Sidedness is prognostic in locoregional colon cancer: an analysis of 9509 Australian patients

BACKGROUND/AIM

Right sided colon cancer (RsCC) is proposed to be a distinct disease entity to left sided colon cancer (LsCC). We seek to confirm primary tumour location as an independent prognostic factor in locoregional colorectal cancer.

METHODS

All patients with stage I - III primary adenocarcinoma of colon were identified from the New South Wales (NSW) clinical cancer registry (2006-2013). Primary tumour location (RsCC vs LsCC) survival analyses were conducted using the Kaplan-Meier method, and adjusted hazard ratios for 5-year all-cause mortality (OS) and 5-year cancer specific mortality (CSS) were obtained using Cox proportional hazards regression.

RESULTS

We identified 9509 patients including 5051 patients with RsCC and 4458 with LsCC. Patients with RsCC were more likely to be older, female, have a higher Charlson comorbidity index, and have worse tumour prognostic factors. In univariate analysis of all stages combined, those patients with RsCC had a worse overall survival (OS, HR 1.20 95% CI 1.11-1.29, p < 0.0001), although this was not significant in the multivariate analysis (HR 0.96 95% CI 0.89-1.04, p = 0.35). Stage I patients with RsCC had a trend to improved OS (multivariate HR 0.84 95% CI 0.69-1.01, p = 0.07) and a significantly improved CSS (multivariate HR 0.51 95% CI 0.35-0.75, p = 0.0006). In stage II patients with RsCC there was a significantly improved OS (multivariate HR 0.85 95% CI 0.75-0.98, p = 0.02) and CSS (multivariate HR 0.59 95% CI 0.45-0.78, p = 0.0002) compared to LsCC. In stage III patients, those with RsCC had a worse OS (multivariate HR 1.13 95% CI 1.01-1.26, p = 0.032) and a trend to worse CSS (multivariate HR 1.12 95% CI 0.94-1.33, p = 0.22).

CONCLUSIONS

Primary tumour location is an important prognostic factor in locoregional colon cancer with an effect that varies by stage. RsCC is associated with lower all-cause mortality in stage II, and higher all-cause mortality in stage III.

Droplet Digital PCR Based Androgen Receptor Variant 7 (AR-V7) Detection from Prostate Cancer Patient Blood Biopsies

Androgen receptor splice variant V7 (AR-V7) was recently identified as a valuable predictive biomarker in metastatic castrate-resistant prostate cancer. Here, we report a new, sensitive and accurate screen for AR-V7 mRNA expression directly from circulating tumor cells (CTCs): We combined EpCAM-based immunomagnetic CTC isolation using the IsoFlux microfluidic platform with droplet digital polymerase chain reaction (ddPCR) to analyze total AR and AR-V7 expression from prostate cancer patients CTCs. We demonstrate that AR-V7 is reliably detectable in enriched CTC samples with as little as five CTCs, even considering tumor heterogeneity, and confirm detection of AR-V7 in CTC samples from advanced prostate cancer (PCa) patients with AR-V7 detection limited to castrate resistant disease status in our sample set. Sensitive molecular analyses of circulating tumor cells (CTCs) or circulating tumor nucleic acids present exciting strategies to detect biomarkers, such as AR-V7 from non-invasive blood samples, so-called blood biopsies.

The Potential Value of Immunotherapy in Colorectal Cancers: Review of the Evidence for Programmed Death-1 Inhibitor Therapy

Colorectal cancers (CRCs) have been identified as potential targets for immunotherapy with programmed cell death (PD)-1 inhibitors. English-language publications from MedLine and Embase that evaluated PD-1/PD ligand 1 (PD-L1) in the CRC tumor microenvironment and clinical trials that assessed PD-1 inhibitors were included. Sixteen abstracts were screened. Fifteen met the inclusion criteria. After review of the full texts, this resulted in a final reference list of 8 studies eligible for review. Five studies that assessed PD-1/PD-L1 in CRC and 3 trials that assessed PD-1 inhibitors were included. PD-1-positive (PD-1⁺) tumor-infiltrating lymphocytes and PD-L1⁺ cancer cells featured more prominently in high-level microsatellite instability (MSI-H) CRCs compared with microsatellite stable (MSS) CRCs, except in 1 study in which PD-L1 expression was higher in MSS CRCs. In the 3 trials that assessed PD-1 inhibitor, all 3 studies recruited patients with metastatic CRC (mCRC). One study also included patients with recurrent CRC. The objective response according to the Response Evaluation Criteria in Solid Tumors criteria was 0% (19 CRC patients with unknown microsatellite instability status) in the nivolumab study. In the pembrolizumab study, the objective response to PD-1 inhibitor was 40% and 0% in patients with MSI-H and MSS mCRC, respectively (10 patients in the MSI-H group, 18 patients in the MSS group). Seventy-eight percent of the patients in the MSI-H mCRC group compared with 11% in the MSS mCRC group (P < .005) showed no further disease progression at 12 weeks. In the nivolumab with or without ipilimumab study, objective partial response at 12 weeks to PD-1 inhibitor with or without cytotoxic T-lymphocyte-associated protein 4 inhibitor was 25.5% to 33.3% and 5% in the MSI-H and MSS groups, respectively (100 patients in the MSI-H group, 20 patients in the MSS group). Clinical trials that assessed PD-1 inhibitor immunotherapy in patients with CRC have recruited only small cohorts of patients with mCRC. Studies on the tumor microenvironment have been on the basis of archival specimens with different antibody PD-1 and PD-L1 preparations for immunohistochemistry, independent from immunotherapy trials. Immunotherapy with PD-1 therapy has potential benefit for immunogenic MSI-H CRCs whereas there is no evidence to date to suggest immunotherapy benefit in MSS CRCs. The available data are limited, and there is no information on non-mCRCs. Future trials are under way to determine its benefits.

Abstract 1942: Change in serum microRNA expression during neoadjuvant chemoradiation for rectal cancer

Introduction

MicroRNAs (miRNA) expression may change with treatment and influence responses in locally advanced rectal cancer (LARC) making them potentially useful predictive and prognostic biomarkers. We investigated 112 miRNAs in serum during chemoradiation for LARC.

Methods

Twenty-one patients with LARC treated with neoadjuvant chemoradiation were prospectively recruited for the study. Serum was collected at three time-points: 1) at diagnosis (baseline), 2) at three weeks into treatment and 3) at completion of chemoradiation (pre-surgery). Serum was also collected from 10 healthy controls. RNA extraction was performed using the Norgen™ total RNA purification kit. Reverse transcription and pre-amplification were performed as per the Taqman™ OpenArray MicroRNA Panels manufacturer's instructions. miRNA array qPCR was performed on 112 miRNA targets using the QuantStudio™ 12K platform. Differentially expressed miRNAs were identified using the delta-delta-Ct method, using the endogenous U6 snRNA as the control. Analysis was performed in R, using paired t-statistics, and the Benjamini-Hochberg False Discovery Rate for multiple hypothesis testing adjustment, with a threshold q&lt;0.05 for significant differential expression. Enriched KEGG pathways were identified using DIANA, based on verified gene targets of each miRNA from Tarbase.

Results

We identified 12 miRNAs that were significantly differentially expressed between patients and matched controls. The strongest differences were observed between patient samples at baseline and completion of chemoradiation, where eight miRNAs decreased in expression: hsa-miR-101, hsa-miR-130a, hsa-miR-130b, hsa-miR-223, hsa-miR-27a, hsa-miR-628-5p, hsa-miR-630 and hsa-miR-720, all with fold change &gt; 3-fold. These genes are known to target key rectal cancer genes such as SMAD4, BCL2, MSH2 and TGFBR2. An additional three miRNAs changed significantly between baseline and week 3: hsa-miR-135b*, hsa-miR-375 and hsa-miR-629. All except hsa-miR-135b* became less abundant.

Conclusions

Ten differentially expressed miRNAs appear downregulated during chemoradiation in LARC. These miRNAs have been implicated in cell proliferation, the epithelial-mesenchymal transition and radiation resistance. Further work will be undertaken to understand the functional implications of these changes.

Citation Format: Stephanie H. Lim, Paul De Souza, Wei Chua, Weng Ng, Benjamin Harris, Mark J. Cowley, Kevin Spring. Change in serum microRNA expression during neoadjuvant chemoradiation for rectal cancer. [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 1942.

Management of asymptomatic primary tumours in stage IV colorectal cancer: Review of outcomes

AIM: To compare outcomes for patients presenting with stage IV colorectal cancer and an asymptomatic primary tumour, undergoing primary tumour resection (PTR) plus palliative chemotherapy vs primary chemotherapy up-front.

METHODS: A literature search was conducted using MEDLINE and EMBASE. The primary outcome was overall survival. Secondary outcomes included perioperative mortality, morbidity and delayed surgical intervention rates in patients undergoing PTR and subsequent complication rates in patients with an un-resected primary tumour. Tertiary outcomes included impact on systemic treatment and identification of prognostic factors relevant for survival in this cohort.

RESULTS: Twenty non-randomised studies met the inclusion criteria. Eleven studies included comparative overall survival data. Three studies showed an overall survival advantage for PTR, 7 studies showed no statistically significant advantage, and 1 study showed a significant worsening in survival in the surgical group. The perioperative mortality rate ranged from 0% to 8.5%, and post-operative morbidity rate from 10% to 35%, mainly minor complications that did not preclude subsequent chemotherapy. The rate of delayed primary-tumour related symptoms, most commonly obstruction, in patients with an un-resected primary tumour ranged from 3% to 46%. The strongest independent poor prognostic factor was extensive hepatic metastases, in addition to poor performance status, M1b stage and non-use of modern chemotherapy agents.

CONCLUSION: Based on the current literature, both PTR and up front chemotherapy appear appropriate initial management strategies, with a trend towards an overall survival advantage with PTR. The procedure has a low post-operative mortality, and most complications are transient and minor. The results of recruiting randomised trials are eagerly anticipated.

Upregulated Polo-Like Kinase 1 Expression Correlates with Inferior Survival Outcomes in Rectal Cancer

BACKGROUND

Human polo-like kinase 1 (PLK1) expression has been associated with inferior outcomes in colorectal cancer. Our aims were to analyse PLK1 in rectal cancer, and its association with clinicopathological variables, overall survival as well as tumour regression to neoadjuvant treatment.

METHODS

PLK1 expression was quantified with immunohistochemistry in the centre and periphery (invasive front) of rectal cancers, as well as in the involved regional lymph nodes from 286 patients. Scores were based on staining intensity and percentage of positive cells, multiplied to give weighted scores from 1-12, dichotomised into low (0-5) or high (6-12).

RESULTS

PLK1 scores in the tumour periphery were significantly different to adjacent normal mucosa. Survival analysis revealed that low PLK1 score in the tumour periphery had a hazard ratio of death of 0.59 in multivariate analysis. Other predictors of survival included age, tumour depth, metastatic status, vascular and perineural invasion and adjuvant chemotherapy. There was no statistically significant correlation between PLK1 score and histological tumour regression in the neoadjuvant cohort.

CONCLUSION

Low PLK1 score was an independent predictor of superior overall survival, adjusting for multiple clinicopathological variables including treatment.

Gastrointestinal perforation in metastatic colorectal cancer patients with peritoneal metastases receiving bevacizumab

AIM: To investigate the safety and efficacy of adding bevacizumab to first-line chemotherapy in metastatic colorectal cancer patients with peritoneal disease.

METHODS: We compared rates of gastrointestinal perforation in patients with metastatic colorectal cancer and peritoneal disease receiving first-line chemotherapy with and without bevacizumab in three distinct cohorts: (1) the AGITG MAX trial (Phase III randomised clinical trial comparing capecitabine vs capecitabine and bevacizumab vs capecitabine, bevacizumab and mitomycinC); (2) the prospective Treatment of Recurrent and Advanced Colorectal Cancer (TRACC) registry (any first-line regimen ± bevacizumab); and (3) two cancer centres in New South Wales, Australia [Macarthur Cancer Therapy Centre and Liverpool Cancer Therapy Centre (NSWCC) from January 2005 to Decenber 2012, (any first-line regimen ± bevacizumab). For the AGITG MAX trial capecitabine was compared to the other two arms (capecitabine/bevacizumab and capecitabine/bevacizumab/mitomycinC). In the AGITG MAX trial and the TRACC registry rates of gastrointestinal perforation were also collected in patients who did not have peritoneal metastases. Secondary endpoints included progression-free survival, chemotherapy duration, and overall survival. Time-to-event outcomes were estimated using the Kaplan-Meier method and compared using the log-rank test.

RESULTS: Eighty-four MAX, 179 TRACC and 69 NSWCC patients had peritoneal disease. There were no gastrointestinal perforations recorded in either the MAX subgroup or the NSWCC cohorts. Of the patients without peritoneal disease in the MAX trial, 4/300 (1.3%) in the bevacizumab arms had gastrointestinal perforations compared to 1/123 (0.8%) in the capecitabine alone arm. In the TRACC registry 3/126 (2.4%) patients who had received bevacizumab had a gastrointestinal perforation compared to 1/53 (1.9%) in the chemotherapy alone arm. In a further analysis of patients without peritoneal metastases in the TRACC registry, the rate of gastrointestinal perforations was 9/369 (2.4%) in the chemotherapy/bevacizumab group and 5/177 (2.8%) in the chemotherapy alone group. The addition of bevacizumab to chemotherapy was associated with improved progression-free survival in all three cohorts: MAX 6.9 m vs 4.9 m, HR = 0.64 (95%CI: 0.42-1.02); P = 0.063; TRACC 9.1 m vs 5.5 m, HR = 0.61 (95%CI: 0.37-0.86); P = 0.009; NSWCC 8.7 m vs 6.8 m, HR = 0.75 (95%CI: 0.43-1.32); P = 0.32. Chemotherapy duration was similar across the groups.

CONCLUSION: Patients with peritoneal disease do not appear to have an increased risk of gastrointestinal perforations when receiving first-line therapy with bevacizumab compared to systemic therapy alone.

Circulating tumour cells and the epithelial mesenchymal transition in colorectal cancer

Circulating tumour cells (CTCs) hold great potential as liquid biopsies to prognosticate disease and guide treatment in colorectal cancer. However, their emerging role in determining the molecular phenotype of tumour metastasis carries even more promising clinical use in the provision of comprehensive biomarker detection for targeted therapies and determination of drug resistance. The isolation of CTCs is technology dependent, and in the case of epithelial cell adhesion molecule-based platforms, the ability to detect cells that have undergone the epithelial to mesenchymal transition (EMT) is ineffective. CTCs displaying a mesenchymal phenotype are believed to have an increased metastatic potential. The rarity of CTCs provides another challenge in the enumeration of these cells. The future will likely involve the analysis of individual CTCs at any stage of the EMT in order to provide real-time phenotypic and molecular snapshots capable of tracking the dynamic evolution of tumour progression over time.

Effect of neoadjuvant chemoradiation on tumor-infiltrating/associated lymphocytes in locally advanced rectal cancers

BACKGROUND

Lymphocytes and natural killer cells (NK) appear to be important in colorectal cancer. Their role in chemoradiotherapy for rectal cancers is unclear. We evaluated T-lymphocytes (CD3), sub-groups CD4 and CD8, and NK cells (CD56+CD57) in normal and rectal tumor tissues pre- and post-chemoradiotherapy, and investigated their relationship to tumor regression grade, disease-free survival and pathological stage.

MATERIALS AND METHODS

Tissue microarrays from colonoscopic biopsies, resection specimens and normal tissues, from 52 patients, were immunostained.

RESULTS

NK cell counts were significantly lower in tumor samples compared to normal tissues (p=0.007). T-lymphocyte counts were higher in post-treatment compared to pre-treatment samples (p=0.025), specifically in the CD8 subgroup after long-course treatment. The results suggested an association between post-treatment CD8 and NK cell counts with higher tumor regression. No associations were found with regard to stage or disease-free survival.

CONCLUSION

NK cell counts were significantly reduced in rectal cancers compared to normal tissues, while total T-lymphocyte counts increased post-chemoradiotherapy. Both appeared important in tumor regression.

Predictive and prognostic value of circulating tumor cell detection in lung cancer: a clinician's perspective

There is increasing evidence for the use of circulating tumor cells (CTCs) as a "liquid biopsy" for early detection of lung cancer recurrence, prognosticating disease and monitoring treatment response. Further, CTC molecular analysis and interrogation of single cells hold significant potential in providing insights into tumor biology and the metastatic process. Ongoing research will likely see the translation of CTCs as a prognostic and predictive biomarker in both small cell, and non-small cell, lung cancer to routine clinical practice.

The efficacy and safety outcomes of bevacizumab and systemic therapy in metastatic colorectal cancer patients with peritoneal disease in the AGITG MAX clinical trial and in nontrial patients in two cancer centers

595

Background: Metastatic colorectal cancer with peritoneal disease (PmCRC) represents a phenotype that may derive a greater clinical benefit from bevacizumab (BEV) due to the effect of VEGF on peritoneal spread and ascites production. However, there is concern of greater adverse events, in particular GI perforations. We investigated the clinical benefit and safety of adding BEV to chemotherapy in PmCRC in clinical trial and nontrial populations. Methods: We compared PFS and OS in PmCRC patients receiving first-line chemotherapy with and without BEV in: (1) the AGITG MAX trial (capecitabine [CAP] vs CAP/BEV +/- mitomycin C) and (2) two cancer centers in New South Wales between Jan 2005 and Dec 2012 (any regimen +/- BEV). Secondary endpoints included chemotherapy duration and GI adverse events. Time to event outcomes were estimated using the method of Kaplan-Meier and comparisons made using the logrank test. Proportional hazards models were used to obtain hazard ratios for regression analysis. Results: See Table. 84 MAX and 69 nontrial pts had PmCRC and there was a 37% reduction in the risk of progression in those receiving BEV, which is similar when compared to the nonperitoneal disease pts (HR= 0.63 95% CI 0.52-0.79 p value < 0.001). OS in the PmCRC group was significantly worse than the nonperitoneal group (14.3 months vs 18.8 months p value = 0.02). Chemotherapy duration was similar across the groups. The rate of notable GI adverse events, including GI perforation was not increased in the PmCRC group receiving BEV in either cohort. One pt had a GI perforation after receiving CAP+BEV. Conclusions: Pts with mCRC and peritoneal disease receiving first-line therapy in trial and nontrial populations appear to derive a similar proportional benefit when BEV is added to systemic therapy without an increase in GI adverse events. However, this subgroup of patients continues to have a worse prognosis. [Table: see text]

Circulating tumour cells and circulating free nucleic acid as prognostic and predictive biomarkers in colorectal cancer

The detection of circulating tumour cells or circulating free tumour nucleic acids can potentially guide treatment and inform prognosis in colorectal cancer using minimally invasive "liquid biopsies". Current literature supports the notion that high circulating tumour cell counts or presence of tumour nucleic acid correlate with inferior clinical outcomes for patients, but they are not yet part of routine clinical care. Future research evolves around the examination of the molecular phenotype of circulating tumour cells. The key unanswered areas include differentiating between circulating tumour cell presence and their proliferative capacity and dormancy, identifying tumour heterogeneity and understanding the epithelial-mesenchymal transition.

Predicting chemotherapeutic response and toxicity in colorectal cancer

SUMMARY While treatment for colorectal cancer has evolved significantly over the past 10 years with the introduction of active chemotherapeutic agents and targeted therapies, this has been at the cost of increased toxicity for patients; and significant financial burden for governments and patients. Predicting clinical outcomes, especially given the largely elderly patient population involved, is therefore paramount. This review seeks to summarize existing data regarding the prediction of response and toxicity to chemotherapy agents currently used in the treatment of colorectal cancer.

Systemic inflammation and prediction of chemotherapy outcomes in patients receiving docetaxel for advanced cancer

BACKGROUND

Inflammatory markers are strong prognostic factors for survival in a variety of cancers. This study aimed to investigate the relationships between known inflammatory markers and their ability to predict overall survival (OS) in patients receiving docetaxel therapy.

METHODS

Sixty-eight patients with advanced cancer were enrolled in a clinical trial of single agent docetaxel from 2000 to 2002. Inflammation was measured using baseline cytokine concentrations, acute phase reactant proteins and white blood cell counts. The neutrophil/lymphocyte ratio (NLR) and Glasgow Prognostic Score (GPS) were calculated. Associations between inflammatory markers and their predictive value for OS were tested.

RESULTS

The majority of patients had elevated inflammatory markers (50-70%). Strong inter-relationships were observed between the different inflammatory indices. Only NLR and GPS were independently predictive of OS. A combined NLR and GPS score demonstrated 11 month differences in overall OS between patients with normal and elevated inflammatory status. Normalisation of NLR after three doses of chemotherapy was associated with significant improvement in survival.

CONCLUSION

This study found that NLR predicts the clinical outcomes for patients with advanced cancer treated with docetaxel. The clinical utilisation of NLR should be validated in a larger patient population to confirm its utility.