Metastatic colorectal cancer: current systemic treatment options

Metronomic chemotherapy as a potential partner of immune checkpoint inhibitors for metastatic colorectal cancer treatment

The use of immune checkpoint inhibitors (ICIs) in clinical practice for the treatment of metastatic colorectal cancer (mCRC) is currently limited to patients with deficient mismatch repair (dMMR) or high microsatellite instability (MSI-H), which comprise less than 5% of all mCRC cases. Combining ICIs with anti-angiogenic inhibitors, which modulate the tumor microenvironment, may reinforce and synergize the anti-tumor immune responses of ICIs. In mCRCs, combinations of pembrolizumab and lenvatinib have shown good efficacy in early phase trials. These results suggest the potential utility of immune modulators as partners in combination treatment with ICIs in immunologically cold microsatellite stable, as well as hot dMMR/MSI-H tumors. Unlike conventional pulsatile maximum tolerated dose chemotherapy, low-dose metronomic (LDM) chemotherapy recruits immune cells and normalizes vascular-immune crosstalk, similar to anti-angiogenic drugs. LDM chemotherapy mostly modulates the tumor stroma rather than directly killing tumor cells. Here, we review the mechanism of LDM chemotherapy in terms of immune modulation and its potential as a combination partner with ICIs for the treatment of patients with mCRC tumors, most of which are immunologically cold.

Role of Patient-Reported Outcomes in Clinical Trials in Metastatic Colorectal Cancer: A Scoping Review

PURPOSE

To perform a scoping review on the use of Patient-Reported Outcome Measures (PROMs) in randomized trials on systemic therapy in patients with metastatic colorectal cancer (mCRC) between 2010 and 2021.

METHODS

First, a search on clinicaltrials.gov was performed, looking for randomized trials in mCRC. The use of PROMs was analyzed quantitatively. Subsequently, we assessed the completeness of PROM reporting based on the CONSORT PRO extension in publications related to the selected trials acquired using Embase and PubMed.

RESULTS

A total of 46/176 trials were registered on clinicaltrials.gov used PROMs. All these trials used validated PROM instruments. The EORTC QLQ-C30 was most frequently used (37 times), followed by the EQ-5D (21 times) and the EORTC QLQ-CR29 (six times). A total of 56/176 registered trials were published. In 35% (n = 20), the results of the PROMs were available. Overall, 7/20 (35%) trials documented all items of the CONSORT PRO extension and quality of reporting according to the CONSORT PRO extension was higher than in the period 2004-2012. In 3/20 (15%) of the published trials, the results of PROMs were not discussed nor included in the positioning of the new treatment compared to the reference treatment.

CONCLUSION

When PROMs are used, the quality of reporting on patient-reported outcomes is improving, but this must continue in order to optimize the translation of trial results to individual patient values.

DDX54 Plays a Cancerous Role Through Activating P65 and AKT Signaling Pathway in Colorectal Cancer

Colorectal cancer (CRC) is one of the most malignant cancers, and its incidence is still steadily increasing. The DDX RNA helicase family members have been found to play a role in various cancers; however, the role of DDX54 in colorectal cancer is still unclear and needed to be defined. Here, we found DDX54 was overexpressed in CRC tissues by the label-free mass spectrum, which was also verified in tissue microarray of colon cancer, as well as the CRC cell lines and TCGA database. High DDX54 level was correlated with tumor stage and distant metastasis, which always indicated a poor prognosis to the CRC patients. DDX54 could promote the proliferation and mobility of CRC cells through increasing the phosphorylation level p65 and AKT leading to the tumorigenesis. Here, we have preliminarily studied the function of DDX54 in CRC, which would improve our understanding of the underlying biology of CRC and provide the new insight that could be translated into novel therapeutic approaches.

Silencing of lncRNA EZR-AS1 inhibits proliferation, invasion, and migration of colorectal cancer cells through blocking transforming growth factor β signaling

Long non-coding RNA (lncRNA) plays a key regulatory role in the pathogenesis of colorectal cancer (CRC). In the present study, the specific regulatory role of lncRNA ezrin antisense RNA 1 (EZR-AS1) on CRC was investigated. The expression of lncRNA EZR-AS1 was significantly up-regulated in CRC cell lines (HCT8, HCT116, HT29, and SW620 cells), which was significantly different from that of normal human fetal colonic mucosa cells (FHC cells) (P<0.01). HCT116 and HT29 cells were then transfected with EZR-AS1 shRNA (sh-EZR-AS1) to silence lncRNA EZR-AS1 (P<0.01). When compared with the Control, after transfection of SH-EZR-AS1, E-cadherin was up-regulated, Vimentin was down-regulated, the apoptosis rate was increased, the cell viability, wound healing rate, and the number of invasive cells were decreased in HCT116 and HT29 cells (P<0.05). Silencing of lncRNA EZR-AS also significantly reduced the tumor volume and weight in mice injected with sh-EZR-AS1-transfected HCT116 and HT29 cells (P<0.05). The regulatory relationship between lncRNA EZR-AS1 and transforming growth factor β (TGF-β) signaling was further identified in CRC cells. Silencing of lncRNA EZR-AS1 significantly down-regulated TGF-β, Smad2, and α-SMA expression in HCT116 and HT29 cells at the protein level (P<0.05). The intervention of SB431542 (a TGF-β receptor blocker) and silencing of Smad2 both significantly down-regulated lncRNA EZR-AS1 expression in HCT116 and HT29 cells (P<0.01). In conclusion, silencing of lncRNA EZR-AS1 inhibited the proliferation, invasion, migration, and epithelial–mesenchymal transition, and promoted the apoptosis of CRC cells through blocking TGF-β signaling.

Expression of factors and key components associated with the PI3K signaling pathway in colon cancer

The pathophysiology of colorectal cancer (CRC) has not been fully elucidated. The dysregulation of the phosphatidylinositol 3-kinase (PI3K) signaling pathway frequently contributes to the tumorigenesis and progression of human cancer. The aim of the present study was to explore the expression and clinical significance of a number of associated factors and key components of the PI3K signaling pathway, including phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit α (p110α), phosphorylated protein kinase B (p-Akt) Ser473, p-mammalian target of rapamycin (mTOR) Ser2448, cyclin D1, cyclin dependent kinase (CDK)4, RELA proto-oncogene, nuclear factor-κβ subunit (p65), Ras and extracellular signal-regulated kinase (ERK)1/2 in human CRC. The expression of target proteins was detected using immunohistochemistry (IHC) in 65 CRC cases and 15 colonic adenoma cases. The association between the expression of target proteins and clinical pathological parameters was analyzed using a χ² test. IHC results revealed that the expression of all target proteins was significantly increased in CRC tissues compared with in colonic adenoma tissues (P<0.05). No significant associations were observed between the expression of p110α, p-Akt Ser473, p-mTOR Ser2448 and sex, age, differentiation, lymph node metastasis or Tumor-Node-Metastasis staging (P>0.05). Cyclin D1, CDK4 and Ras were revealed to be expressed significantly higher in poorly differentiated CRC compared with moderately differentiated CRC (P<0.05). Expression of p65 and ERK1/2 were significantly increased in cancer tissues with lymph node metastasis compared with cancer tissues without lymph node metastasis (P<0.05). These results suggest that the target proteins may all participate in the tumorigenesis of CRC. Furthermore, cyclin D1, CDK4, Ras, p65 and ERK1/2 may be important in the progression of CRC. The results of the present study may provide novel predictive factors and therapeutic targets for CRC.

A phase II clinical study of combining FOLFIRI and bevacizumab plus erlotinib in 2nd-line chemotherapy for patients with metastatic colorectal cancer

We conducted an open-label single-arm phase II study by combining irinotecan (FOLFIRI) and bevacizumab (BV) plus erlotinib (ER) in 2nd-line chemotherapy for patients with metastatic colorectal cancer (mCRC).Eligible mCRC patients received 1st-line standard chemotherapy but still had progressive disease. They were given FOLFIRI plus BV at 2.5 mg/kg on day 1 per 2-week cycle, and daily 150 mg ER. The primary endpoint is progression-free survival (PFS).A total of 122 patients enrolled in the study. Among them, 55.7% were male patients and median age was 58.4 years (29-72 years). Median PFS was 7.1 months (95% CI 4.3-10.2). Median overall survival (OS) was 13.5 months (95% CI 9.7-16.4). No patients had complete responses, 24 patients had partial response (19.6%) and 59 had stable disease (48.4%). The most frequent adverse event (AE) was rash, with 66 patients (54.1%) had grade 3/4 rash. Other frequent grade 3/4 AEs were fatigue (n = 36, 29.5%), bleeding (n = 31, 25.4%), neutropenia (n = 23, 18.9%), and platelets (n = 14, 11.5%).Combining FOLFIRI and BV plus ER in 2nd-line chemotherapy is efficient to treat mCRC patients with acceptable safety.

Metronomic chemotherapy in metastatic colorectal cancer

Overall survival and quality of life of patients with metastatic colorectal cancer (mCRC) have improved due to the development of standard systemic treatment. However, many patients are still suffering from the eventual progression of cancer, treatment-related toxicities, and the economic burden of new drugs. Salvage or maintenance therapy, which consistently controls or stabilizes tumor progression without debilitating quality of life, is required. Recently, metronomic capecitabine maintenance therapy after disease control using conventional chemotherapy with maximal tolerated doses has demonstrated beneficial results in a phase III trial. Metronomic chemotherapy has been known to control tumors through antiangiogenesis and immunomodulation as well as a direct effect on tumor-initiating cells. It has the characteristics of being minimally toxic, inexpensive, and durable for maintaining disease stabilization. Therefore, patients with mCRC, who tend to be elderly and frail and have been previously treated, might be suitable for metronomic therapeutic strategies. Furthermore, antiangiogenic therapy has been an important component in treating mCRC, but the schedules and doses of metronomic chemotherapy have not yet been established. Here we review translational and clinical research on metronomic chemotherapy in colorectal cancer (CRC).

Anti-VEGFR2-interferon-α2 regulates the tumor microenvironment and exhibits potent antitumor efficacy against colorectal cancer

Interferon-α (IFNα) has multiple antitumor effects including direct antitumor toxicity and the ability to potently stimulate both innate and adaptive immunity. However, its clinical applications in the treatment of malignancies have been limited because of short half-life and serious adverse reactions when attempting to deliver therapeutically effective doses. To address these issues, we fused IFNα2a to the anti-vascular endothelial growth factor and receptor 2 (VEGFR2) antibody JZA00 with the goal of targeting it to the tumor microenvironment where it can stimulate the antitumor immune response. The fusion protein, JZA01, is effective against colorectal cancer by inhibiting angiogenesis, exhibiting direct cytotoxicity, and activating the antitumor immune response. Although JZA01 exhibited reduced IFNα2 activity in vitro compared with native IFNα2, VEGFR2 targeting permitted efficient antiproliferative, proapoptotic, antiangiogenesis, and immune-stimulating effects against the colorectal tumors HCT-116 and SW620. JZA01 showed in vivo efficacy in NOD-SCID mice-bearing established HCT-116 tumors. In conclusion, this study describes an antitumor immunotherapy that is highly promising for the treatment of colorectal cancer.

Reduced Expression of Galectin-9 Contributes to a Poor Outcome in Colon Cancer by Inhibiting NK Cell Chemotaxis Partially through the Rho/ROCK1 Signaling Pathway

Galectin-9 is a widely expressed protein that is involved in immune regulation and tumorpathogenesis and serves as a marker of a poor prognosis in various types of cancers. However, the clinical impact and the precise mechanism by which this protein contributes to colon tumor progression are unclear. In the present study, we detected the expression of galectin-9 and CD56 cells using immunohistochemistry. Spearman's rank correlation was used to clarify the association between galectin-9 expression and natural killer (NK) cell infiltration. The influence of galectin-9 on NK-92 cell migration was evaluated in vitro using transwell chemotaxis assays. The role of rh-galectin-9 in F-actin polarization in NK-92 cells was investigated using laser scanning confocal microscopy. We showed that galectin-9 was expressed in 101 (78.91%) colon tumor tissues and that was expressed at lower levels in these tissues than in para-tumor tissues. Low levels of galectin-9 expression were positively correlated with a poor histological grade and lymph node metastasis (P<0.05). A Kaplan-Meier method and Cox proportional hazards regression analysis showed that overall survival was longer in patients with high galectin-9 expression in an 8-year follow-up (P<0.05). Spearman's rank correlation indicated that there was a linear correlation between galectin-9 expression and CD56+ NK cell infiltration (R(2) = 0.658; P<0.0001). Galectin-9 stimulated migration in human NK-92 cells by affecting F-actin polarization through the Rho/ROCK1 signaling pathway. These results suggest that galectin-9 expression potentially represents a novel mechanism for tumors to escape immune surveillance in colon tumors.

Patterns of Treatment Sequences in Chemotherapy and Targeted Biologics for Metastatic Colorectal Cancer: Findings from a Large Community-Based Cohort of Elderly Patients

Background

Over the last decade, multiple chemotherapies/targeted biologics have been approved for metastatic colorectal cancer (mCRC). However, evidence is limited with regards to the array of treatments received by mCRC patients.

Objective

This study examines treatment sequences (first- to third-line chemotherapy/targeted biologics) and the factors associated with first-line targeted biologics and common treatment sequences for elderly mCRC patients treated in a community setting.

Methods

A retrospective cohort study was conducted in mCRC patients diagnosed from January 2004 through December 2009 using the Surveillance, Epidemiology and End Results Medicare-linked database. The treatment sequences administered to elderly mCRC patients were empirically identified.

Results

Of 4418 mCRC patients who received treatment, 1370 (31 %) received first, second, and third line; 1164 (26 %) received first and second line; and 1884 (43 %) received only first line. The most common first line of treatment for mCRC patients was 5-fluorouracil/leucovorin + oxaliplatin (FOLFOX) + bevacizumab (23 %) and FOLFOX (23 %). 5-fluorouracil/leucovorin + irinotecan (FOLFIRI)-based regimens were commonly (22 %) administered in second line. The most common treatment sequence was first-line oxaliplatin or irinotecan followed by second-line oxaliplatin or irinotecan + bevacizumab followed by a third-line targeted biologic. Of patients who received first-line therapy, 47 % also received a targeted biologic, and the factors associated were age, comorbidity score, cancer site, geographic location, and year of diagnosis.

Conclusion

Elderly mCRC patients receive a multitude of treatments in various sequences. Further exploration of the comparative effectiveness of treatment sequences may yield important information for improving mCRC survival.

Electronic supplementary material

The online version of this article (doi:10.1007/s40801-015-0059-9) contains supplementary material, which is available to authorized users.

KRAS status and resistance to epidermal growth factor receptor tyrosine-kinase inhibitor treatment in patients with metastatic colorectal cancer: a meta-analysis

AIM

This study reviewed the association between KRAS mutation and resistance to treatment with epidermal growth factor receptor (EGFR) tyrosine-kinase inhibitors (TKIs) in patients with metastatic colorectal cancer (mCRC).

METHOD

A search was carried out of PubMed, MEDLINE, EMBASE and the Cochrane Library databases (to November 2013) without language restrictions.

RESULTS

Ten studies were included in the final meta-analysis, consisting of 1339 patients with mCRC, of whom 427 (32%) had a KRAS mutation. The objective response rate (ORR) of mCRC patients with KRAS mutation was 8% (33/427), whereas the ORR of mCRC patients with wild-type KRAS was 34% (306/912). The overall pooled response rate (RR) for the ORR was 1.297 (95% CI 1.244-1.353, P < 0.01). Subgroup analysis comparing cetuximab monotherapy treatment with cetuximab plus chemotherapy, showed a pooled RR of 1.26 (95% CI 1.12-0.63, P < 0.01) and 1.30 (95% CI 1.25-1.36, P < 0.01), respectively. For patients receiving anti-EGFR with monoclonal antibodies (mAb) given as first-line treatment or not, the pooled RRs were 1.34 (95% CI 1.23-1.46, P < 0.01) and 1.29 (95% CI 1.23-1.35, P < 0.01). The data on progression-free survival from five studies in the meta-analysis gave a hazard ratio (HR) of 1.99 with a 95% CI of 1.69-2.29. Finally, the data for overall survival in mCRC patients were pooled from the only three studies reporting the HR (1.80; 95% CI 1.50-2.10). None of the results had any evidence of heterogeneity.

CONCLUSION

All the results favoured a stronger link between mutant KRAS and anti-EGFR mAb, but due to a mutually exclusive relationship between KRAS and other gene mutations the clinical usefulness of KRAS mutation as a selection marker for sensitivity to EGFR TKIs in mCRC is limited.

Systemic Therapy for Metastatic Colorectal Cancer: Patterns of Chemotherapy and Biologic Therapy Use in US Medical Oncology Practice

PURPOSE

With the emergence of new chemotherapies and biologic agents in the treatment of metastatic colorectal cancer (mCRC), the optimal combination and sequencing of these therapies are yet to be determined. This study examined the extent and pattern of chemotherapy and biologic therapy use by line of treatment. Biologic continuation and dose escalation were also examined.

METHODS

This study used an integrated electronic medical record database of 91 US oncology practices. Records were analyzed for 1,655 adult patients with mCRC who were treated from January 1, 2004 to January 31, 2008 with systemic therapy and could be observed for ≥ 3 months beyond their diagnosis of metastatic disease. Combination and sequence of individual drugs and regimens were examined.

RESULTS

For first-line therapy, the most common chemotherapy backbone was infused fluorouracil, leucovorin, and oxaliplatin (FOLFOX; 40.5% of patients), and the most common treatment regimen was FOLFOX plus bevacizumab (26.2%). For second-line therapy, fluorouracil, leucovorin, and irinotecan (FOLFIRI) was the most common chemotherapy backbone (25.7%), and FOLFIRI plus bevacizumab was the most common treatment regimen (18.3%). Across the study period, 68.6%, 22%, and 7% of patients received bevacizumab, cetuximab, and panitumumab, respectively. Among 412 patients receiving bevacizumab-containing regimens as first-line therapy who then received second-line therapy, 58% continued receiving bevacizumab, with dose escalation observed in 44%.

CONCLUSION

The most commonly used chemotherapy backbones for mCRC treatment were first-line FOLFOX and second-line FOLFIRI. Bevacizumab was the most frequently administered biologic therapy. Continuation and dose escalation with bevacizumab were frequently observed across lines of therapy.

Prognostic factors in primary and iterative surgery of colorectal liver metastases

The aim of this study was to evaluate the results of surgery of colorectal liver metastases and assess prognostic factors influencing the outcome. A total of 135 hepatic resections performed in 107 patients was reviewed. The following prognostic factors were analyzed: primary tumor localization, Dukes stage, number and presence of metastases in one or two lobes, synchronous or metachronous occurrence, type of resection, use and modality of chemotherapy. The perioperative morbidity rate was 6.5% and mortality was 1.9%. Overall survival was 41.2% and disease-free survival 31.5% at 5 years. Survival at 5 years was better for patients with metachronous than for those with synchronous lesions (60.9% vs 28.1%; p<0.05). There were no significant differences in terms of long-term survival between patients with synchronous metastases that were excised simultaneously or with a delay of 3-6 months (p=n.s.). Site of the primary tumor, Dukes stage, number of metastases and type of resection did not influence survival. A favorable survival trend was observed in those patients who underwent both neoadjuvant and adjuvant chemotherapy. The overall survival rate at 5 years was 45.3% for patients undergoing a second hepatic resection and 50% for those with a third or a fourth hepatic resection. Liver resection remains the "gold standard" for the treatment of patients with colorectal liver metastases, with metachronous type having a better outcome than synchronous. Simultaneous or delayed surgery for synchronous metastases does not influence prognosis. Iterative resection is very encouraging and justifies an aggressive surgical approach.

Combined treatment with bevacizumab and standard chemotherapy restores abnormal immune parameters in advanced colorectal cancer patients

BACKGROUND

Bevacizumab, a monoclonal antibody (mAb) targeting vascular endothelial growth factor (VEGF), has produced promising results when combined with chemotherapy in the treatment of advanced colorectal cancer (CRC). The aim of the present study was to define the immunological profile of metastatic CRC patients at baseline and following chemotherapy with either irinotecan/5-fluorouracil/leucovorin (IFL) alone or IFL in combination with.bevacizumab (B-IFL).

METHODS

Peripheral blood mononuclear cells (PBMCs) obtained from healthy donors (HD) (n = 20) and patients (n = 40) were tested for T-cell proliferation in the autologous mixed lymphocyte reaction (auto-MLR), and cytokine production following stimulation with anti-CD3 mAb.

RESULTS

PBMCs obtained from CRC patients prior to treatment exhibited lower auto-MLR responses and low production of IL-2, IFN-γ, IL-12 and IL-18 cytokines, whereas IL-4 and IL-10 cytokines were increased as compared to HD (p < 0.001, for all parameters) following in vitro stimulation with anti-CD3 mAb. During treatment, and in particular in week 12 of evaluation, IL-2 (p < 0.001 for both IFL and B-IFL groups), IFN-γ (p < 0.001 for IFL and p = 0.001 for B-IFL), IL-12 (p < 0.001 for both IFL and B-IFL) and IL-18 (p < 0.001 for both IFL and B-IFL) production, as well as auto-MLR responses increased (p < 0.001 for both IFL and B-IFL), whereas IL-4 (p < 0.001 for IFL and p = 0.001 for B-IFL) and IL-10 [p < 0.001 for IFL and p = 0.067 (non-significant) for B-IFL] production decreased over baseline in the two treatment groups, yet their respective values never reached those of HD. Moreover, IL-2, IFN-γ production, and auto-MLR were higher in the B-IFL over the IFL treatment group (p < 0.001, p < 0.04, p < 0.001, respectively).

CONCLUSION

Our study demonstrates that the abnormal immune parameters observed in metastatic CRC patients at presentation can substantially improve during treatment with either IFL or B-IFL. The immune parameters examined can provide a sensitive and valuable tool for monitoring immune function in CRC patients, and could be applied as surrogate markers predicting treatment-related outcome.

Outcomes of irinotecan-based chemotherapy regimens in elderly Medicare patients with metastatic colorectal cancer

BACKGROUND

Several population-based studies have confirmed the benefits of adjuvant chemotherapy with 5-fluorouracil/leucovorin for treatment of colorectal cancer. Few population-based studies have evaluated other chemotherapies that are now available for colorectal cancer management.

OBJECTIVE

This study primarily sought to evaluate the survival benefit of first-line irinotecan use in a group of Medicare patients with stage IV (metastatic) colorectal cancer.

METHODS

Data on chemotherapy users with a diagnosis of colorectal cancer reported between 1998 and 2002 were obtained from the Surveillance Epidemiology and End Results (SEER)-Medicare database. Irinotecan, marketed in 1997, was one of the newer chemotherapy agents in the available data. Chemotherapy episodes, defined as periods of continuous chemotherapy treatment with no gaps >90 days between successive claims, were identified. The first chemotherapy episode after diagnosis was used to identify lines of treatment: patients may have initiated irinotecan therapy within 2 months (first-line), used irinotecan later in the first episode (second-line), or not used irinotecan at all. Descriptive statistics were generated and a multivariable Cox proportional hazards model was used to determine the survival benefit of irinotecan. Secondary analyses explored the survival benefit in specific patient subgroups. The impact of irinotecan use on health care utilization also was assessed.

RESULTS

Of 3327 chemotherapy users (mean/median age, 75 years), 842 (25.3%) initiated chemotherapy using irinotecan. No overall survival benefit for irinotecan was observed in the primary analysis comparing irinotecan initiators with all other chemotherapy users (including those who used irinotecan subsequently). Covariates that were negatively associated with survival included older age, presence of >1 comorbidity, a high tumor grade, lymph node involvement, and a primary tumor site in the colon. Surgery was positively associated with a lower hazard of death. In subgroup analyses that excluded subsequent irinotecan users, a survival benefit for irinotecan was observed but diminished over time. Irinotecan users had higher rates of hospitalizations possibly due to chemotherapy-related adverse effects. This retrospective claims study had limitations such as a lack of information on patient performance status, dosing, and the types of regimens used; hence, certain assumptions had to be made and selection bias may have been involved.

CONCLUSIONS

The definitive survival advantage of irinotecan observed in clinical trials was not reproducible in this population of elderly Medicare patients. The results emphasize the need for expansion of trials to include a more diverse patient group as well as continued evaluation of more recent chemotherapies in real-world settings.

Clinical significance of microvessel count in patients with metastatic liver cancer originating from colorectal carcinoma

BACKGROUND

Microvessel count (MVC) has been correlated with patient prognosis in hepatocellular carcinoma. We investigated whether MVC assessed by staining with CD34 antibody was associated with disease-free and overall survival in patients with metastatic liver cancer (MLC).

METHODS

We examined relationships between MVC and clinicopathologic factors or postoperative outcomes in 139 MLC patients who underwent hepatectomy between 1990 and 2006. CD34 expression was analyzed by the immunohistochemical method.

RESULTS

MVC was associated with fibrous pseudocapsular formation on histological examination. By means of the modern Japanese classification of liver metastasis, poorer survival was associated with higher score, poorly differentiated adenocarcinoma, higher preoperative carcinoembryonic antigen (CEA) level, fibrous pseudocapsular formation, and smaller surgical margin. Shorter disease-free survival was associated with higher score when the Japanese classification of liver metastasis was used, multiple or bilobar tumor, regional lymph node metastasis in primary colon carcinoma, preoperative CEA level, fibrous pseudocapsular formation, and smaller surgical margin (<5 mm). Higher MVC (>or=406/mm(2)) was associated with decreased disease-free and overall survival by univariate analysis (P = .034 and P = .021, respectively), and higher MVC represented an independently poor prognostic factor in overall survival by Cox multivariate analysis (risk ratio, 2.71; P = .023) in addition to histological differentiation.

CONCLUSIONS

Tumor MVC seems to be a useful prognostic marker of MLC patient survival.

Predictors of survival and toxicity in patients on adjuvant therapy with 5-fluorouracil for colorectal cancer

The present study aimed at investigating whether the simultaneous evaluation of pharmacokinetic, pharmacogenetic and demographic factors could improve prediction on toxicity and survival in colorectal cancer patients treated with adjuvant 5-fluorouracil (5FU)/leucovorin therapy. One hundred and thirty consecutive, B2 and C Duke's stage colorectal cancer patients were prospectively enrolled. 5FU pharmacokinetics was evaluated at the first cycle. Thymidylate synthase (TYMS) 5′UTR and 3′UTR polymorphisms and methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms were assessed in peripheral leukocytes. Univariate and multivariate analyses were applied to evaluate which variables could predict chemotherapy-induced toxicity, disease-free survival (DFS) and overall survival (OS). Multivariate analysis showed that: (a) low 5FU clearance was an independent predictive factor for severe toxicity (OR=7.32; P<0.0001); (b) high-5FU clearance predicted poorer DFS (HR=1.96; P=0.041) and OS (HR=3.37; P=0.011); (c) advanced age was associated with shorter DFS (HR=3.34; P=0.0008) and OS (HR=2.66; P=0.024); (d) the C/C genotype of the MTHFR C677T polymorphism was protective against grade 3–4 toxicity (P=0.040); (e) none of the TYMS polymorphisms could explain 5FU toxicity or clinical outcome.

Can UGT1A1 genotyping reduce morbidity and mortality in patients with metastatic colorectal cancer treated with irinotecan? An evidence-based review

This evidence-based review addresses the question of whether testing for UGT1A1 mutations in patients with metastatic colorectal cancer treated with irinotecan leads to improvement in outcomes (e.g., irinotecan toxicity, response to treatment, morbidity, and mortality), when compared with no testing. No studies were identified that addressed this question directly. The quality of evidence on the analytic validity of current UGT1A1 genetic testing methods is adequate (scale: convincing, adequate, inadequate), with available data indicating that both analytic sensitivity and specificity for the common genotypes are high. For clinical validity, the quality of evidence is adequate for studies reporting concentration of the active form of irinotecan (SN-38), presence of severe diarrhea, and presence of severe neutropenia stratified by UGT1A1 common genotypes. The strongest association for a clinical endpoint is for severe neutropenia. Patients homozygous for the *28 allele are 3.5 times more likely to develop severe neutropenia compared with individuals with the wild genotype (risk ratio 3.51; 95% confidence interval 2.03-6.07). The proposed clinical utility of UGT1A1 genotyping would be derived from a reduction in drug-related adverse reactions (benefits) while at the same time avoiding declines in tumor response rate and increases in morbidity/mortality (harms). At least three treatment options for reducing this increased risk have been suggested: modification of the irinotecan regime (e.g., reduce initial dose), use of other drugs, and/or pretreatment with colony-stimulating factors. However, we found no prospective studies that examined these options, particularly whether a reduced dose of irinotecan results in a reduced rate of adverse drug events. This is a major gap in knowledge. Although the quality of evidence on clinical utility is inadequate, two of three reviewed studies (and one published since our initial selection of studies for review) found that individuals homozygous for the *28 allele had improved survival. Three reviewed studies found statistically significant higher tumor response rates among individuals homozygous for the *28 allele. We found little or no direct evidence to assess the benefits and harms of modifying irinotecan regimens for patients with colorectal cancer based on their UGT1A1 genotype; however, results of our preliminary modeling of prevalence, acceptance, and effectiveness indicate that reducing the dose would need to be highly effective to have benefits outweigh harms. An alternative is to increase irinotecan dose among wild-type individuals to improve tumor response with minimal increases in adverse drug events. Given the large number of colorectal cancer cases diagnosed each year, a randomized controlled trial of the effects of irinotecan dose modifications in patients with colorectal cancer based on their UGT1A1 genotype is feasible and could clarify the tradeoffs between possible reductions in severe neutropenia and improved tumor response and/or survival in patients with various UGT1A1 genotypes.

Panitumumab: in metastatic colorectal cancer with wild-type KRAS

Panitumumab is a fully human IgG2 monoclonal antibody that is highly selective for the epidermal growth factor receptor (EGFR), which is overexpressed in 25-77% of colorectal cancers and is often associated with a poor prognosis. Binding of panitumumab to EGFR reduces cell proliferation and mediator production, and induces apoptosis. In a comparative, phase III trial in adult patients with chemotherapy-refractory metastatic colorectal cancer, intravenous panitumumab 6 mg/kg every 2 weeks plus best supportive care (BSC) improved progression-free survival (PFS) [primary endpoint] and objective tumor response rate to a significantly greater extent than BSC alone. The improvement in PFS produced by panitumumab monotherapy was significantly greater in patients with non-mutated (wild-type) KRAS than in those with mutant KRAS (in whom no benefit from panitumumab was observed). Similarly, all patients experiencing a partial response had wild-type KRAS, while stable disease was achieved by more patients with wild-type KRAS than with mutant KRAS. The predictive value of mutant KRAS for a lack of clinical benefit with panitumumab monotherapy was supported by results from an open-label extension of the phase III study and a large phase II study. Although most patients treated with panitumumab experienced at least one adverse event, the incidence of severe adverse events resulting in discontinuation of treatment was relatively low. The most commonly reported treatment-related adverse events were skin-related toxicities, which reflect the mechanism of action of panitumumab.

[New perspectives in predicting response to chemotherapy in colorectal cancer]

In the last few years, major advances have been produced in knowledge of the pathogenesis of colorectal cancer, which have led to the development of new drugs for the treatment of this disease. Likewise, molecular markers have been identified that are useful in prognosis. However, decisions on adjuvant therapy in colorectal cancer continue to be based exclusively on histological stage. Distinct markers that can be detected in tumoral tissue may be useful in predicting response to antineoplastic drugs. The present article reviews the possible clinical utility of these markers and their role in decision-making in the treatment of patients with colorectal cancer.

K-Ras mutations and treatment outcome in colorectal cancer patients receiving exclusive fluoropyrimidine therapy

PURPOSE

K-Ras mutations predict resistance to anti-epidermal growth factor receptor (EGFR) monoclonal antibodies. Because combinations of anti-EGFR with 5-fluorouracil (5-FU)-based chemotherapy are promising treatments, we analyzed the effect of K-Ras mutations in patients having received exclusive 5-FU therapy.

EXPERIMENTAL DESIGN

This study was conducted on 93 stage IV colorectal cancer patients with unresectable measurable liver metastasis receiving 5-FU-leucovorin (56 men and 37 women; 77 cancer deaths). Liver metastases (n = 93) along with primary tumors (n = 48) were analyzed for K-Ras mutations (codons 12 and 13), p53 mutations (exons 4-9), p53 polymorphism (codon 72), thymidylate synthase (TS) polymorphism (28-bp repeats including G>C mutation), methylenetetrahydrofolate reductase polymorphism (677C>T, 1298A>C), thymidylate synthase (TS) activity, dihydropyrimidine dehydrogenase activity, folylpolyglutamate synthase activity, and p53 protein expression.

RESULTS

Thirty-six of 93 (38.7%) metastases were K-Ras mutated (30 at codon 12 and 6 at codon 13). Mutated primary tumors (16 of 48) matched perfectly with mutated metastases. The additional analyzed tumor markers were not different between K-Ras mutated and wild-type tumors. The objective response rate was 37%: 44.4% in K-Ras mutated versus 32.1% in wild-type K-Ras metastasis (P = 0.27). Low TS activity in metastasis was the only significant predictor of tumor response (P = 0.047). K-Ras status did not influence specific survival.

CONCLUSIONS

The present data indicate a perfect concordance of K-Ras mutations between primary and liver metastasis and suggest that any predictive and/or prognostic value of K-Ras mutations in treatments combining anti-EGFR monoclonal antibodies with 5-FU should be exclusively linked to the anti-EGFR agent.

Bevacizumab: a review of its use in metastatic colorectal cancer

Bevacizumab (Avastin) is a recombinant, humanized monoclonal antibody against vascular endothelial growth factor (VEGF) that is used to inhibit VEGF function in vascular endothelial cells and thereby inhibit tumour angiogenesis, upon which solid tumours depend for growth and metastasis. The addition of bevacizumab to fluoropyrimidine-based chemotherapy, with or without irinotecan or oxaliplatin, in both the first- and second-line treatment of metastatic colorectal cancer, significantly increased median progression-free survival or time to disease progression in most randomized controlled trials. Bevacizumab was generally, but not always, associated with a survival advantage; in phase III trials, the increases in median overall survival attributable to bevacizumab were 4.7 months with first-line therapy and 2.1 months with second-line therapy. In some studies, patients experienced clinical improvement without an apparent overall survival benefit. Bevacizumab had acceptable tolerability, with the majority of adverse events being generally mild and clinically manageable. However, from the UK National Health Service perspective, bevacizumab was not considered to be cost effective in combination with bolus fluorouracil/folinic acid or irinotecan/bolus fluorouracil/folinic acid. Additional pharmacoeconomic analyses from different perspectives and using clinical data for combinations with the more efficacious infusional fluorouracil/folinic acid plus oxaliplatin or irinotecan chemotherapy regimens are required. Although cost effectiveness may be a concern, the combination of bevacizumab and fluoropyrimidine-based chemotherapy has potential in the treatment of metastatic colorectal cancer.