Smyrk, Thomas C.

Tumor cell proliferation rate determined by either Ki-67 index or mitotic count (MC) has shown to be a prognostic factor for gastrointestinal neuroendocrine tumors in general, and after its incorporation in the 2010 World Health Organization tumor grading system, it has become essentially mandatory in pathology reports for all gastrointestinal neuroendocrine tumors, regardless of tumor location. Nevertheless, clinical significance for the Ki-67 index or MC has not been well demonstrated in small intestinal neuroendocrine tumor (SINET), especially those without distant metastasis, the majority of which have very low proliferation rates. We assessed the clinical behavior of 130 SINETs in relation to stage, Ki-67 index, MC, and other pathologic features. Most SINETs (86%) were grade 1 and 14% were grade 2. There were no grade 3 tumors or poorly differentiated neuroendocrine carcinomas. On multivariate analysis, age, Ki-67 index >5%, MC >10/50 high-power field, stage IV, and liver metastases were associated with increased risk of death in all patients. When both stage and grade were considered, Ki-67 index >5% was associated with a nearly 4-fold increased risk of death in stage IV cases (n=60). In contrast, Ki-67 index did not show prognostic value for patients with stages I to III disease (n=70), although MC >1/50 high-power field was significantly associated with death on multivariable analysis. Our study confirms that liver metastasis and increased tumor cell proliferation rate are independent prognostic factors for SINETs, but shows that most SINETs have a very low proliferation rate, which limits its value for predicting tumor behavior. By combining staging and grading information, we demonstrate different roles and cutoff values of Ki-67 index and MC in SINET with different stages.

Abstract Background: The increased number of T-lymphocytes residing in the tumors of colorectal cancer (CRC) patients is consistently shown to predict better survival of CRC patients independent of stage. In addition to tumor itself, T-lymphocytes also infiltrate normal tissues adjacent to tumors; however, little is known about how the inter-individual T-cell variability in tumor-adjacent tissues affects CRC prognosis. Our goal was to characterize total T-cells in colorectal tumor and tumor-adjacent tissues and study their associations with all-cause and CRC-specific survival in the Iowa Women’s Health Study. Methods: We constructed tissue microarrays and quantified CD3 antibody staining (Clone F.7.238; Dako), an established marker for total T-cells, in paraffin-embedded tissue samples from 463 women diagnosed with incident CRC from 1986-2002 (mean age at diagnosis was 74 years). Up to 3 tumor and 3 tumor-adjacent cores were immunostained for each person. An experienced pathologist quantified CD3+ T cells in each area using 4 categories: non-detected, mild (1-10 cells per 0.28 mm2); moderate (11-29 cells per 0.28 mm2); and strong infiltration (≥30 cells per 0.28 mm2). The obtained scores were averaged over all quantified cores for each person. Cox regression was used to estimate the hazard ratio (HR) and 95% CI for all-cause and CRC mortality in relation to (1) tumor score; (2) tumor-adjacent score; and (3) the ratio of tumor to tumor-adjacent score, hereafter called Score ratio. All scores were categorized in quartiles. The final model adjusted for age at diagnosis, SEER stage, tumor grade, body mass and smoking history. Results: During follow-up for a maximum of 25 years, 67% of participants diagnosed with CRC died (~30% died from CRC). There was a weak but significant correlation between CD3 tumor and tumor-adjacent scores (Spearman coefficient: r=0.15, p=0.02). CD3 tumor score was inversely associated with stage and was higher in those with proximal colon cancer, and for MSI-high, CIMP-high and BRAF-mutated tumors. The HRs (95%CI) for the highest versus lowest category of CD3 tumor score were 0.61 (0.44-0.84) (p-trend=0.003) for all-cause mortality and 0.27 (0.15-0.48) (p-trend <0.0001) for CRC-specific mortality. The tumor-adjacent score was not associated with any characteristics or death. The associations between the Score ratio and all-cause and CRC survival mirrored those for the tumor score but were weaker. The HRs (95%CI) for the highest versus lowest quartile of the Score ratio were 0.70 (0.45-1.09) (p-trend=0.09) for all-cause and 0.45 (0.23-0.87) (p-trend=0.003) for CRC-specific mortality. Conclusions. Based on data from prospectively identified CRC cases in the IWHS cohort, colorectal tumor T-cell infiltration is associated with improved survival. Further investigation is needed to determine the T-cell subtypes that are most predictive of CRC survival outcomes. Citation Format: Anna E. Prizment, Robert A. Vierkant, Thomas C. Smyrk, Lori S. Tillmans, Heather H. Nelson, Charles F. Lynch, Stephen N. Thibodeau, Timothy R. Church, James R. Cerhan, Kristin E. Anderson, Paul J. Limburg. Associations between total T-lymphocytes and colorectal cancer survival in a prospective cohort study of older women [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2247. doi:10.1158/1538-7445.AM2017-2247

BACKGROUNDOxaliplatin in combination with either 5‐fluorouracil or capecitabine is commonly used as first‐line therapy for patients with small bowel adenocarcinoma. The addition of irinotecan improves survival in other gastrointestinal tumors but at the cost of hematologic toxicity. The authors performed a phase 2 cooperative group study (North Central Cancer Treatment Group N0543, Alliance) using genotype‐dosed capecitabine, irinotecan, and oxaliplatin (gCAPIRINOX), with dosing assigned based on UDP glucuronosyltransferase family 1 member A1 (UGT1A1) genotype to test: 1) whether the addition of irinotecan would improve outcomes; and 2) whether UGT1A1 genotype‐based dosing could optimize tolerability.METHODSPreviously untreated patients with advanced small bowel adenocarcinoma received irinotecan (day 1), oxaliplatin (day 1), and capecitabine (days 2‐15) in a 21‐day cycle and were dosed with gCAPIRINOX according to UGT1A1*28 genotypes (6/6, 6/7, and 7/7).RESULTSA total of 33 patients (17 with the 6/6 genotype, 10 with the 6/7 genotype, and 6 with the 7/7 genotype) were enrolled from October 2007 to November 2013; 73% were male, with a mean age of 64 years (range, 41‐77 years). Location of the primary tumor included the duodenum (58%), jejunum (30%), and ileum (9%). The regimen yielded a confirmed response rate of 37.5% (95% confidence interval, 21%‐56%), with a median progression‐free survival of 8.9 months and a median overall survival of 13.4 months. Neither hematologic toxicity (grade ≥3 in 52.9%, 30.0%, and 33.3%, respectively, of the 6/6, 6/7, and 7/7 genotype groups) nor tumor response rate (41.2%, 33%, and 33%, respectively) were found to differ significantly by UGT1A1 genotype.CONCLUSIONSUGT1A1 genotype‐directed dosing (gCAPIRINOX) appears to be feasible with favorable rates of hematologic toxicity compared with prior 3‐drug studies in unselected patients. Larger studies would be needed to determine the regimen's comparability to oxaliplatin and capecitabine (CapeOx) alone or if response/toxicity differs among patients with different UGT1A1 genotypes. Cancer 2017;123:3494‐501. © 2017 American Cancer Society.

288 Background: Programmed-death 1 (PD-1) receptor and its corresponding ligand, PD-L1, have been found to be clinically relevant in maintaining immune tolerance to malignant cells in an increasing number of tumor types. We have previously shown that nearly half of 48 randomly selected, resected small bowel adenocarcinomas at any stage exhibit positive PD-L1 expression. Furthermore, a larger quantity of tumor infiltrating lymphocytes (TILs) within the tumor stroma or microsatellite instability (MSI-H) have been associated with improved likelihood of response to PD-1 and PD-L1 inhibitors. We have descriptively characterized the stromal components of small bowel adenocarcinomas to determine if similar tumor/stromal features to drug-responsive tumors can be seen. Methods: 30 tumors were immunohistochemically stained for CD8 (T-lymphocytes), CD68 (macrophages), and e-cadherin. They were morphologically screened for MSI-H status with light microscopy. PD-L1 staining was previously performed and reported. Results: Of the 30 tumors, there was no correlation between the density of macrophages and T-lymphocytes, nor was there a correlation with the burden of immune cells with e-cadherin expression. 14/30 (47%) tumors had 3+/4+ expression of CD8+ lymphocytes. 7/14 (50%) of these tumors were morphologically MSI-H. No tumors with low CD8+ cells (1+/2+) were MSI-H. PD-L1 expression colocalized exclusively with macrophages and not with lymphocytes. Conclusions: There appears to be no association between the proportions of immune cells and basement membrane integrity. MSI-H tumors are more likely to have a greater quantity of CD8+ lymphocytes in the stroma; however, PD-L1 stromal expression appears to colocalize with macrophages. Further pathologic characterization is needed in patients treated with PD-1 and other immune checkpoint inhibitors to determine the clinical significance of these observations.

460 Background: The immune response has emerged as a strong prognostic factor in colon cancer. Whereas CD8+ T cells mediate antitumor response, regulatory T cells expressing FoxP3+ can antagonize this effect, though prognostic data conflict. These markers have yet to be analyzed with MMR status, which is important since dMMR tumors show enhanced immune response. Methods: CD8+ and FoxP3+ density were analyzed by immunohistochemistry (IHC) in resected stage II and III colon carcinomas (N = 216) from participants in phase III adjuvant 5-fluorouracil-based trials. High vs low immune density was dichotomized at the median. MMR status, determined by IHC or analysis of microsatellite instability, was categorized as dMMR (12%) or proficient MMR (pMMR). Cox models, stratified by study, were adjusted for age, stage, grade and, where noted, MMR. Results: The association of FoxP3+ density with overall survival (OS) differed by CD8+ density (P for interaction = .040). By multivariable analysis, FoxP3+high was significantly associated with improved OS in CD8+low tumors (hazard ratio 0.43 [95% confidence interval 0.19 – 0.95]; P = .030], but not in CD8+high tumors (P = .91). Results were consistent after MMR adjustment. We then determined their prognostic impact in the larger pMMR subset (N = 119). Tumors with high FoxP3+ were associated with improved OS in cases with low, but not high, CD8+ density ( Table ). These patients (FoxP3+high, CD8+low) had similar 5-year OS rates as 107 dMMR cases from parent studies (89% vs 80%; P = .74), despite having distinct clinicopathologic features. Conclusions: The prognostic impact of FoxP3+ T cells depends on CD8+, indicating the importance of analyzing both in combination. High FoxP3+ exerts a paradoxically favorable survival impact, but only when CD8+ is low. Survival in pMMR tumors with high FoxP3+ and low CD8+ was similar to that of dMMR tumors, indicating that a favorable pMMR subset can be identified. [Table: see text]

Abstract Background: Host immune response may predict the course of colorectal cancer. We examined the survival of 468 colorectal cancer patients associated with two tumor-infiltrating immune biomarkers, the number of cytotoxic T lymphocytes (CTLs), and the activated CTLs, as reflected by the number of cells expressing granzyme B (GZMB) in the prospective Iowa Women's Health Study. Methods: Using paraffin-embedded tissue samples, we constructed and immunostained tumor microarrays with CD8 (for CTL) and GZMB antibodies. We scored CTL and GZMB densities in tumor epithelial and stromal tissues and also created a composite score for each biomarker (sum of the scores across tissue compartments). Cox regression estimated the HR and 95% confidence intervals (CI) for all-cause and colorectal cancer–specific death associated with each composite score. Results: CTL and GZMB composite scores were positively correlated (r = 0.65) and each biomarker was inversely correlated with stage at diagnosis. Both composite scores were higher in proximal colon tumors and tumors characterized by MSI-high, CIMP-high, or BRAF mutation status. HRs (95% CI) were 0.53 (0.38–0.75; Ptrend = 0.0004) and 0.66 (0.51–0.86; Ptrend = 0.002) for all-cause death, respectively, and 0.30 (0.18–0.51; Ptrend < 0.0001) and 0.41 (0.27–0.63; Ptrend < 0.0001) for colorectal cancer–related death, respectively. Including CTL and GZMB scores simultaneously in the model significantly improved the predictive performance of the models for all-cause and colorectal cancer–related death. Conclusions: Higher tumor infiltration with CTL and GZMB cells is associated with improved all-cause and cancer-specific survival of colorectal cancer patients. Impact: Both the number of CTLs and GZMB appear to be useful prognostic factors in colorectal cancer, irrespective of stage. Cancer Epidemiol Biomarkers Prev; 26(4); 622–31. ©2016 AACR.