Background

The generation of long-term durable tumor immunity and prolonged disease-free survival depends on the ability to generate and support CD8+ central memory T-cells. Microsatellite-stable colon cancer is resistant to currently available immunotherapies; thus, development of novel mechanisms to increase both lymphocyte infiltration and central memory formation are needed to improve outcomes in these patients. We have previously demonstrated that both interleukin-2 (IL-2) and LIGHT (TNFSF14) independently enhance antitumor immune responses and hypothesize that combination immunotherapy may increase the CD8+ central memory T-cell response.

Methods

Murine colorectal cancer tumors were established in syngeneic mice. Tumors were treated with control, soluble, or liposomal IL-2 at established intervals. A subset of animal tumors overexpressed tumor necrosis superfamily factor LIGHT (TNFSF14). Peripheral blood, splenic, and tumor-infiltrating lymphocytes were isolated for phenotypic studies and flow cytometry.

Results

Tumors exposed to a combination of LIGHT and IL-2 experienced a decrease in tumor size compared with IL-2 alone that was not demonstrated in wild-type tumors or between other treatment groups. Combination exposure also increased splenic central memory CD8+ cells compared with IL-2 administration alone, while not increasing tumor-infiltrating lymphocytes. In the periphery, the combination enhanced levels of circulating CD8 T-cells and central memory T-cells, while also increasing circulating T-regulatory cells.

Conclusions

Combination of IL-2, whether soluble or liposomal, with exposure to LIGHT results in increased CD8+ central memory cells in the spleen and periphery. New combination immunotherapy strategies that support both effector and memory T-cell functions are critical to enhancing durable antitumor responses and warrant further investigation.

Background

Neoadjuvant chemotherapy (NAC) is standard management for localized gastric cancer (GC). Attrition during NAC due to treatment-related toxicity or functional decline is considered a surrogate for worse biologic outcomes; however, data supporting this paradigm are lacking. We investigated factors predicting attrition and its association with overall survival (OS) in GC.

Methods

Patients with nonmetastatic GC initiating NAC were identified from the US Safety-Net Collaborative (2012-2014). Patient/treatment-related characteristics were compared between attrition/nonattrition cohorts. Cox models determined factors associated with OS.

Results

Of 116 patients initiating NAC, attrition during prescribed NAC occurred in 24%. No differences were observed in performance status, comorbidities, treatment at safety-net hospital, or clinicopathologic factors between cohorts. Despite absence of distinguishing factors, attrition was associated with worse OS (median: 11 vs. 37 months; p = 0.01) and was an independent predictor of mortality (hazard ratio [HR]: 4.7, 95% confidence interval [CI]: 1.5-15.2; p = 0.02). Fewer patients with attrition underwent curative-intent surgery (39% vs. 89%; p < 0.001). Even in patients undergoing surgical exploration (n = 89), NAC attrition remained an independent predictor of worse OS (HR: 50.8, 95% CI: 3.6-717.8; p = 0.004) despite similar receipt of adjuvant chemotherapy.

Conclusion

Attrition during NAC for nonmetastatic GC is independently associated with worse OS, even in patients undergoing surgery. Attrition during NAC may reflect unfavorable tumor biology not captured by conventional staging metrics.

Background and objectives

Perioperative therapy is a favored treatment strategy for gastric cancer. We sought to assess utilization of this approach at safety net hospitals (SNH) and tertiary referral centers (TRC).

Materials and methods

Patients in the US Safety Net Collaborative (2012-2014) with resectable gastric cancer across five SNH and their sister TRC were included. Primary outcomes were receipt of neoadjuvant chemotherapy (NAC) and perioperative therapy.

Results

Of 284 patients, 36% and 64% received care at SNH and TRC. The distribution of Stage II/III resectable disease was similar across facilities. Receipt of NAC at SNH and TRC was similar (56% vs. 46%, p = 0.27). Compared with overall clinical stage, 38% and 36% were pathologically downstaged at SNH and TRC, respectively. Among patients who received NAC, those who also received adjuvant chemotherapy at SNH and TRC were similar (66% vs. 60%, p = 0.50). Asian race and higher clinical stage were associated with receipt of perioperative therapy (both p < 0.05) while treatment facility type was not.

Conclusions

There was no difference in utilization of a perioperative treatment strategy between facility types for patients with gastric cancer. Pathologic downstaging from NAC was similar across treatment facilities, suggesting similar quality and duration of therapy. Treatment at an SNH is not a barrier to receiving standard-of-care perioperative therapy for gastric cancer.

Background

Diagnostic laparoscopy (DL) is a key component of staging for locally advanced gastric adenocarcinoma (GA). We hypothesized that utilization of DL varied between safety net (SNH) and affiliated tertiary referral centers (TRCs).

Methods

Patients diagnosed with primary GA eligible for DL were identified from the US Safety Net Collaborative database (2012-2014). Clinicopathologic factors were analyzed for association with use of DL and findings on DL. Overall survival (OS) was analyzed by Kaplan-Meier method.

Results

Among 233 eligible patients, 69 (30%) received DL, of which 24 (35%) were positive for metastatic disease. Forty percent of eligible SNH patients underwent DL compared to 21.5% at TRCs. Lack of insurance was significantly associated with decreased use of DL (OR 0.48, p < 0.01), while African American (OR 6.87, p = 0.02) and Asian race (OR 3.12, p ≤ 0.01), signet ring cells on biopsy (OR 3.14, p < 0.01), and distal tumors (OR 1.62, p < 0.01) were associated with increased use. Median OS of patients with a negative DL was better than those without DL or a positive DL (not reached vs. 32 vs. 12 months, p < 0.005, Figure 1).

Conclusions

Results from DL are a strong predictor of OS in GA; however, the procedure is underutilized. Patients from racial minority groups were more likely to undergo DL, which likely accounts for higher DL rates among SNH patients.

Background

Hispanic patients have a higher incidence of gastric cancer when compared to non-Hispanics. Outlining clinicodemographic characteristics and assessing the impact of ethnicity on stage-specific survival may identify opportunities to improve gastric cancer care for this population.

Methods

Patients with gastric cancer in the US Safety Net Collaborative (2012-2014) were retrospectively reviewed. Demographics, clinicopathologic characteristics, operative details, and outcomes were compared between Hispanic and non-Hispanic patients. Early onset gastric cancer was defined as age <50 years. Kaplan-Meier and Cox proportional-hazards models were used to identify the impact of ethnicity on disease-specific survival (DSS).

Results

Seven hundred and ninety-seven patients were included, of which 219 (28%) were Hispanic. Hispanic patients were more likely to seek care at safety-net hospitals (66 vs 39%) and be uninsured (36 vs 17%), and less likely to have a primary care provider (PCP) (46 vs 75%; all P<0.05). Hispanic patients were twice as likely to present with early onset gastric cancer (28 vs 15%) and were more frequently diagnosed in the emergency room (54 vs 37%) with both abdominal pain and weight loss (44 vs 31%; all P <0.05). Treatment paradigms, operative outcomes, and DSS were similar between Hispanic and non-Hispanic patients when accounting for cancer stage. Cancer stage, pathologically positive nodes, and negative surgical margins were independently associated with DSS.

Conclusions

A diagnosis of gastric cancer must be considered in previously healthy Hispanic patients who present to the emergency room with both abdominal pain and weight loss. Fewer than 50% of Hispanic patients have a PCP, indicating poor outpatient support. Efforts to improve outpatient support and screening may improve gastric cancer outcomes in this vulnerable population.