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Background: The value of baseline fluorodeoxyglucose-positron emission tomography-computed tomography (PET-CT) remains uncertain once gastroesophageal cancer is metastatic. We hypothesized that assessment of detailed PET-CT parameters (maximum standardized uptake value [SUVmax] and/or total lesion glycolysis [TLG]), and the extent of metastatic burden could aid prediction of probability of response or prognosticate. Methods: We retrospectively analyzed treatment-naive patients with stage 4 gastroesophageal cancer (December 2002–August 2017) who had initial PET-CT for cancer staging at MD Anderson Cancer Center. SUVmax and TLG were compared with treatment outcomes for the full cohort and subgroups based on metastatic burden (≤2 or >2 metastatic sites). Results: We identified 129 patients with metastatic gastroesophageal cancer who underwent PET-CT before first-line therapy. The median follow-up time was 61 months. The median overall survival (OS) was 18.5 months; the first progression-free survival (PFS) was 5.5 months. SUVmax or TLG of the primary tumor or of all metastases combined had no influence on OS or PFS, whether the number of metastases was ≤2 or >2. Overall response rates (ORRs) to first-line therapy were 48% and 45% for patients with ≤2 and >2 metastases, respectively (nonsignificant). ORR did not differ based on low or high values of SUVmax or TLG. Conclusions: This is the first assessment of a unique set of PET-CT data and its association with outcomes in metastatic gastroesophageal cancer. In our large cohort of patients, detailed analyses of PET-CT (by SUVmax and/or TLG) did not discriminate any parameters examined. Thus, baseline PET-CT in untreated metastatic gastroesophageal cancer patients has limited or no utility.

Background: Patients with localized gastric adenocarcinoma (LGAC), who get pre-operative therapy, have heterogeneous/unpredictable outcomes. Predictive clinical variables/biomarkers are not established. Methods: We analyzed 107 LGAC patients who had chemoradiation and surgery. LGACs were grouped for (1) presence/absence of signet ring cell histology (SRC) and (2) histologic grade: G2 or G3. %SRC was assessed (0, 1-10, 11-49, and 50-100%) and correlated with pathologic complete response (pathCR) or Results: Most patients were men (60%), had stage cIII LGAC (50%), and received chemotherapy before chemoradiation (93%). Most had G3 tumors (78%) and SRC (58%). Presence of SRC was associated with a lower rate of pathCR (11 vs. 36%, p = 0.004), and the association remained significant even with a low percentage of SRC (1-10%; p = 0.014). The higher the fraction of SRC, the lower was the probability of pathCR (p = 0.03). G3 and SRC led to a shorter overall survival (OS) (p = 0.046 and p = 0.038, respectively). yp stage independently prognosticated OS and recurrence-free survival (p < 0.001). Conclusion: Our novel findings suggest that LGACs with SRC are relatively chemoradiation resistant compared to LGACs without SRC. A higher fraction of SRC is associated with higher resistance. Upon validation/biomarker(s) evaluation, reporting of the fraction of SRC may be warranted.

Background: In patients with localized gastric adenocarcinoma (LGAC) who receive preoperative therapy, tools to predict response or prognosticate outcome before therapy are lacking. We used initial standardized uptake value (iSUV) of positron emission tomography (PET) to evaluate its association with overall survival (OS). Methods: We identified 60 patients with confirmed LGAC who were treated with preoperative chemoradiation and had a baseline PET in addition to other routine staging. Fisher's exact test and Wilcoxon's rank sum test were used to determine the association between iSUV and other variables, and the log-rank test and Cox proportional hazards model were used for survival analysis. Results: The median iSUV was 6 (range, 0-28). The presence of signet ring cells in pretreatment biopsies correlated highly with low iSUV (≤6; p = 0.0017). Patients with a high iSUV (>6) had a longer OS compared to those with a low iSUV (≤6; p = 0.0344). iSUV was not an independent predictor (p = 0.12); however, the risk of death was reduced for patients with an iSUV >6 (hazard ratio = 0.26). Conclusion: Our novel findings show that among LGAC patients treated with preoperative chemoradiation and surgery, those with a high iSUV have longer OS than patients with a low iSUV. iSUV appears to have a predictive role in patients with LGAC when treated with preoperative chemoradiation.

Background: Nearly 50% of gastric cancer patients are diagnosed with advanced gastric cancer (AGC). Therapy is palliative but results in ill effects. The median overall survival (OS) of AGC patients is often Methods: A retrospective analysis of AGC patients in our database was carried out. The patients were divided into two groups: asymptomatic or symptomatic. We sought to assess whether the delay of systemic therapy was harmful in asymptomatic patients. Results: A total of 135 patients were analyzed. Most patients were symptomatic (68%), males (67%), and had low ECOG scores (0-1; 85%). In univariate analyses, ECOG performance status 0 (p = 0.005), delayed initiation of therapy (p = 0.03), and lack of symptoms (p = 0.03) were associated with a longer OS. The multivariate model for OS identified only ECOG performance status as an independent prognosticator of longer OS (p = 0.02). Asymptomatic patients who had delayed (≥4 weeks) systemic therapy had an OS rate of 77% at 1 year compared to 58% for patients treated within 4 weeks (p = 0.47). Conclusion: Symptomatic AGC patients had a poor outcome compared to asymptomatic AGC patients. Treatment delay in asymptomatic patients had no detrimental effect on OS, suggesting that the timing of therapy can be based on patient selection.