Citations

283 Background: The randomized phase II CALGB 80803 trial evaluated use of PET imaging for early assessment of induction chemotherapy (iCT) responsiveness to tailor therapy for patients with esophageal and gastroesophageal junction adenocarcinomas (EC) undergoing trimodality therapy. The primary endpoint of improving pathologic complete response rates using PET-adapted therapy was met. A companion QOL study aimed to characterize patients’ experience through iCT, chemoradiation (CRT) and surgery (S). Methods: Between 11/2011 and 5/2015, 241 eligible patients were randomized to an iCT regimen: modified oxaliplatin, leucovorin, and 5-fluorouracil (FOLFOX) or carboplatin/paclitaxel (CP), followed by PET scan then CRT, either continuing on the same CT for PET-responders (PET-R) or crossing over to the alternative CT for PET-nonresponders (PET-NR). We prospectively collected QOL domains and symptoms at baseline (T1), after iCT (T2), after CRT (T3), and 3- (T4) and 6- months (T5) after S using the EORTC QLQ-C30, The Esophageal Cancer subscale (EORTC OES18), FACT Neurotoxicity Scale (FACT-NTX), and 6 questions from the PRO-CTCAE. QOL scores were compared between iCT groups and between PET-R and PET-NR at each time point using mixed models. The association of QOL scores at enrollment with overall survival (OS) was tested using Cox regression. Results: 189 patients enrolled on the QOL sub-study, 92 received induction FOLFOX and 97 induction CP. Of those, 110 were PET-R and 79 were PET-NR. 97.9% went on to CRT, and 83.6% underwent S. Global QOL and symptoms statistically significantly worsened from T1 to T2 in 14 of 25 domains, and remained significantly worsened from T1 at: T3 for 19 of 25 domains, T4 for 17 of 25 domains, and T5 for 6 of 25 domains. Changes from T1 significantly favored iFOLFOX (vs iCP) for ability to eat (at T3 and T4), GI symptoms (at T3 and T4), and talking (at T5). Changes from T1 significantly favored iCP (vs iFOLFOX) for neuropathy (at T2, T3, and T4) and coughing (at T5). Proportion of patients reporting worsened PRO-CTCAE scores did not differ between PET-R or PET-NR groups . Multiple QOL domains and symptoms were associated with OS including role functioning, global health status/QOL, appetite loss, pain, dysphagia, and ability to eat (all p<0.002). Conclusions: QOL was impacted most by CRT but returned to baseline 6 months after surgery for most domains. Observed symptom differences did not consistently favor one iCT regimen. Early interventions such as nutritional support and prehabilitation should be studied to improve QOL and OS. Clinical trial information: NCT01333033 .

26 Background: Local therapies have the potential to cure a portion of patients with colorectal cancer with liver-only metastatic disease (CRLM). Peri-operative chemotherapy has not been shown to improve overall survival when added to local therapy in CRLM. Circulating-tumor DNA (ct-DNA) may have potential to help guide management decisions following local therapy. Methods: We conducted a retrospective analysis of health records of CRLM patients who had tumor-informed ct-DNA (Signatera) measurement following curative-intent local therapy prior to August 30th, 2023. Disease-free survival (DFS) was defined as the time from ct-DNA test until radiographic evidence of disease. Descriptive characteristics of the cohort, ct-DNA results and their impact on adjuvant therapy decisions were recorded. Survival analysis was carried out using R software v4.3.1 with survival and survminer packages. The Kaplan–Meier method was used to estimate the survival distribution. Log-rank test was used for comparison. A multivariable Cox proportional hazards model was used to assess prognostic factors associated with DFS ( coxph). Results: 27 patients with CRLM underwent local therapy followed by ct-DNA collection. The median age was 61 years, 67% were male, and 85% were White. Molecular characteristics: KRAS 31%, NRAS/BRAF 0%, microsatellite instability 4%. The median time from initial diagnosis to treatment of liver disease was 21.0 months. 63% of patients received less than 6 months of systemic therapy prior to local therapy. ct-DNA was checked prior to definitive therapy in 12 cases and was positive in 5 cases (detection rate of 42%). Liver-directed therapy involved: resection (n=15), ablation (6), radiation (2) or a combination (4). The median follow-up time from liver-directed therapy was 13.2 months. Post-local therapy chemotherapy was initiated prior to recurrence in 59% of cases. ct-DNA results contributed to immediate post-management decisions in 15% of cases. There were 14 radiographic recurrences (11 to liver only, 3 to other sites). Positive ct-DNA on initial testing following local therapy was associated with poorer DFS in univariate analysis and was the only prognostic factor identified on multivariable analysis. Conclusions: ct-DNA positivity following local therapy for CRLM is associated with earlier recurrence. Baseline testing before local therapy may be important for interpretation of testing results post-local therapy, given frequent missed disease detection. Additional clinical trial data is needed to explore ct-DNA-guided treatment decisions in CRLM. [Table: see text]

22 Background: Glycosylation plays a pivotal role in host immune response during cancer development. Recently, we have reported specific changes in blood-based glycoforms for the early detection of advanced adenomas (AAs) and colorectal cancer (CRC). This study aims to identify glycoproteomic biomarkers associated with various polyp types, as glycosylation abnormalities are linked to neoplastic transformation, and CRC risk varies by polyp histology. Methods: Samples from an observational study (NCT05445570) were used to identify three distinct histologic polyp groups: adenomatous (AP), hyperplastic (HP), or serrated (SP). Combining liquid-chromatography/mass-spectrometry and artificial-intelligence powered data processing, our glycoproteomic profiling platform assessed glycopeptide (GP) and non-glycosylated peptide quantification transitions from the serum samples. We used multi-nominal response logit models to examine the relationship between polyp types and biomarkers. An a priori biomarker panel was interjected as exposures in the model. Each marker is assessed independently for inclusion into our final model. The final model utilized biomarkers found to have a significant association with the presence of AP, SP, or HPs along with age, sex, and BMI. Results: We identified 1,035 subjects with distinct polyp histologies and 1,300 polyp-free controls. We found a significant increase in relative risk (RR) for polyp presence in patients who were: >60 years (AP RR 1.40), male (AP RR 1.74), or had a BMI> 25. From the GP biomarker panel, 15 GPs were associated with risk of polyp presence; however, only 7 GP markers were significantly associated after adjusting for age, sex, and BMI. Two biomarkers were found to have a protective effect for the risk of an adenomatous polyp (RR 0.37; RR 0.39). Three biomarkers increased the risk of an adenomatous polyp (RR 1.31; RR 1.42; RR 1.98). One biomarker was found to increase the risk of a hyperplastic polyp (RR 1.42). Two biomarkers were found to increase the risk of serrated polyps (RR 1.67; RR 2.08) and one biomarker was found to decrease the risk of serrated polyps (RR 0.77). Conclusions: This is a novel exploratory study using GP biomarkers as it relates to risk of polyp presence by distinct histology. The use of these biomarkers allows us to harness the power of glycobiology in the liquid biopsy domain for AAs/CRC detection. The exact function of these GP markers during the development of different polyp types needs to be further explored through future studies.

200 Background: We developed and validated a quantitative segmentation algorithm (QuantCRC) to predict disease recurrence in stage I-III colorectal cancer patients (pts) based on the analysis of digitized hematoxylin and eosin (H+E) stained pathology slides. In this study, we aim to determine if QuantCRC analysis on pre-treated RC biopsies can predict pathological complete response (pCR) after NAT which include total neoadjuvant therapy (TNT), chemoradiation (CRT) and others. Methods: Stage II-IV RC pts treated with curative intent modalities between 2005-2023 at Mayo Clinic and University of Pittsburgh were evaluated. Eligible pts had pre and post-treatment tissue available for analysis. Clinical characteristics, treatment, and outcome data were extracted from the medical record. QuantCRC extracted 15 features: %tumor, %stroma, tumor:stroma ratio, %TB/PDC, %mucin, %necrosis, %high-grade, %signet ring cells, tumor-infiltrating lymphocytes (TILs) per cm2 of a tumor, %immature stroma (tumor bed), %inflammatory stroma (tumor bed), %mature stroma (tumor bed), %immature (stromal region), %inflammatory (stromal region), and %mature (stromal region). The associations between the QuantCRC features and pCR were evaluated using Wilcoxon rank-sum tests and logistic regression models while adjusting for primary tumor location and NAT. Results: The identified 288 pts had the following demographics: median age 60, 59% male, 52% distal tumor, 42% TNT. Pts who achieved pCR had smaller pre-treatment tumors (p=0.03), higher TILS, and lower %immature (stroma) (Table 1). After multivariable adjustment, higher TILS and lower %immature (stroma) remain to be significantly associated with a higher likelihood of pCR. A higher %mature (stroma) and %mature stroma (tumor bed) were also identified, in multivariable models, to be associated with a higher rate of pCR. NAT protocol and tumor location (proximal vs. distal) were not associated with pCR. Conclusions: The ability to integrate pathological features with AI may allow for personalized treatment. Using this technology, we recognize that patients who harbor a more mature stromal archetype and inflammatory tumor predisposition, are more likely to achieve pCR to conventional NAT. These pathological features are not currently incorporated into risk stratification in RC. Additional validation and integration into current risk stratification methods is warranted. [Table: see text]

175 Background: Alterations to mismatch repair (MMR) genes such as MLH1, MSH2, MSH6, and PMS2, can lead to microsatellite instability-high (MSI-H) tumors. MMR mutations can be inherited in Lynch syndrome (LS) but can also be a result of de novo alterations resulting in MSI-H malignancies. Treatment with immune checkpoint inhibitors (ICIs) have been shown to improve survival in such patients (pts) compared to systemic chemotherapy. However, there is a paucity of information in the literature with respect to outcomes of pts with germline vs somatic MMR mutations in MSI-H colorectal cancer (CRC). Furthermore, the presence of underlying BRAF mutation confers resistance to chemotherapy in pts with CRC, however data regarding outcomes with immunotherapy in such pts with MSI-H CRC is lacking. Methods: Pt records from the Mayo Clinic (AZ, MN, FL) between 2008-2023 denoted as MSI-H CRC, were included for retrospective review. Pt demographics, treatment courses, and genomic profiles were collected. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan-Meier method. Outcome differences between sub-groups were accessed with the log rank test and univariate analyses were assessed with Cox-regression. Results: A total of 81 pt records were identified (n = 18 LS, n = 63 non-LS). Stage IV disease was found in 28% of LS pts vs 59% of non-LS pts at diagnosis. Pembrolizumab was the most common ICI selected for metastatic CRC pts for both LS and non-LS pts (65% vs 94%) with median treatment duration for each group 11.7 vs 8.8 months. There were no differences in OS or PFS for any stage between LS vs non-LS. Median OS for all patients was 82 months. For all stage IV patients, median OS was 44 months, and median PFS was 19 months. Interestingly, for stage IV pts treated with immunotherapy, tumors that harbored BRAF V600E mutation (n = 21) vs BRAF wild type (n = 20) had a significantly lower median OS 19 vs 113 months (HR = 2.69, p = 0.043) as well as median PFS 12 vs 95 months (HR = 2.48, p = 0.041). Conclusions: In this study, we found that patient treated with ICIs have similar outcomes in the presence of germline vs. somatic MMR mutations in MSI-H CRC. The presence of an associated BRAF V600E mutation, which occurs in non-LS MSI-H CRC conferred worse outcomes.

17 Background: Age-appropriate colon cancer screening has long demonstrated effectiveness in reducing colon cancer incidence and mortality. However, despite a gradual rise in compliance with colon cancer screening, significant disparities remain, particularly among patients with limited English proficiency (LEP). Multitarget stool DNA (MT-sDNA) testing (Exact Sciences, Madison, WI) has been available over the past decade in the United States as a lower-cost and non-invasive option for screening. In 2019, Exact Sciences began to offer patient navigation services comprising outbound phone, text, and e-mail reminders, and inbound phone support (>200 languages) with all MT-sDNA orders. In this study, we aimed to evaluate the disparity in successful MT-sDNA testing between LEP and EP patients in a time frame when patient navigation services were active. Methods: We performed a retrospective cohort study of patients 45-75 years old enrolled in the primary care setting of our institution who received an order for MT-sDNA screening during a period in which patient navigation services began to be offered. A multi-state Cox model was constructed with time to MT-sDNA or other CRC screening predicted by English proficiency accounting for age and gender. Wald tests were used to test the association of CRC screening completion and English proficiency. Rates of completion of MT-sDNA screening and other CRC screening following MT-sDNA test ordering were calculated using the Kaplan-Meier method. Results: Of the 5016 patients evaluated and referred for multitarget stool DNA testing from May 1st, 2021, and May 1st, 2022, 154 patients were of LEP, and 4862 were English proficient (EP). At 180 days following a MT-sDNA test order the rate of completion for the LEP patients was 50.2% (95% CI: 42.8-58.7%) versus 70.3% (95% 69.1-71.6%) for EP individuals (p=0.001). A small portion of individuals also completed another type of CRC screen, 3.3% for LEP and 2.5% for EP (p=0.99). Conclusions: This study is consistent with the existing research demonstrating LEP as a significant demographic group linked with decreased participation in cancer screening. Our findings indicated that despite the availability of patient navigation services, individuals with LEP were still less likely to complete an MT-sDNA test successfully when compared to those with EP. [Table: see text]

163 Background: Testing for BRAF and KRAS/NRAS mutations, HER2 amplifications, and MSI/MMR status is a standard of care for all patients with mCRC. There are limited real-world (RW) data regarding biomarker testing patterns among robust patients who are candidates for multiple LOT. We evaluated biomarker testing patterns among patients treated in community oncology practices who initiated regorafenib (REGO) and/or trifluridine/tipiracil (FTD/TPI), predominantly in 3rd or later lines of therapy. Methods: A retrospective analysis utilizing electronic medical record data from The US Oncology Network examined adult patients with mCRC who initiated REGO and/or FTD/TPI between 09/01/2015 and 11/30/2022 with follow-up until 05/31/2023. The proportion of patients tested for various biomarkers was assessed. Results: A total of 2684 mCRC patients initiated REGO and/or FTD/TPI (including 895 pts receiving both) in any LOT during the study period. The mean age of patients at baseline was 62.9 years, of whom 54.9% were male, 1599 (59.6%) patients were White and 436 (16.2%) were underrepresented minorities (Black or Hispanic/Latino). Patients were most commonly tested for KRAS mutations (75.2%) and least commonly for HER2 amplifications (22.6%). Age, gender, and race/ethnicity characteristics were similar between treatment subgroups, with 29.6% of minority and 23.1% of white patients not undergoing KRAS testing. Types of biomarkers tested and proportion of patients tested are reported in the table below. Conclusions: About one quarter of patients who were sufficiently robust to receive aggressive therapy did not undergo testing for KRAS, the oldest standard of care biomarker in CRC. We observed disparities by race/ethnicity. We also observed a correlation between rates of testing and treatment intensity, with patients who received both REGO and FTD/TPI having a higher rate of testing than those who received only one of the treatments. Understanding the pitfalls in biomarker testing will help pave the way for appropriate and equitable access to cancer care. [Table: see text]

162 Background: There is a need to improve current risk stratification of stage II and III colorectal cancer (CRC) to better inform risk of recurrence and guide adjuvant chemotherapy. The purpose of this study is to examine whether integration of QuantCRC, an AI-based digital pathology biomarker utilizing hematoxylin and eosin-stained slides, provides improved risk stratification over current American Society of Clinical Oncology (ASCO) guidelines. Methods: ASCO and QuantCRC-integrated risk schemes were applied to an observational cohort of 1,068 stage II and III CRCs. The stage II integrated scheme utilizes pT3 vs. pT4 and QuantCRC-derived risk groups. The stage III integrated scheme utilizes pT1-3 vs. pT4, pN1 vs. pN2, and QuantCRC-derived risk groups. Performance metrics included log-rank test, hazard ratios and Somers’ Dxy rank correlation. Results: Integration of QuantCRC provides improved risk stratification compared to the ASCO scheme for stage II and III CRC. The QuantCRC-integrated scheme placed more stage II tumors in the low-risk group compared to the ASCO scheme (69.3% vs. 60.4%) without decreased 3-year RFS. The QuantCRC-integrated scheme provided larger hazard ratios (HR) for both intermediate-risk (3.04, 95%CI 1.81-5.10, P=2.8x10-5) and high-risk (4.62, 95%CI 2.02-10.61, P=0.0003) groups compared to ASCO intermediate-risk (2.09, 95%CI 1.21-3.63, P=0.008) and high-risk (3.08, 95%CI 1.57-6.01, P=0.001) groups. The QuantCRC-integrated scheme for stage III tumors identified a small group of 80/518 (15.4%) CRCs at very high risk of recurrence with HR of 4.08 (95%CI 2.68-6.23, P=6.5x10-11) compared to a HR of 2.42 (95%CI 1.72-3.38, P=3.1x10-7) for 228/518 (44.0%) high-risk CRCs in the ASCO scheme. QuantCRC-integrated risk groups remained prognostic in stage III CRCs when stratified by presence or absence of any adjuvant chemotherapy. No difference in RFS were seen in QuantCRC-integrated low-risk and intermediate-risk stage III CRCs stratified by 3 vs. 6-months of oxaliplatin-based adjuvant chemotherapy suggesting that these two groups can be treated with 3-months of adjuvant therapy. Conclusions: Incorporation of QuantCRC into risk stratification provides a powerful predictor of RFS that has potential to guide subsequent treatment and surveillance.

115 Background: Randomized clinical trials provide the best evidence for the effects of a new treatment. However, the use of a placebo control arm may present practical and ethical concerns for enrolled patients and treating providers. The CRC ARCAD global database includes a total of 1,673 individual patient data (IPD) treated with placebo plus best supportive care in a salvage-line setting for refractory mCRC. By using placebo IPD, we have proposed to construct a synthetic control arm for clinical trials (Yoshino T. et al., Nature Medicine 2023). Methods: From 40,889 IPD from 59 studies in ARCAD mCRC database, 723 placebo pts were selected from 4 placebo-controlled randomized studies in a salvage-line setting (CORRECT, RECOURSE, CONCUR and TERRA). We analyzed the impact of baseline patient characteristics and various prognostic factors on outcome in the placebo control. Results: The adjusted hazard ratios (HRs) (95% confidence interval [CI]) were 0.52 (0.40-0.67) for the number of metastatic sites (1 vs 2+), 0.71 (0.59-0.84) for ECOG performance status (PS) (0 vs 1), 0.54 (0.45-0.66) for liver metastases (No vs Yes), 0.54 (0.40-0.71) for peritoneal metastases (No vs Yes), and 0.51 (0.38-0.70) for Royal Marsden Hospital (RMH) Score (consisting of albumin level, number of metastatic sites, and LDH level) (0-1 vs 2-3). Conclusions: Number of metastatic sites, ECOG PS, liver metastasis, peritoneal metastasis and RMH Score were significant prognostic factors in patients with mCRC receiving placebo in a salvage-line setting. Further prognostic factors should be investigated to increase the accuracy of the proposed synthetic control arm. [Table: see text]

107 Background: The "No Placebo Initiative" demonstrated that the survivals of patients (pts) receiving placebo in a salvage-line setting, exhibited no significant difference across trials (CORRECT, RECOURSE, CONCUR and TERRA). Therefore, we believe that a nomogram can be generated using the ARCAD database to predict survival of pts who completed standard therapy. Methods: Of 40,889 Individual patient data (IPD) from 59 studies, 723 pts received placebo from 4 randomized studies were pooled. The potential prognostic factors considered include BMI and Age. Imputed datasets were constructed by a multiple imputation method since the original dataset contains some missing values. Overall survival (OS) was defined as the time from randomization to death from any cause. Multivariate Cox proportional hazards models for OS were estimated based on the variables showing clinically and statistically significant by univariate analysis. Prediction performance of the final model was evaluated using the concordance index for survival data and calibration plots. Results: From univariate and multivariate analysis, ECOG performance status, Royal Marsden Hospital score (calculated by albumin level, LDH level, and number of metastatic site), primary site location, liver meta, peritoneal meta were selected as variables. We successfully developed a highly accurate nomogram to predict post-standard treatment prognosis for pts with mCRC. Concordance index for OS was 0.66. Conclusions: Although further validation in other cohorts is needed, this nomogram could be very useful to estimate the survival for clinical practice and enrolling in clinical trials. [Table: see text]