practice.
Methods: The National Cancer Database (2004-2015) was reviewed for patients with clinical stage I signet ring cell gastric adenocarcinoma who underwent treatment with surgery alone, perioperative chemotherapy, neoadjuvant therapy, or adjuvant therapy. Analysis was stratified by preoperative clinical/pathologic stage. Primary outcome was overall survival (OS).
Results: Of 1018 patients, median age was 60 years (±14); 53% received surgery alone (n = 542), 5% received perioperative chemotherapy (n = 47), 12% received neoadjuvant therapy (n = 125), and 30% received adjuvant therapy (n = 304). For clinical stage I disease, surgery alone was associated with an improved 5-year OS rate (71%) versus perioperative chemotherapy (58%), neoadjuvant therapy (38%), or adjuvant therapy (52%) [overall p < 0.01]. For pathologic stage I, surgery alone had equivalent or improved survival compared with perioperative, neoadjuvant, and adjuvant therapy (5-year OS: 78% vs. 89% [p = 0.77] vs. 64% [p = 0.04] vs. 84% [p = 0.99]). Adjuvant therapy was associated with improved 5-year OS compared with pretreatment for those patients upstaged (37%) to pathologic stage II/III (55% vs. 36% and 34% vs. 7%; all p < 0.01).
Conclusions: This stage-specific study demonstrates improved survival with surgery alone for clinical stage I signet ring cell gastric adenocarcinoma. Despite 37% of clinical stage I patients being upstaged to pathologic stage II/III, adjuvant therapy offers a favorable rescue strategy, with improved outcomes compared with those treated preoperatively. Surgery alone also affords similar or improved survival for pathologic stage I disease versus multimodality therapy. This study challenges the bias to overtreat stage I signet ring cell gastric adenocarcinoma.