Anal Carcinoma, Version 2.2023, NCCN Clinical Practice Guidelines in Oncology

This discussion summarizes the NCCN Clinical Practice Guidelines for managing squamous cell anal carcinoma, which represents the most common histologic form of the disease. A multidisciplinary approach including physicians from gastroenterology, medical oncology, surgical oncology, radiation oncology, and radiology is necessary. Primary treatment of perianal cancer and anal canal cancer are similar and include chemoradiation in most cases. Follow-up clinical evaluations are recommended for all patients with anal carcinoma because additional curative-intent treatment is possible. Biopsy-proven evidence of locally recurrent or persistent disease after primary treatment may require surgical treatment. Systemic therapy is generally recommended for extrapelvic metastatic disease. Recent updates to the NCCN Guidelines for Anal Carcinoma include staging classification updates based on the 9th edition of the AJCC Staging System and updates to the systemic therapy recommendations based on new data that better define optimal treatment of patients with metastatic anal carcinoma.

Folic Acid Supplementation Promotes Hypomethylation in Both the Inflamed Colonic Mucosa and Colitis-Associated Dysplasia

PURPOSE

The purpose of this study was to assess the effect of folic acid (FA) supplementation on colitis-associated colorectal cancer (CRC) using the azoxymethane/dextran sulfate sodium (AOM/DSS) model.

METHODS

Mice were fed a chow containing 2 mg/kg FA at baseline and randomized after the first DSS treatment to receive 0, 2, or 8 mg/kg FA chow for 16 weeks. Colon tissue was collected for histopathological evaluation, genome-wide methylation analyses (Digital Restriction Enzyme Assay of Methylation), and gene expression profiling (RNA-Seq).

RESULTS

A dose-dependent increase in the multiplicity of colonic dysplasias was observed, with the multiplicity of total and polypoid dysplasias higher (64% and 225%, respectively) in the 8 mg FA vs. the 0 mg FA group (p < 0.001). Polypoid dysplasias were hypomethylated, as compared to the non-neoplastic colonic mucosa (p < 0.05), irrespective of FA treatment. The colonic mucosa of the 8 mg FA group was markedly hypomethylated as compared to the 0 mg FA group. Differential methylation of genes involved in Wnt/β-catenin and MAPK signaling resulted in corresponding alterations in gene expression within the colonic mucosa.

CONCLUSIONS

High-dose FA created an altered epigenetic field effect within the non-neoplastic colonic mucosa. The observed decrease in site-specific DNA methylation altered oncogenic pathways and promoted colitis-associated CRC.

Dysregulation of miR-1-3p: An Early Event in Colitis-Associated Dysplasia

Detection of colorectal dysplasia during surveillance colonoscopy remains the best method of determining risk for colitis-associated colorectal cancer (CAC). miRNAs (miRs) show great promise as tissue-specific biomarkers of neoplasia. The goal of this study was to explore the miR expression profile of precancerous dysplastic lesions in the AOM/DSS mouse model and identify early molecular changes associated with CAC. Epithelial cells were laser-microdissected from the colonic mucosa (inflamed versus dysplastic) of mice with AOM/DSS-induced colitis. A miR signature that can distinguish inflamed non-neoplastic mucosa from dysplasia was identified. Bioinformatic analyses led to the discovery of associated miR gene targets and enriched pathways and supported the construction of a network interaction map. miR-1a-3p was one of the miRs with the highest number of predicted targets, including Cdk6. Interestingly, miR-1a-3p and Cdk6 were down- and up-regulated in dysplastic lesions, respectively. Transfection of HCT116 and RKO cells with miR-1a-3p mimics induced apoptosis and cell cycle arrest in G1, suggesting its biological function. A slight reduction in the level of CDK6 transcripts was also observed in cells transfected with miR-1. These data provide novel insight into the early molecular alterations that accompany the development of CAC and identify a miR signature that represents a promising biomarker for the early detection of colitis-associated dysplasia.

Rectal Cancer, Version 2.2022, NCCN Clinical Practice Guidelines in Oncology

This selection from the NCCN Guidelines for Rectal Cancer focuses on management of malignant polyps and resectable nonmetastatic rectal cancer because important updates have been made to these guidelines. These recent updates include redrawing the algorithms for stage II and III disease to reflect new data supporting the increasingly prominent role of total neoadjuvant therapy, expanded recommendations for short-course radiation therapy techniques, and new recommendations for a “watch-and-wait” nonoperative management technique for patients with cancer that shows a complete response to neoadjuvant therapy. The complete version of the NCCN Guidelines for Rectal Cancer, available online at NCCN.org, covers additional topics including risk assessment, pathology and staging, management of metastatic disease, posttreatment surveillance, treatment of recurrent disease, and survivorship.

Abstract 1553: miR-1 targets Cdk6 and controls cell cycle progression and apoptosis in colitis-associated dysplasia

Detection of colorectal dysplasia during surveillance colonoscopy is currently the best method of determining risk of colitis-associated colorectal cancer (CAC). An understanding of the early molecular changes associated with the development of these lesions will inform the identification of new biomarkers for earlier detection. miRNAs (miRs), highly conserved noncoding RNAs, show great promise as stable, tissue-specific biomarkers of neoplasia. We previously identified 12 miRs that are differentially-expressed in colitis-associated dysplasias (flat and polypoid) vs. inflamed colonic mucosa from mice treated with AOM/DSS. miR-1, a putative tumor suppressor, was downregulated in colitis-associated dysplasias. Analysis of the mRNA expression profile of AOM/DSS-induced dysplasias and prediction of the interactions between the miRs and their targets led to the selection of the Cdk6 as the target of miR-1 to be further investigated, based on its: 1) upregulation in AOM/DSS-induced dysplasia; and 2) association with cell cycle progression and inflammatory signaling. The goal of the present study was to validate the predicted interaction between miR-1 and Cdk6 and assess the biological function of miR-1 in vitro. The ability of miR-1 to interact with the 3’UTR of Cdk6 mRNA was assessed using a dual luciferase assay. Co-transfection of HCT116 or RKO colon carcinoma cells with Cdk6-WT and miR-1 mimics led to a significant reduction in relative luciferase activity in both cell lines (30%, p=0.0117 and 47%, p=0.0269; respectively). Transfection with the Cdk6-Mut did not alter relative luciferase activity, confirming the Cdk6 binding site was specific for miR-1. The biological function of miR-1 was assessed in HCT116 and RKO cells reverse-transfected with miR-1 and cel-miR-67 (negative control) for 48 hrs. Apoptosis (AnnexinV+ cells) and cell cycle progression (% of cells in G0/G1, G2/M and S phase) were evaluated by flow cytometry, and proliferation by cell count (Trypan Blue). HCT116 and RKO transfected with the miR-1 mimic exhibited a higher proportion of apoptotic cells than the negative control (30% and 20% increase, p=0.0022 and 0.0013, respectively). Cell cycle analyses revealed the miR-1 mimic induced cell cycle arrest (G0/G1) in both cell lines (p&lt;0.05). In HCT116 cells, this was accompanied by a reduction in the percentage of cells in G2/M (p=0.002) and S (p&lt;0.001) phase. No effect of miR-1 on total cell number was observed. These results demonstrate that Cdk6 is a direct target of miR-1, and suggest that downregulation of this miR in dysplastic lesions contributes to CAC by inducing cell cycle progression and inhibiting apoptosis. These data provide novel insight into the early molecular changes that accompany the development of colitis-associated dysplasia and may serve as biomarkers for early detection of neoplasia. Supported by the Timothy P. and Aurora M. Hughes Fund for Colon Cancer Research.

Citation Format: Mariana F. Fragoso, Geysson J. Fernandez, Lisa Vanderveer, Harry S. Cooper, Michael Slifker, Margie L. Clapper. miR-1 targets Cdk6 and controls cell cycle progression and apoptosis in colitis-associated dysplasia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1553.

Neoadjuvant Chemoradiation Impacts the Prognostic Effect of Surgical Margin Status in Pancreatic Adenocarcinoma

BACKGROUND

Many studies show significantly improved survival after R0 resection compared with R1 resection in pancreatic adenocarcinoma (PAC); however, the effect of neoadjuvant chemoradiation (NACRT) on this association is unknown.

OBJECTIVE

The aim of this study was to evaluate the prognostic significance of positive surgical margins (SMs) after NACRT compared with upfront surgery + adjuvant therapy in PAC.

METHODS

All cases of surgically resected PAC at a single institution were reviewed from 1996 to 2014; patients treated with palliative intent, metastatic disease, and biliary/ampullary tumors were excluded. The primary endpoint was overall survival (OS).

RESULTS

Overall, 300 patients were included; 134 patients received NACRT with concurrent 5-fluorouracil or gemcitabine followed by surgery, and 166 patients received upfront surgery (+ adjuvant chemotherapy in 72% of patients and RT in 65%); 31% of both groups had a positive SM (+SM). The median OS for patients with a +SM or negative SM (-SM) was 26.6 and 31.6 months, respectively for NACRT, and 12.0 and 24.5 months, respectively, for upfront surgery. OS was significantly improved with -SM compared with +SM in both groups (p = 0.006). When resection yielded +SM, NACRT patients had improved OS compared with upfront surgery patients (p < 0.001). On multivariable analysis, +SM in the upfront surgery group (hazard ratio [HR] 2.94, 95% confidence interval [CI] 2.04-4.24; p < 0.001) and older age (HR 1.01, 95% CI 1.00-1.03, per year; p = 0.007) predicted worse OS. +SM in the NACRT group was not associated with worse OS (HR 1.09, 95% CI 0.72-1.65; p = 0.70).

CONCLUSION

Patients with a positive margin after NACRT and surgery had longer survival compared with patients with a positive margin after upfront surgery. NACRT should be strongly considered for patients at high risk of R1 resections.

Suppression of Colon Tumorigenesis in Mutant Apc Mice by a Novel PDE10 Inhibitor that Reduces Oncogenic β-Catenin

Previous studies have reported that phosphodiesterase 10A (PDE10) is overexpressed in colon epithelium during early stages of colon tumorigenesis and essential for colon cancer cell growth. Here we describe a novel non-COX inhibitory derivative of the anti-inflammatory drug, sulindac, with selective PDE10 inhibitory activity, ADT 061. ADT 061 potently inhibited the growth of colon cancer cells expressing high levels of PDE10, but not normal colonocytes that do not express PDE10. The concentration range by which ADT 061 inhibited colon cancer cell growth was identical to concentrations that inhibit recombinant PDE10. ADT 061 inhibited PDE10 by a competitive mechanism and did not affect the activity of other PDE isozymes at concentrations that inhibit colon cancer cell growth. Treatment of colon cancer cells with ADT 061 activated cGMP/PKG signaling, induced phosphorylation of oncogenic β-catenin, inhibited Wnt-induced nuclear translocation of β-catenin, and suppressed TCF/LEF transcription at concentrations that inhibit cancer cell growth. Oral administration of ADT 061 resulted in high concentrations in the colon mucosa and significantly suppressed the formation of colon adenomas in the Apc^+/min-FCCC mouse model of colorectal cancer without discernable toxicity. These results support the development of ADT 061 for the treatment or prevention of adenomas in individuals at risk of developing colorectal cancer. PREVENTION RELEVANCE: PDE10 is overexpressed in colon tumors whereby inhibition activates cGMP/PKG signaling and suppresses Wnt/β-catenin transcription to selectively induce apoptosis of colon cancer cells. ADT 061 is a novel PDE10 inhibitor that shows promising cancer chemopreventive activity and tolerance in a mouse model of colon cancer.

Clinical Application of Chromosome Microarray Analysis in the Diagnosis of Lipomatous Tumors

Well-differentiated liposarcoma/atypical lipomatous tumor (WDLS/ALT) and dedifferentiated liposarcoma (DDLS) have characteristic supernumerary ring and giant marker chromosomes involving the chromosomal region 12q13-15 which contains MDM2 (12q15), CDK4 (12q14.1), HMGA2 (12q14.3), YEATS4 (12q15), CPM (12q15), and FRS2 (12q15). Detecting MDM2 amplification by fluorescence in situ hybridization (FISH) is considered to be the gold standard for the diagnosis of WDLS/ALT and DDLS. In this study, formalin fixed paraffin embedded clinical specimens (16 liposarcomas and 19 benign lipomatous tumors) were used to detect MDM2 amplification and other chromosomal alterations in WDLS/ALT and DDLS by single nucleotide polymorphism-based chromosome microarray (CMA). All 16 liposarcomas showed MDM2 amplification with a MDM2/cep12 ratio from 2.4 to 8.4 by CMA. Ten (62.5%) of these cases had CDK4/cep12 ratio ≥2.0. All the cases without CDK4 amplification were from the thigh. The MDM2/cep12 ratio of all the benign lipomatous tumors (19/19) was within the normal limits. Twenty-one of the 35 benign lipomatous tumors and liposarcomas were also tested for MDM2 amplification by FISH. All the FISH results were consistent with the CMA results (100%). Along with MDM2 amplification, all 16 liposarcomas (100%) also showed amplification of YEATS4, CPM and FRS2. Only 11 of 16 (69%) cases showed HMGA2 amplification. In conclusion, this study demonstrated that CMA on routine formalin fixed paraffin embedded tissue is a sensitive and specific clinical test for detection of MDM2 gene amplification. Moreover, CMA allows simultaneous detection of genomic changes of interest including CDK4 and others, which provides enriched information for diagnosing lipomatous tumors.

Abstract 2374: Identification of altered miRNA-gene interactions in AOM/DSS induced colitis-associated dysplasia

Although significant progress has been made in delineating the pathways that contribute to ulcerative colitis (UC)-associated tumorigenesis, the early molecular alterations that fuel disease progression remain poorly understood. microRNAs (miRs) have emerged as important modulators of inflammatory pathways and their aberrant expression has been associated with initiation and progression of malignancy. The goal of this study is to identify gene-miR interactions that occur early in experimental UC and contribute to the development of colitis-associated dysplasia. The mRNA and miR expression profile of laser microdissected colon specimens (inflamed mucosa vs. dysplasia) from Swiss Webster mice with AOM/DSS-induced colitis was interrogated using the Mouse Gene Expression Microarrays 4x44K v2 (Agilent®) and miRNA Mouse platform (NanoString®). Data were analyzed using R/Bioconductor and nSolverTM (NanoString®). Differentially expressed miRs (n=12, p&lt;0.001) were validated by RT-qPCR (n=9) and used for target prediction (TargetScan v. 7.2). The differential expression of the predicted target genes (mRNA array) vs. miRs was compared and filtered to include only those with contrasting changes in expression (e.g. downregulated miR and upregulated mRNA). The resulting list of 98 genes was subjected to pathway enrichment analysis using EnrichR. Network interactions were calculated using STRING and visualized on Cytoscape v.3.8.0. Gene ontology analyses revealed 23 terms associated with the pathogenesis and progression of UC, including TNFα signaling via NF-kB, G1 to S cell cycle control, Wnt and Hedgehog signaling. Analyses of miR targets revealed that miR-30c, miR-145a and miR-1a controlled the largest number of predicted target genes (35%, 26% and 18%, respectively). These data suggest an important role of these top miRs (putative tumor suppressors) in UC-associated tumorigenesis, based on their downregulation in dysplasias and corresponding upregulation of their oncogenic targets (Sox9, Ccnd2 and Cdk6). Consistent with our findings, Sox9 contributes to carcinogenesis through its effect on stem cells. The Ccnd2/Cdk6 complex is considered a central component of signaling pathways that regulate cell cycle G1/S transition during neoplastic development. Therefore, early interaction of these miRs with their respective target genes may contribute to the transition of inflamed colonic mucosa to dysplasia in mice with experimental colitis. Additional in vitro validation of the predicted interactions remains in progress. (Supported by a generous donation from Aurora and Timothy Hughes).

Citation Format: Mariana F. Fragoso, Geysson J. Fernandez, Lisa Vanderveer, Harry S. Cooper, Wen-Chi Chang, Michael Slifker, Karthik Devarajan, Yan Zhou, Eric Ross, Margie L. Clapper. Identification of altered miRNA-gene interactions in AOM/DSS induced colitis-associated dysplasia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2374.

SMARCA2-NR4A3 is a novel fusion gene of extraskeletal myxoid chondrosarcoma identified by RNA next-generation sequencing

Extraskeletal myxoid chondrosarcoma (EMC) is a rare sarcoma of uncertain differentiation, characterized by recurrent chromosomal translocation involving NR4A3 (9q22.33) in more than 90% of cases. Five fusion partners for NR4A3 have been described including: EWSR1 (22q12.2), TAF15 (17q12), FUS (16p11.2), TCF12 (15q21), and TFG (3q12.2). This report describes a patient with an EMC at the dorsum of the right foot. The tumor showed a cord-like and reticular pattern in a background of myxoid matrix. The tumor cells demonstrated an epithelioid morphology with prominent nucleoli. The tumor cells were positive for synaptophysin, GFAP, with focal positivity for CD117, S100, Cam5.2, and NSE, and negative for AE1/3, desmin, and SMA. An RNA next-generation sequencing test showed a SMARCA2-NR4A3 gene fusion which has not been previously reported. The exon 3 of SMARCA2 was fused to exon 3 of NR4A3. This fusion was confirmed by NR4A3 break-apart FISH, although both SMARCA2 (9p24.3) and NR4A3 (9q22.33) are located on chromosome 9. The tumor cells showed retained expression of INI1 and SMARCA2 by immunohistochemistry.

Dysplastic Aberrant Crypt Foci: Biomarkers of Early Colorectal Neoplasia and Response to Preventive Intervention

The discovery of aberrant crypt foci (ACF) more than three decades ago not only enhanced our understanding of how colorectal tumors form, but provided new opportunities to detect lesions prior to adenoma development and intervene in the colorectal carcinogenesis process even earlier. Because not all ACF progress to neoplasia, it is important to stratify these lesions based on the presence of dysplasia and establish early detection methods and interventions that specifically target dysplastic ACF (microadenomas). Significant progress has been made in characterizing the morphology and genetics of dysplastic ACF in both preclinical models and humans. Image-based methods have been established and new techniques that utilize bioactivatable probes and capture histologic abnormalities in vivo are emerging for lesion detection. Successful identification of agents that target dysplastic ACF holds great promise for intervening even earlier in the carcinogenesis process to maximize tumor inhibition. Future preclinical and clinical prevention studies should give significant attention to assessing the utility of dysplastic ACF as the earliest identifiable biomarker of colorectal neoplasia and response to therapy.See all articles in this Special Collection Honoring Paul F. Engstrom, MD, Champion of Cancer Prevention.

Colon Cancer, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

This selection from the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Colon Cancer focuses on systemic therapy options for the treatment of metastatic colorectal cancer (mCRC), because important updates have recently been made to this section. These updates include recommendations for first-line use of checkpoint inhibitors for mCRC, that is deficient mismatch repair/microsatellite instability-high, recommendations related to the use of biosimilars, and expanded recommendations for biomarker testing. The systemic therapy recommendations now include targeted therapy options for patients with mCRC that is HER2-amplified, or BRAF V600E mutation-positive. Treatment and management of nonmetastatic or resectable/ablatable metastatic disease are discussed in the complete version of the NCCN Guidelines for Colon Cancer available at NCCN.org. Additional topics covered in the complete version include risk assessment, staging, pathology, posttreatment surveillance, and survivorship.

Novel Protein-Based Vaccine against Self-Antigen Reduces the Formation of Sporadic Colon Adenomas in Mice

Simple Summary

Colorectal cancer remains a leading cause of cancer-related mortality worldwide. However, high-risk populations with a genetic predisposition for colorectal cancer could benefit greatly from novel and efficacious immunopreventive strategies that afford long-lasting protection. The achaete-scute family bHLH transcription factor 2 (Ascl2) has been identified as a promising target for immunoprevention of colorectal cancer, based on its induction during the formation and progression of colorectal tumors and its minimal expression observed in healthy tissue. The goal of the present study was to determine the efficacy of a protein-based vaccine targeting Ascl2 in combination with an anti-PD-1 treatment in a spontaneous colorectal cancer mouse model. This novel vaccine strategy promotes potent tumor-specific immunity, and prevents the formation of colon adenomas in mice. The results demonstrate that Ascl2 is a promising target for immunoprevention for individuals at elevated risk of developing colorectal cancer.

Abstract

Novel immunopreventive strategies are emerging that show great promise for conferring long-term protection to individuals at high risk of developing colorectal cancer. The KISIMA vaccine platform utilizes a chimeric protein comprising: (1) a selected tumor antigen; (2) a cell-penetrating peptide to improve antigen delivery and epitope presentation, and (3) a TLR2/4 agonist to serve as a self-adjuvant. This study examines the ability of a KISIMA vaccine against achaete-scute family bHLH transcription factor 2 (Ascl2), an early colon cancer antigen, to reduce colon tumor formation by stimulating an anti-tumor immune response. Vaccine administrations were well-tolerated and led to circulating antibodies and antigen-specific T cells in a mouse model of colorectal cancer. To assess preventive efficacy, the vaccine was administered to mice either alone or in combination with the immune checkpoint inhibitor anti-PD-1. When delivered to animals prior to colon tumor formation, the combination strategy significantly reduced the development of colon microadenomas and adenomas, as compared to vehicle-treated controls. This response was accompanied by an increase in the intraepithelial density of CD3+ T lymphocytes. Together, these data indicate that the KISIMA-Ascl2 vaccine shows great potential to be a safe and potent immunopreventive intervention for individuals at high risk of developing colorectal cancer.

First-in-Human Phase 1b Trial of Quinacrine Plus Capecitabine in Patients With Refractory Metastatic Colorectal Cancer

BACKGROUND

Quinacrine plus a fluoropyrimidine has in vivo efficacy against metastatic colorectal cancer (mCRC). This phase 1b trial evaluated the combination of quinacrine plus capecitabine in patients with treatment-refractory mCRC.

PATIENTS AND METHODS

Using a modified Simon accelerated titration design, adults with treatment-refractory mCRC were treated with capecitabine 1000 mg/m² twice daily for 14/21-day cycle, and escalating doses of quinacrine 100 mg daily, 100 mg twice daily, and 200 mg twice daily for 21 days. The primary endpoint was identifying the maximum tolerated dose, determining tolerability and safety. In an expansion cohort, it was overall response rate and time to tumor progression (TTP).

RESULTS

Ten patients (median age of 60 years) were treated in phase 1b. The first 2 quinacrine dosing levels were well tolerated. Dose-limiting toxicities were seen in 3 patients treated with quinacrine 200 mg twice daily. Five additional patients tolerated quinacrine 100 mg twice daily without further dose-limiting toxicities, thus establishing the maximum tolerated dose. Seven additional expansion-cohort patients enrolled onto the study before quinacrine manufacturing ceased within the United States. Five patients experienced stable disease, 1 partial response, and 10 disease progression. Median TTP overall was 2.12 months and median overall survival 5.22 months for the 17 patients.

CONCLUSION

Capecitabine and quinacrine can be safely administered at the maximum tolerated dose of capecitabine 1000 mg/m² by mouth twice daily on days 1-14 and quinacrine 100 mg by mouth twice daily on days 1-21 of a 21-day cycle in mCRC patients. Although the expansion study was halted early, TTP was in line with other studies of refractory mCRC, suggesting activity of this regimen in heavily pretreated patients.

Small Bowel Adenocarcinoma, Version 1.2020, NCCN Clinical Practice Guidelines in Oncology

Small bowel adenocarcinoma (SBA) is a rare malignancy of the gastrointestinal tract that has increased in incidence across recent years. Often diagnosed at an advanced stage, outcomes for SBA are worse on average than for other related malignancies, including colorectal cancer. Due to the rarity of this disease, few studies have been done to direct optimal treatment, although recent data have shown that SBA responds to treatment differently than colorectal cancer, necessitating a separate approach to treatment. The NCCN Guidelines for Small Bowel Adenocarcinoma were created to establish an evidence-based standard of care for patients with SBA. These guidelines provide recommendations on the workup of suspected SBA, primary treatment options, adjuvant treatment, surveillance, and systemic therapy for metastatic disease. Additionally, principles of imaging and endoscopy, pathologic review, surgery, radiation therapy, and survivorship are described.

Smooth muscle tumors of the gastrointestinal tract: an analysis of prognostic features in 407 cases

Smooth muscle tumors represent the second most common mural mesenchymal neoplasm in the gastrointestinal tract, but established criteria for prognostic assessment of these tumors are lacking. A large cohort of surgically resected intramural gastrointestinal smooth muscle tumors from 31 institutions was analyzed to identify potential prognostic features. Pathologic features were assessed by expert gastrointestinal and/or soft tissue pathologists at each center. Immunohistochemical confirmation was required. A total of 407 cases from the esophagus (n = 97, 24%), stomach (n = 180, 44%), small bowel (n = 74, 18%), and colorectum (n = 56, 14%) were identified. Patients ranged in age from 19 to 92 years (mean 55 years), with a slight female predominance (57%). Mean tumor size was 5.4 cm, with the largest tumor measuring 29 cm. Disease progression following surgery, defined as local recurrence, metastasis, or disease-related death, occurred in 56 patients (14%). Colorectal tumors were most likely to progress, followed by small bowel and gastric tumors. None of the esophageal tumors in this series progressed. Receiver operator characteristic analysis identified optimal cutoffs of 9.8 cm and 3 mitoses/5 mm² for discriminating between progressive and non-progressive tumors. Histologic features strongly associated with progression by univariate analysis included moderate-to-severe atypia, high cellularity, abnormal differentiation (defined as differentiation not closely resembling that of normal smooth muscle), tumor necrosis, mucosal ulceration, lamina propria involvement, and serosal involvement (P < 0.0001 for all features). Age, sex, and margin status were not significantly associated with progression (P = 0.23, 0.82, and 0.07, respectively). A risk assessment table was created based on tumor site, size, and mitotic count, and Kaplan-Meier plots of progression-free survival for each subgroup revealed progression-based tiers. Based on our findings, it appears that nonesophageal gastrointestinal smooth muscle tumors measuring >10 cm and/or showing ≥3 mitoses/5 mm² may behave aggressively, and therefore close clinical follow-up is recommended in these cases.

NCCN Guidelines Insights: Rectal Cancer, Version 6.2020

The NCCN Guidelines for Rectal Cancer provide recommendations for the diagnosis, evaluation, treatment, and follow-up of patients with rectal cancer. These NCCN Guidelines Insights summarize the panel discussion behind recent important updates to the guidelines. These updates include clarifying the definition of rectum and differentiating the rectum from the sigmoid colon; the total neoadjuvant therapy approach for localized rectal cancer; and biomarker-targeted therapy for metastatic colorectal cancer, with a focus on new treatment options for patients with BRAF V600E- or HER2 amplification-positive disease.

Anal Carcinoma, Version 2.2018, NCCN Clinical Practice Guidelines in Oncology

The NCCN Guidelines for Anal Carcinoma provide recommendations for the management of patients with squamous cell carcinoma of the anal canal or perianal region. Primary treatment of anal cancer usually includes chemoradiation, although certain lesions can be treated with margin-negative local excision alone. Disease surveillance is recommended for all patients with anal carcinoma because additional curative-intent treatment is possible. A multidisciplinary approach including physicians from gastroenterology, medical oncology, surgical oncology, radiation oncology, and radiology is essential for optimal patient care.

Rectal Cancer, Version 2.2018, NCCN Clinical Practice Guidelines in Oncology

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Rectal Cancer address diagnosis, staging, surgical management, perioperative treatment, management of recurrent and metastatic disease, disease surveillance, and survivorship in patients with rectal cancer. This portion of the guidelines focuses on the management of localized disease, which involves careful patient selection for curative-intent treatment options that sequence multimodality therapy usually comprised of chemotherapy, radiation, and surgical resection.

NCCN Guidelines Insights: Colon Cancer, Version 2.2018

The NCCN Guidelines for Colon Cancer provide recommendations regarding diagnosis, pathologic staging, surgical management, perioperative treatment, surveillance, management of recurrent and metastatic disease, and survivorship. These NCCN Guidelines Insights summarize the NCCN Colon Cancer Panel discussions for the 2018 update of the guidelines regarding risk stratification and adjuvant treatment for patients with stage III colon cancer, and treatment of BRAF V600E mutation-positive metastatic colorectal cancer with regimens containing vemurafenib.

Abstract 3864: A novel PDE10/β-catenin pathway inhibitor, MCI-030, for the treatment of colorectal cancer

Over 90% of colorectal cancers harbor mutations in β-catenin or pathway components (e.g. APC) that stabilize β-catenin, causing nuclear translocation and constitutive Tcf-mediated transcription of genes encoding proteins essential for the proliferation and survival of tumor cells. We recently reported that the cyclic nucleotide degrading phosphodiesterase (PDE) isozyme PDE10 is overexpressed in colorectal cancers relative to normal tissue. Its expression and enzymatic activity are essential for colon tumor cell growth, as evidenced by knockdown of PDE10 expression using siRNA or inhibition of enzyme activity using known inhibitors such as PF-2545920. PDE10 inhibition in tumor cells expressing high levels of PDE10 causes increased intracellular cGMP levels to activate PKG and phosphorylate β-catenin, which induces ubiquitination and proteasomal degradation to suppress nuclear translocation and Tcf transcriptional activity. Conversely, ectopic expression of PDE10 in normal colonocytes or precancerous adenoma cells causes increased levels of β-catenin and the expression of proteins (e.g. cyclin D and survivin) essential for the proliferation and survival of tumor cells. To identify novel antitumor PDE10 inhibitors, we screened a chemically diverse library of indenes for PDE10 and tumor cell growth inhibitory activity. Following extensive chemical optimization, MCI-030 emerged as a potent and selective inhibitor of tumor cell growth. Similar to PF-2545920, but with appreciably greater potency and tumor cell selectivity, MCI-030 inhibited colon tumor cell growth by activating cGMP/PKG signaling to phosphorylate and induce β-catenin degradation. MCI-030 also inhibited colon tumor cell spheroid formation and reduced spheroid size and growth at concentrations that inhibit PDE10. Oral administration of MCI-030 significantly inhibited colon tumor formation in the Apc+/min-FCCC mouse model without discernable toxicity. Importantly, unlike PDE10 inhibitors developed to cross the blood-brain barrier for the treatment of CNS disorders, MCI-030 lacks the sedation side effects. Together, these findings support preclinical development of MCI-030 for the treatment of colorectal cancer as a novel PDE10 inhibitor capable of selectively inhibiting the growth of tumors harboring β-catenin or APC mutations. Funding provided by NCI grants R01CA131378, R01CA148817, R01CA197147, and R01CA155638.

Citation Format: Antonio B. Ward, Xi Chen, Jacob Valiyaveettil, Kevin Lee, Wen-Chi L. Chang, Yulia Maxuitenko, Veronica Ramirez-Alcantara, Kristy Berry, Luciana Madeira da Silva, Bing Zhu, Tyler Mattox, Michael R. Boyd, Adam B. Keeton, Margie L. Clapper, Harry S. Cooper, Gary A. Piazza. A novel PDE10/β-catenin pathway inhibitor, MCI-030, for the treatment of colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3864.

Self-antigen MASH2 combined with the AS15 immunostimulant induces tumor protection in colorectal cancer mouse models

Human achaete scute homolog 2 (HASH2) and its murine ortholog MASH2 are potential targets for colorectal cancer immunotherapy. We assessed immunogenicity and antitumor potential of recombinant MASH2 protein combined with AS15 immunostimulant (recMASH2+AS15) in CB6F1 and Apc^+/Min-FCCC mice. CB6F1 mice received 4 injections of recMASH2+AS15 or AS15 alone before challenge with TC1-MASH2 tumor cells (Tumor Challenge). Apc^+/Min-FCCC mice received 9 injections of recMASH2+AS15 or vehicle (phosphate buffer saline [PBS] or AS15 alone), before (two independent Prophylactic Studies) or after (Immunotherapy) colon adenomas were detectable by colonoscopy. CB6F1 mice immunized with recMASH2+AS15 had a significantly smaller mean tumor size and improved survival rate compared to controls (104 mm² vs. 197 mm² [p = 0.009] and 67% vs. 7% [p = 0.001], respectively). In Prophylactic Study 1, the mean number of colon adenomas was significantly lower in Apc^+/Min-FCCC mice receiving recMASH2+AS15 compared to PBS (1.8 [95% confidence interval 1.0–3.3] vs. 5.2 [3.7–7.4], p = 0.003). Fewer microadenomas were observed in recMASH2+AS15 groups compared to PBS in both Prophylactic Studies (Study 1: mean 0.4 [0.2–1.0] vs. 1.5 [0.9–2.4], p = 0.009; Study 2: 0.4 [0.2–0.6] vs. 1.1 [0.8–1.5], p = 0.001). In the Immunotherapy Study, fewer colon adenomas tended to be observed in recMASH2+AS15-treated mice (4.1 [2.9–6.0]) compared to controls (AS15 4.7 [3.3–6.6]; PBS 4.9 [3.5–6.9]; no significant difference). recMASH2+AS15 induced MASH2-specific antibody and CD4+ responses in both mouse models. recMASH2+AS15 partially protected mice against MASH2-expressing tumors and reduced spontaneous colorectal adenomas in Apc^+/Min-FCCC mice, indicating that MASH2/HASH2 antigens are targets for colorectal cancer immunotherapy.

Differential preventive activity of sulindac and atorvastatin in Apc+/Min-FCCCmice with or without colorectal adenomas

OBJECTIVE

The response of subjects to preventive intervention is heterogeneous. The goal of this study was to determine if the efficacy of a chemopreventive agent differs in non-tumour-bearing animals versus those with colorectal tumours. Sulindac and/or atorvastatin was administered to Apc^+/Min-FCCC mice with known tumour-bearing status at treatment initiation.

DESIGN

Male mice (6-8 weeks old) underwent colonoscopy and received control chow or chow with sulindac (300 ppm), atorvastatin (100 ppm) or sulindac/atorvastatin. Tissues were collected from mice treated for 14 weeks (histopathology) or 7 days (gene expression). Cell cycle analyses were performed on SW480 colon carcinoma cells treated with sulindac, atorvastatin or both.

RESULTS

The multiplicity of colorectal adenomas in untreated mice bearing tumours at baseline was 3.6-fold higher than that of mice that were tumour free at baseline (P=0.002). Atorvastatin completely inhibited the formation of microadenomas in mice that were tumour free at baseline (P=0.018) and altered the expression of genes associated with stem/progenitor cells. Treatment of tumour-bearing mice with sulindac/atorvastatin led to a 43% reduction in the multiplicity of colorectal adenomas versus untreated tumour-bearing mice (P=0.049). Sulindac/atorvastatin increased the expression of Hoxb13 and Rprm significantly, suggesting the importance of cell cycle regulation in tumour inhibition. Treatment of SW480 cells with sulindac/atorvastatin led to cell cycle arrest (G0/G1).

CONCLUSIONS

The tumour status of animals at treatment initiation dictates response to therapeutic intervention. Atorvastatin eliminated microadenomas in tumour-free mice. The tumour inhibition observed with Sul/Atorva in tumour-bearing mice was greater than that achieved with each agent.

Abstract 5045: Inflammation is upregulated in the normal colonic epithelium and stroma of Apc+/Min-FCCCmice with colon tumors

The Apc+/Min-FCCC mouse harbors a point mutation in the Apc tumor suppressor gene and is highly susceptible to the development of multiple colon tumors. Despite being maintained for many years as an inbred colony, Apc+/Min-FCCC mice are heterogeneous with respect to the time to colon tumor development and the number of colon tumors that ultimately form. This model therefore serves as a powerful tool with which to better understand the earliest events that lead to tumorigenesis. Identification of early alterations in these animals may provide targets for effective, long-term tumor prevention. The goal of this study was to characterize early changes in gene expression in the nonneoplastic colonic epithelium and stroma that may contribute to tumor formation in Apc +/Min-FCCC mice. Animals were defined as ‘tumor-bearing' if they harbored at least one gross colon tumor at necropsy. No lesions were detected at necropsy in the remaining animals (‘tumor-free'). Normal tissue was collected for analysis from the distal colon at least 1 cm away from the nearest tumor. Histologically-normal epithelial and stromal cells were microdissected from frozen tissue sections. Gene expression profiling was performed using the Agilent Mouse 4x44K microarray chip. Differentially expressed genes were selected using an FDR of 10% and a ≥ 2-fold change in gene expression. Gene set enrichment analyses confirmed the enrichment of stromal genes in samples of isolated stroma (p&lt; 0.05). Numerous genes were differentially expressed in tumor-free vs. tumor-bearing ApcMin/+ mice, in both the epithelial and stromal compartments. Gene Ontology enrichment analyses revealed the associated biological processes that were dysregulated, including inflammation, immune cell migration, and response to bacterium (FDR&lt;0.1%). These findings indicate that inflammatory processes are altered in the nonneoplastic colon well in advance of tumor formation and represent promising targets for preventive intervention.

Citation Format: Alyssa A. Leystra, Lisa Vanderveer, Yan Zhou, Harry S. Cooper, Sergei Grivennikov, Margie L. Clapper. Inflammation is upregulated in the normal colonic epithelium and stroma of Apc+/Min-FCCCmice with colon tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5045.

Colon Cancer, Version 1.2017, NCCN Clinical Practice Guidelines in Oncology

This portion of the NCCN Guidelines for Colon Cancer focuses on the use of systemic therapy in metastatic disease. Considerations for treatment selection among 32 different monotherapies and combination regimens in up to 7 lines of therapy have included treatment history, extent of disease, goals of treatment, the efficacy and toxicity profiles of the regimens, KRAS/NRAS mutational status, and patient comorbidities and preferences. Location of the primary tumor, the BRAF mutation status, and tumor microsatellite stability should also be considered in treatment decisions.

Plecanatide-mediated activation of guanylate cyclase-C suppresses inflammation-induced colorectal carcinogenesis in Apc+/Min-FCCC mice

AIM

To evaluate the effect of orally administered plecanatide on colorectal dysplasia in Apc^+/Min-FCCC mice with dextran sodium sulfate (DSS)-induced inflammation.

METHODS

Inflammation driven colorectal carcinogenesis was induced in Apc^+/Min-FCCC mice by administering DSS in their drinking water. Mice were fed a diet supplemented with plecanatide (0-20 ppm) and its effect on the multiplicity of histopathologically confirmed polypoid, flat and indeterminate dysplasia was evaluated. Plecanatide-mediated activation of guanylate cyclase-C (GC-C) signaling was assessed in colon tissues by measuring cyclic guanosine monophosphate (cGMP) by ELISA, protein kinase G-II and vasodilator stimulated phosphoprotein by immunoblotting. Ki-67, c-myc and cyclin D1 were used as markers of proliferation. Cellular levels and localization of β-catenin in colon tissues were assessed by immunoblotting and immunohistochemistry, respectively. Uroguanylin (UG) and GC-C transcript levels were measured by quantitative reverse transcription polymerase chain reaction (RT-PCR). A mouse cytokine array panel was used to detect cytokines in the supernatant of colon explant cultures.

RESULTS

Oral treatment of Apc^+/MinFCCC mice with plecanatide produced a statistically significant reduction in the formation of inflammation-driven polypoid, flat and indeterminate dysplasias. This anti-carcinogenic activity of plecanatide was accompanied by activation of cGMP/GC-C signaling mediated inhibition of Wnt/β-catenin signaling and reduced proliferation. Plecanatide also decreased secretion of pro-inflammatory cytokines (IL-6, IL1 TNF), chemokines (MIP-1, IP-10) and growth factors (GCSF and GMCSF) from colon explants derived from mice with acute DSS-induced inflammation. The effect of plecanatide-mediated inhibition of inflammation/dysplasia on endogenous expression of UG and GC-C transcripts was measured in intestinal tissues. Although GC-C expression was not altered appreciably, a statistically significant increase in the level of UG transcripts was detected in the proximal small intestine and colon, potentially due to a reduction in intestinal inflammation and/or neoplasia. Taken together, these results suggest that reductions in endogenous UG, accompanied by dysregulation in GC-C signaling, may be an early event in inflammation-promoted colorectal neoplasia; an event that can potentially be ameliorated by prophylactic intervention with plecanatide.

CONCLUSION

This study provides the first evidence that orally administered plecanatide reduces the multiplicity of inflammation-driven colonic dysplasia in mice, demonstrating the utility for developing GC-C agonists as chemopreventive agents.

Abstract A25: Inhibition or delay of microadenoma development by atorvastatin, naproxen and ED-71 in mice genetically predisposed to colorectal adenomas

Previous studies by this group demonstrate the ability of chemopreventive agents to differentially inhibit morphological subtypes (flat and polypoid) of colorectal adenomas. Recent efforts have focused on the response of microadenomas, a lesion not routinely evaluated by others, to therapeutic intervention. Microadenomas, or dysplastic aberrant crypt foci (ACFs), are direct precursors of colorectal adenomas and represent the earliest microscopic aberration that can be detected prior to colon tumor formation. The goal of the present study was to: 1) characterize the incidence and multiplicity of microadenomas (≤4 crypts) in Apc+/Min-FCCC mice that spontaneously develop multiple colorectal adenomas, and 2) compare the effect of three classes of chemopreventive agents on microadenoma formation. Animals for baseline histological characterization were subjected to colonoscopic examinations at 7 weeks of age (standard time of treatment initiation) and categorized as tumor-free or tumor-bearing. Forty five percent of the Apc+/Min-FCCC mice without gross colon tumors (N=11) possessed microadenomas at baseline, with an overall average of 0.63 ± 0.29 (Mean ± SEM) per mouse. Among mice with gross tumors at baseline (N=10), 30% had microadenomas (0.3 ± 0.16). Results from treatment studies demonstrate that several agents have the ability to modulate microadenoma formation or progression when administered chronically for 14 weeks. First, atorvastatin (100 ppm), a cholesterol-lowering agent, completely eliminated the formation of microadenomas in mice that were free of gross tumors at baseline (as compared to controls, P = 0.007). In addition, a 33% reduction in tumor incidence was observed among atorvastatin-treated animals at 14 weeks as compared to controls (atorvastatin vs. controls: 55.6% vs. 88.5%, P = 0.017). Second, administration of the non-steroidal anti-inflammatory drug naproxen (400 ppm) caused a significant reduction (89.3%) in the multiplicity of microadenomas as compared to that of animals receiving unsupplemented control diet (0.06 ± 0.06 vs. 0.56 ± 0.24, respectively). Inhibition of microadenomas by naproxen translated into a significant reduction in tumor incidence, (naproxen - 64.7%, controls - 100%, P = 0.0076). Third, ED-71 (eldecalcitol; 1α,25-dihydroxy-2β;-(3-hydroxypropyloxy) Vitamin D3), a novel analog of calcitriol, at a dose of 0.1 μg/kg bw, unexpectedly increased the multiplicity of microadenomas in drug-treated mice as compared to controls (0.9 ± 0.22 vs. 0.5 ± 0.25 P = 0.06, respectively). In contrast, ED-71 reduced the mean incidence of adenomas (&gt; 4 crypts) by 47% (ED-71 - 45.5%, controls 92.3%; P = 0.02) and adenoma multiplicity by 47.6% (ED-71 - 1.1 ± 0.39, controls - 2.1 ± 0.72; P &gt; 0.05) in mice that were free of gross tumors at baseline. These data suggest that ED-71 is effective in preventing the progression of microadenomas to adenomas. In summary, these findings demonstrate the importance of evaluating the response of microadenomas to therapy and suggest that microadenomas represent a promising target for chemopreventive intervention.

Supported by CA129467, N01CN43309 and HHSN2610005. * Equal contribution to the abstract.

Citation Format: Wen-Chi L. Chang, Harry S. Cooper, Harvey Hensley, Tianyu Li, Karthik Devarajan, Margie L. Clapper. Inhibition or delay of microadenoma development by atorvastatin, naproxen and ED-71 in mice genetically predisposed to colorectal adenomas. [abstract]. In: Proceedings of the AACR Special Conference on Colorectal Cancer: From Initiation to Outcomes; 2016 Sep 17-20; Tampa, FL. Philadelphia (PA): AACR; Cancer Res 2017;77(3 Suppl):Abstract nr A25.

Imaging Matrix Metalloproteases in Spontaneous Colon Tumors: Validation by Correlation with Histopathology

The use of fluorescent probes in conjunction with white-light colonoscopy is a promising strategy for improving the detection of precancerous colorectal lesions, in particular flat (sessile) lesions that do not protrude into the lumen of the colon. We describe a method for determining the sensitivity and specificity of an enzymatically activated near-infrared probe (MMPSense680) for the detection of colon lesions in a mouse model (APC^+/Min-FCCC) of spontaneous colorectal cancer. Fluorescence intensity correlates directly with the activity of matrix metalloproteinases (MMPs). Overexpression of MMPs is an early event in the development of colorectal lesions. Although the probe employed serves as a reporter of the activity of MMPs, our method can be applied to any fluorescent probe that targets an early molecular event in the development of colorectal tumors.

Angiosarcoma of the Adrenal Gland Treated Using a Multimodal Approach

Angiosarcoma of the adrenal gland is an extremely rare malignancy. We report a case of a 59-year-old female who presented with abdominal pain and profound anemia. A 7 cm enhancing, lipid-poor adrenal mass with calcifications that extended posterior to the vena cava was identified on imaging. Patient underwent right adrenalectomy with retroperitoneal lymph node dissection. Pathology demonstrated angiosarcoma of the adrenal gland. Consolidative treatment included adjuvant radiation and chemotherapy. Patient remains disease free 1.5 years following treatment. Prior reported literature on the diagnosis and management of adrenal angiosarcoma is reviewed.

Molecular profiling of neuroendocrine malignancies to identify prognostic and therapeutic markers: a Fox Chase Cancer Center Pilot Study

BACKGROUND

The rarity of neuroendocrine malignancies limits the ability to develop new therapies and thus a better understanding of the underlying biology is critical.

METHODS

Through a prospective, IRB-approved protocol, patients with neuroendocrine malignancies underwent next-generation sequencing of their tumours to detect somatic mutations (SMs) in 50 cancer-related genes. Clinicopathologic correlation was made among poorly differentiated neuroendocrine carcinomas (NECs/poorly differentiated histology and Ki-67 >20%) and pancreatic neuroendocrine tumours (PanNETs/Ki67 ⩽20%) and non-pancreatic neuroendocrine tumours (NP-NETs/Ki67 ⩽20%).

RESULTS

A total of 77 patients were enrolled, with next-generation sequencing results available on 63 patients. Incidence of SMs was 83% (19 out of 23) in poorly differentiated NECs, 45% (5 out of 11) in PanNETs and 14% (4 out of 29) in NP-NETs. TP53 was the most prevalent mutation in poorly differentiated NECs (57%), and KRAS (30%), PIK3CA/PTEN (22%) and BRAF (13%) mutations were also found. Small intestinal neuroendocrine tumours (Ki67 <2%/n=9) did not harbour any mutations. Prevalence of mutations correlated with higher risk of progression within the previous year (32% (low risk) vs 11% (high risk), P=0.01) and TP53 mutation correlated with worse survival (2-year survival 66% vs 97%, P=0.003).

CONCLUSIONS

Poorly differentiated NECs have a high mutation burden with potentially targetable mutations. The TP53 mutations are associated with poor survival in neuroendocrine malignancies. These findings have clinical trial implications for choice of therapy and prognostic stratification and warrant confirmation.

Abstract 5248: ED-71, an analogue of Vitamin D3, blocks the promotion but not the initiation of colorectal tumors in the Apc+/Min-FCCC mouse model

Results from several studies demonstrate an inverse relationship between circulating levels of Vitamin D and risk of colorectal cancer. Eldecalcitol (1α,25-dihydroxy-2β-(3-hydroxypropyloxy) Vitamin D3; ED-71) is a novel analog of calcitriol, the most active form of Vitamin D3. ED-71 is more potent in stimulating bone remodeling and has been approved in Japan for the treatment of osteoporosis. The goal of this study was to assess the ability of ED-71 to inhibit spontaneous colorectal adenomas in a unique strain of multiple intestinal neoplasia (Apc+/Min-FCCC) mice. Male mice (6 wks of age) were randomized to treatment groups based on colon tumor status (endoscopic confirmation as tumor-free or -bearing) and body weight (bw) and administered: vehicle (MCT), calcitriol (0.25 μg/kg bw), or ED-71 (0.05 or 0.1 μg/kg bw) by gavage. Mice were treated every other day and bws were recorded weekly. After 14 wks of treatment, the small intestines and colons were excised and examined for gross tumors. Colorectal tumors &gt;3 mm in diameter were frozen for gene expression analyses. The remaining tissue was fixed in formalin and processed for histological review. The multiplicity of gross small intestinal tumors in animals treated with ED-71 (both doses) was comparable to that of vehicle-treated controls. In contrast, the multiplicity of small intestinal tumors was elevated 34.6% over that of controls in animals treated with calcitriol (Mean ± SEM: 28.4 ± 2.6 vs. 21.1 ± 2.8, respectively; P = 0.034). The ability of ED-71 to inhibit colon tumorigenesis was evaluated independently in mice with vs. without tumors at treatment initiation. In tumor-bearing mice, neither calcitriol nor ED-71 (both doses) had any significant effect on the multiplicity of colorectal tumors as compared to control mice. However in tumor-free mice, ED-71 (0.1 μg/kg bw) reduced the mean incidence of adenomas (&gt; 4 crypts) by 47% (ED-71 - 45.5%, controls 92.3%; P = 0.02) and the multiplicity by 47.6% (Mean ± SEM: ED-71 - 1.1 ± 0.39, controls - 2.1 ± 0.72; P &gt; 0.05). In contrast, the multiplicity of microadenomas (≤ 4 crypts) was increased in mice treated with ED-71 (0.1 μg/kg bw) as compared to controls (0.9 ± 0.22 vs. 0.5 ± 0.25 P = 0.06, respectively). These findings suggest that ED-71 is effective in preventing the transition of microadenomas to mature adenomas. The lack of an effect of ED-71 on colon tumor development in mice bearing tumors at baseline could be due in part to loss of the Vitamin D receptor in colon adenomas, as confirmed by real-time PCR. Insight into the mechanism by which ED-71 inhibits adenoma development is being gained from analyses of Vitamin D signaling and microRNA expression in treated colonic epithelial cells. These promising data provide support for future studies to determine the potential utility of ED-71 in preventing colorectal cancer in high-risk patients found to be tumor-free during surveillance endoscopy. (Supported by NCI HHSN261201200015I)

Citation Format: Wen-Chi L. Chang, Harry S. Cooper, Esther Kaunga, Lisa Vanderveer, Jing Peng, Suen S. Chen, Margie L. Clapper. ED-71, an analogue of Vitamin D3, blocks the promotion but not the initiation of colorectal tumors in the Apc+/Min-FCCC mouse model. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5248.

Rectal Cancer, Version 2.2015

The NCCN Guidelines for Rectal Cancer begin with the clinical presentation of the patient to the primary care physician or gastroenterologist and address diagnosis, pathologic staging, surgical management, perioperative treatment, posttreatment surveillance, management of recurrent and metastatic disease, and survivorship. The NCCN Rectal Cancer Panel meets at least annually to review comments from reviewers within their institutions, examine relevant new data from publications and abstracts, and reevaluate and update their recommendations. These NCCN Guidelines Insights summarize major discussion points from the 2015 NCCN Rectal Cancer Panel meeting. Major discussion topics this year were perioperative therapy options and surveillance for patients with stage I through III disease.

The value of secondary pathology review

6

Background: Improving the value of cancer care is a major focus for the Alliance of Dedicated Cancer Centers (ADCC). Looking to align with the Institute of Medicine’s (IOM) initiative to “Develop and deploy approaches to identify, learn from, and reduce diagnostic errors and near misses in clinical practice,” the ADCC implemented a study to examine the clinical impact of expert secondary pathology review. The goal of this project was to: 1) demonstrate the value of secondary review of outside pathological specimens by ADCC subspecialty pathologists in identifying significant errors that can potentially impact treatment; and 2) create an opportunity to improve patient cancer care. Methods: All consult slides from patients referred to each ADCC center were reviewed by designated pathologists. Patient-level data for original and revised diagnoses were collected for two months in 2014. Discrepancies were classified as: 1) major - diagnosis changes treatment or surveillance; or, 2) minor - diagnosis does not change affect treatment or surveillance. To verify these assessments, disease-specific, multi-center teams of clinical experts reviewed each discrepant case and provided treatment recommendations for the original and revised diagnoses. Results: A total of 13,109 cases were collected across all ADCC centers and the discrepancy rate was 11% (1,488/1309); 3% (359/13,109) were major and 9% (1,129/13,109) were minor. The most common discrepancy was reclassification of the neoplasm cell type. The highest discrepancy rate was shown in the neuro-oncology and head and neck cases, with a 7% and 4% major discrepancy rate respectively. Conclusions: We identified an overall discrepancy rate of 11%, with 3% of cases leading to a change in treatment or surveillance. This demonstrates the importance of expert pathology review and that secondary pathology review can significantly improve clinical outcomes through precise and accurate pathological diagnoses. As indicated in the recent IOM report, this project further demonstrates that “diagnostic errors may cause harm to patients by preventing or delaying appropriate treatment, providing unnecessary or harmful treatment, or resulting in psychological or financial repercussions.”

Abstract 1600: A multiplexed marker-based algorithm for diagnosis of carcinoma of unknown primary using circulating tumor cells

Abstract: Real-time, single-cell multiplex immunophenotyping of circulating tumor cells (CTCs) is hypothesized to inform diagnosis of tissue of origin in patients with carcinoma of unknown primary (CUP). In 20 to 50% of CUP patients, the primary site remains unidentified, presenting a challenge for clinicians in diagnosis and treatment. Invasive tissue biopsy is the gold standard for diagnosis but improved methodology is needed. We developed a post-CellSearch CTC assay using multiplexed Q-dot or DyLight conjugated antibodies with the goal of detecting multiple markers in single cells within a CTC population. We adapted our approach to size-based CTC enrichment protocols for capturing CTCs and subsequent immunofluorescence (IF) using a minimal set of markers to predict the primary sites for common metastatic tumors. The carcinomas are diagnosed with cytokeratin 7 (CK7), cytokeratin 20 (CK20), thyroid transcription factor 1 (TTF-1), estrogen receptor (ER) or prostate-specific antigen (PSA) as the minimal set of informative markers. IF has been optimized in cultured tumor cells with individual antibodies, then with conjugated antibodies to form a multiplex antibody set. With IF, we evaluated antibodies specific to these 5 markers in lung, breast, colorectal, and prostate cancer cell lines and blood samples from metastatic prostate and breast cancer patients. Our technological advance provides a noninvasive, inexpensive, diagnostic blood test as an adjunct to routine tissue biopsy. Its further implementation requires prospective clinical testing.

Citation Format: Elizabeth M. Matthew, Lanlan Zhou, Namrata Vijayvergia, David T. Dicker, Karen S. Gustafson, Harry S. Cooper, Eric A. Ross, Bora Lim, Ramdane Harouaka, Si-Yang Zheng, Nicholas E. Lamparella, Joseph J. Drabick, Cristina I. Truica, Zhaohai Yang, Wafik S. El-Deiry. A multiplexed marker-based algorithm for diagnosis of carcinoma of unknown primary using circulating tumor cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1600. doi:10.1158/1538-7445.AM2015-1600

Colon cancer, version 3.2014

The NCCN Guidelines for Colon Cancer address diagnosis, pathologic staging, surgical management, perioperative treatment, posttreatment surveillance, management of recurrent and metastatic disease,and survivorship. This portion of the guidelines focuses on the use of systemic therapy in metastatic disease. The management of metastatic colorectal cancer involves a continuum of care in which patients are exposed sequentially to a variety of active agents, either in combinations or as single agents. Choice of therapy is based on the goals of treatment, the type and timing of prior therapy, the different efficacy and toxicity profiles of the drugs, the mutational status of the tumor, and patient preference.

Molecular profiling of neuroendocrine tumors (NETs): The Fox Chase Cancer Center (FCCC) experience

245

Background: The rarity of NETs can limit clinical trial accrual to develop new therapies. Given fewer approved treatments, a better understanding of underlying biology is critical to development of and assignment of patients (pts) to clinical trials. Methods: Pts with NETs (excluding small/large cell lung cancer) of all grades at FCCC were enrolled onto a prospective IRB approved protocol that utilized an NGS platform to detect somatic mutations (SM) in 50 cancer-related genes (Cancer Code) on archived tissue from primary or metastatic sites. Genes tested included ABL1, AKT1, ALK, APC, ATM, BRAF, CDH1, CDKN2A, CSF1R, CTNNB1, EGFR, ERBB2, ERBB4, EZH2, FBXW7, FGFR1, FGFR2, FGFR3, FLT3, GNA11, GNAQ, GNAS, HNF1A, HRAS, IDH1, IDH2, JAK2, JAK3, KDR, KIT, KRAS, MET, MLH1, MPL, NOTCH1, NPM1, NRAS, PDGFRA, PIK3CA, PTEN, PTPN11, RB1, RET, SMAD4, SMARCB1, SMO,SRC, STK11, TP53 and VHL. Review of pathology specimens for grade and Ki -67 was also performed. Results: Thirty-nine pts (median age 59 y, males 46%) were enrolled from October 2013 to July 2014. Gene profiling results are available on thirty-five pts. Ki-67 score was reviewed for 31/35 tumors. 6 (20%) pts had high grade (HG) tumors (Ki-67 > 20%) and 25 (80%) had low/intermediate grade (LIG) tumors (Ki-67 ≤20%). Thirteen (37%) pts were found to have SMs and 22 (63%) did not, with 4 (12%) pts’ tumors having >1 SMs (2 HG and 2 LIG tumors). Incidence of SM was 41% (12/29) in Caucasians, 16% (1/6) in other races, 46% (6/13) in smokers and 30% (6/20) in non-smokers. Incidence of SM was 24% (6/25) in LIG NETs and 84% (5/6) in the HG NETs. Among HG tumors, 66% (4/6) harbored TP53 gene mutation and 33% (2/6) were BRAF mutation positive. Conclusions: Tumor-specific mutations are seen in a minority of low grade NETs but are common in high grade tumors. Interestingly, no mutations were identified in pts with unknown primary. Analysis of clinical outcomes based on treatment received is ongoing to assess for possible prognostic/therapeutic implications of these mutations. [Table: see text]

Neoadjuvant chemoradiation (NACRT) and the prognostic effect of surgical margin (SM) status in pancreatic adenocarcinoma (PAC)

407

Background: Many studies have associated a R0 resection to have significantly improved survival compared with a R1 resection in PAC. Patients (pts) who undergo NACRT often go to surgery 4-8 weeks after the end of therapy, before the effects of NACRT can be fully manifested. The goal of this study is to evaluate if a positive SM (+SM) after NACRT has the same poor prognosis as a +SM after upfront surgery. Methods: After IRB approval, we retrospectively reviewed all cases of surgically resected PAC at a single institution from Dec 1996 to Jan 2014. Pts were stratified by receipt of NACRT as well as by SM status. We excluded pts treated with palliative intent, metastatic disease at presentation, death within 90 days of surgery, and biliary or ampullary tumors. The primary endpoint was overall survival (OS). We assessed the relationship between pt and tumor variables with treatment/margin combination using Chi-squared tests. OS was examined using Kaplan-Meier curves, and we tested association with treatment/margin using log-rank tests. Results: A total of 213 pts met inclusion criteria; 111 received upfront surgery (group I) with 94 (85%) receiving adjuvant chemotherapy or CRT and 102 received NACRT (group II) with either concurrent 5-fluorouracil (n=18) or gemcitabine (n=84). There were 31 pts with +SM in group I and 29 pts in group II. Pt demographics were balanced. There was more vessel involvement in group II (81%) at diagnosis than group I (11%) (p<0.01) with a trend towards improved OS in group II vs group I (p=0.09). Pathological evaluation revealed more PNI (61% vs 42%, p<0.01) and more lymph node positivity (71% vs 33%, p<0.01) in group I vs group II, respectively. Median OS for group I SM+/SM- and group II SM+/SM- were 15/25 months and 26/32 months respectively. OS is significantly improved with a negative SM (-SM) compared with a +SM (p<0.01). If the SM is positive, pts in group II had improved OS compared with group I (p=0.02). OS was not significantly different for group II +SM vs group I –SM (p=0.34). Conclusions: The negative impact of a +SM on survival is partially mitigated by NACRT. This data further supports the use of NACRT, although it is limited by its retrospective nature and small sample size.

Increased time from neoadjuvant chemoradiation to surgery is associated with higher pathologic complete response rates in esophageal cancer

BACKGROUND

The interval between neoadjuvant chemoradiation treatment and surgery has been described as an important predictor of pathologic response to therapy in nonesophageal cancer sites. We retrospectively reviewed our experience with patients who underwent neoadjuvant chemoradiation and esophagectomy to better understand the impact of the timing of surgery on pathologic complete response rates in esophageal cancer.

METHODS

Two hundred thirty-one sequentially treated patients from 2000 to 2011 were identified for this study; 88 of these patients completed neoadjuvant chemoradiation followed by esophagectomy at our institution. The interval between completion of chemoradiation and surgery was calculated for each patient. The patients were categorized into quartiles and also into 3-week interval groups. Treatment factors and surgical morbidity data, including the estimated blood loss and length of operative stay, were also assessed.

RESULTS

Quartiles for the neoadjuvant chemoradiation to surgery interval were less than 45 days, 46 to 50 days, 51 to 63 days, and 64+ days. Corresponding pathologic complete response rates were 12.5%, 20.0%, 22.7%, and 40.9% (p = 0.03). Results for 3-week intervals were similar (p = 0.02). There was no association between increasing time interval between the ending of neoadjuvant chemoradiation to surgery and length of stay longer than 2 weeks.

CONCLUSIONS

A longer interval between completion of neoadjuvant chemoradiation and surgery was associated with higher pathologic complete response rates without an impact on surgical morbidity.

Localized colon cancer, version 3.2013: featured updates to the NCCN Guidelines

The NCCN Clinical Practice Guidelines in Oncology for Colon Cancer begin with the clinical presentation of the patient to the primary care physician or gastroenterologist and address diagnosis, pathologic staging, surgical management, perioperative treatment, patient surveillance, management of recurrent and metastatic disease, and survivorship. The NCCN Colon Cancer Panel meets annually to review comments from reviewers within their institutions and to reevaluate and update their recommendations. In addition, the panel has interim conferences as new data necessitate. These NCCN Guidelines Insights summarize the NCCN Colon Cancer Panel's discussions regarding the treatment of localized disease for the 2013 update of the guidelines.

Neoadjuvant chemoradiation and duration of chemotherapy before surgical resection for pancreatic cancer: does time interval between radiotherapy and surgery matter?

BACKGROUND

Neoadjuvant chemoradiation and chemotherapy provided for borderline or locally advanced, potentially resectable pancreatic adenocarcinoma improves resectability rates. Response to therapy is also an important prognostic factor. There are no data in the literature regarding optimal time interval or duration of chemotherapy after chemoradiation before surgery, and pathologic response rates. Using our database, we evaluated these relationships and the effect on overall and progression-free survival.

METHODS

We retrospectively analyzed the records of 83 patients who underwent neoadjuvant chemoradiation for locally advanced, potentially resectable, and borderline resectable pancreatic cancers before definitive resection. We divided patients into three groups according to time interval between completion of chemoradiation and resection: group A (0-10 weeks), group B (11-20 weeks), and group C (>20 weeks). After chemoradiation, patients underwent ongoing chemotherapy before resection. Pathologic response was defined as major (>95% fibrosis), partial (50-94% fibrosis), or minor (<50% fibrosis).

RESULTS

There were 56 patients in group A, 17 patients in group B, and 10 patients in group C. Patients in groups B and C were significantly more likely to experience a major response than group A (p < 0.013). Patients in group C had significantly increased median progression-free and overall survival (p < 0.05). Multivariable classification and regression tree analysis demonstrated pathologic response to be the only significant factor in overall survival.

CONCLUSIONS

Patients who underwent a prolonged time interval after neoadjuvant chemoradiation with ongoing chemotherapy were more likely to have an improved pathologic response at time of surgical resection, which was associated with improved median overall survival.

Metastatic colon cancer, version 3.2013: featured updates to the NCCN Guidelines

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Colon Cancer begin with the clinical presentation of the patient to the primary care physician or gastroenterologist and address diagnosis, pathologic staging, surgical management, perioperative treatment, patient surveillance, management of recurrent and metastatic disease, and survivorship. The NCCN Colon Cancer Panel meets annually to review comments from reviewers within their institutions and to reevaluate and update their recommendations. In addition, the panel has interim conferences as new data necessitate. These NCCN Guidelines Insights summarize the NCCN Colon Cancer Panel's discussions surrounding metastatic colorectal cancer for the 2013 update of the guidelines. Importantly, changes were made to the continuum of care for patients with advanced or metastatic disease, including new drugs and an additional line of therapy.

Quantification of excision repair cross-complementing group 1 and survival in p16-negative squamous cell head and neck cancers

PURPOSE

Multimodality treatment of squamous cell carcinoma of the head and neck (SCCHN) often involves radiotherapy and cisplatin-based therapy. Elevated activity of DNA repair mechanisms, such as the nucleotide excision repair (NER) pathway, of which ERCC1 is a rate-limiting element, are associated with cisplatin and possibly RT resistance. We have determined excision repair cross-complementing group 1 (ERCC1) expression in human papillomavirus (HPV)-negative SCCHN treated with surgery [± adjuvant radiotherapy/chemoradiation (CRT)].

EXPERIMENTAL DESIGN

We assessed ERCC1 protein expression in archival tumors using immunofluorescence staining and automatic quantitative analysis (AQUA) with three antibodies to ERCC1 (8F1, FL297, and HPA029773). Analysis with Classification and Regression Tree (CART) methods ascertained the cutoff points between high/low ERCC1 expression. Multivariable analysis adjusted for age, T, and N stage. Kaplan-Meier curves determined median survival. ERCC1 expression at initial tumor presentation and in recurrent disease were compared. Performance characteristics of antibodies were assessed.

RESULTS

ERCC1 low/high groups were defined on the basis of AQUA analysis with 8F1/2009, FL297, and HPA029773. Among patients treated with surgery plus adjuvant radiotherapy/CRT, longer median survival was observed in ERCC1-low versus ERCC1-high tumors (64 vs. 29 months; P = 0.02; HPA029773). Data obtained with HPA029773 indicated no survival difference among patients treated only with surgery. Recurrent cancers had lower ERCC1 AQUA scores than tumors from initial presentation. Extensive characterization indicated optimal specificity and performance by the HPA029773 antibody.

CONCLUSIONS

Using AQUA, with the specific ERCC1 antibody HPA029773, we found a statistical difference in survival among high/low-ERCC1 tumors from patients treated with surgery and adjuvant radiotherapy.

Rectal cancer

These NCCN Clinical Practice Guidelines in Oncology provide recommendations for the management of rectal cancer, beginning with the clinical presentation of the patient to the primary care physician or gastroenterologist through diagnosis, pathologic staging, neoadjuvant treatment, surgical management, adjuvant treatment, surveillance, management of recurrent and metastatic disease, and survivorship. This discussion focuses on localized disease. The NCCN Rectal Cancer Panel believes that a multidisciplinary approach, including representation from gastroenterology, medical oncology, surgical oncology, radiation oncology, and radiology, is necessary for treating patients with rectal cancer.

Differential response of flat and polypoid colitis-associated colorectal neoplasias to chemopreventive agents and heterocyclic amines

Individuals with ulcerative colitis face an increased risk of developing colorectal cancer and would benefit from early chemopreventive intervention. Results from preclinical studies in the mouse model of dextran sulfate sodium-induced colitis demonstrate that flat and polypoid colitis-associated dysplasias arise via distinct genetic pathways, impacted by the allelic status of p53. Furthermore, flat and polypoid dysplasias vary in their response to induction by the heterocyclic amine 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and inhibition by 5-aminosalicylic acid, a common therapy for the maintenance of colitis patients. These data suggest that use of combination therapy is essential for the optimal inhibition of colitis-associated colorectal cancer.

Evaluating the impact of a clinical universal mismatch repair screening initiative

194

Background: Immunohistochemistry (IHC)-based universal mismatch repair (UMMR) screening of incident colorectal (CRC) and endometrial (EC) tumors for deficient MMR (dMMR) associated with Lynch syndrome (LS) is supported by expert recommendations and is cost-effective. Heterogeneity in the approach to implementation of UMMR screening nationwide has been observed, suggesting knowledge gaps that could adversely impact anticipated outcomes. Studies of clinical UMMR screening can inform efforts to optimize implementation in the real world setting. Methods: In September 2011, Fox Chase Cancer Center (FCCC) began UMMR screening of incident (surgical) CRC/EC tumors. Providers were emailed a tailored UMMR Results letter intended to facilitate discussion of hereditary cancer risks and for distribution to patients. Content supported genetics consultation for an abnormal UMMR screen or for high-risk history (Hx) regardless of MMR status (i.e., personal Hx of any cancer; or 1st/2nd degree relative with a LS cancer and/or cancer <50). For comparison, clinical data on all CRC/EC surgical cases 3 months prior to implementation of UMMR screening were extracted from the medical record. Results: 55 surgeries for CRC/EC occurred in the 3 months pre-implementation (PRE) and 130 in the 9 months post-implementation (POST). 1 yr PRE and POST data will be presented at the 2012 Quality Symposium. Conclusions: The UMMR screening initiative greatly improved patient outcomes. Provider referral and documentation behavior was highly responsive to an abnormal screening result, but not high-risk cancer history alone. [Table: see text]

Anal Carcinoma, Version 2.2012: featured updates to the NCCN guidelines

The workup and management of squamous cell anal carcinoma, which represents the most common histologic form of the disease, are addressed in the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Anal Carcinoma. These NCCN Guidelines Insights provide a summary of major discussion points of the 2012 NCCN Anal Carcinoma Panel meeting. In summary, the panel made 4 significant changes to the 2012 NCCN Guidelines for Anal Carcinoma: 1) local radiation therapy was added as an option for the treatment of patients with metastatic disease; 2) multifield technique is now preferred over anteroposterior-posteroanterior (AP-PA) technique for radiation delivery and the AP-PA technique is no longer recommended as the standard of care; 3) PET/CT should now be considered for radiation therapy planning; and 4) a section on risk reduction was added to the discussion section. In addition, the panel discussed the use of PET/CT for the workup of anal canal cancer and decided to maintain the recommendation that it can be considered in this setting. They also discussed the use of PET/CT for the workup of anal margin cancer and for the assessment of treatment response. They reaffirmed their recommendation that PET/CT is not appropriate in these settings.

Effect of increased time from chemoradiation to surgery on the pathologic complete response rate in patients with esophageal cancer

84

Background: Studies have demonstrated that pathologic complete response (pCR) in patients undergoing tri-modality treatment for esophageal cancer predicts for decreased local and distant recurrence, as well as increased survival. Increased time from chemoradiation (CRT) to surgery has been shown to increase pCR rates in rectal cancer. This study assessed the effect of the time between the end of CRT and surgery on pCR rates in esophageal cancer.

Methods: Clinical records identified 231 patients with resectable esophageal cancer who were treated with CRT from 2000 to 2011, of which 89 underwent subsequent surgery. The records were analyzed for predictors of pCR. Univariate and multivariable analyses were used to determine the significance of all predictors of pCR.

Results: Of 89 patients completing trimodality therapy, 76 were male, and the median age was 61 years (range=36-80). Adenocarcinomas comprised 75 patients, and 14 were squamous cell carcinomas. Nine patients had T1/T2 lesions and 80 patients had T3/T4 lesions; 68 patients had node positive tumors. 72 patients received 5FU-based therapy and 17 patients received carboplatin-based therapy. The median radiation dose was 5040 cGy (720-6000) and median follow-up was 24 months. Overall, pCR was seen in 21 patients (24%). The median time from CRT to surgery for a pCR was 102 days vs. 87 days for less than a pCR (p=0.06). By quartile of time from CRT to surgery, pCRs were 18% for <81 days, 13% for 81-88 days, 18% for 89-102 days, and 45% for 103+ days (p=0.05). Multivariable logistic regression showed a trend towards a difference in pCR rates by interval quartile (p=0.06); OR for the highest vs lowest quartile was 5.3 (95% CI=1.1 to 25.6). T stage, N stage, histology, radiation dose and type of chemotherapy were not predictive of a pCR.

Conclusions: In this retrospective study, increased time between CRT and surgery was associated with a trend toward increased pCR rates; patients in the longest interval quartile (103+ days) had more pCRs than patients in the shortest interval quartile (<81 days). These data suggest further evaluation of time from CRT to surgery is warranted.