Targeted therapies in colorectal cancer: surgical considerations

Colorectal cancer (CRC) is a leading worldwide health concern that is responsible for thousands of deaths each year. The primary source of mortality for patients with CRC is the development and subsequent progression of metastatic disease. The most common site for distant metastatic disease is the liver. Although patients with metastatic disease to the liver have several effective treatment options, the only one for cure remains surgical resection of the liver metastases. Historically, most patients with liver metastases have had unresectable disease, and only a small percentage of patients have undergone complete curative resection. However, improved systemic therapies have led to an evolution in strategies to treat metastatic CRC to the liver. Under most conditions the management of these patients remains complex; and as chemotherapy options and new targeted therapies continue to improve outcomes, it is clear that a multidisciplinary approach must be the foundation on which advanced surgical and medical techniques are employed. Here, in this review, we highlight the role of targeted therapies in the surgical management of patients with metastatic CRC to the liver.

The status of targeted agents in the setting of neoadjuvant radiation therapy in locally advanced rectal cancers

Radiotherapy has a longstanding and well-defined role in the treatment of resectable rectal cancer to reduce the historically high risk of local recurrence. In more advanced borderline or unresectable cases, where the circumferential resection margin (CRM) is breached or threatened according to magnetic resonance imaging (MRI), despite optimized local multimodality treatment and the gains achieved by modern high quality total mesorectal excision (TME), at least half the patients fail to achieve sufficient downstaging with current schedules. Many do not achieve an R0 resection. In less locally advanced cases, even if local control is achieved, this confers only a small impact on distant metastases and a significant proportion of patients (30-40%) still subsequently develop metastatic disease. In fact, distant metastases have now become the predominant cause of failure in rectal cancer. Therefore, increasing the intensity and efficacy of chemotherapy and chemoradiotherapy by integrating additional cytotoxics and biologically targetted agents seems an appealing strategy to explore-with the aim of enhancing curative resection rates and improving distant control and survival. However, to date, we lack validated biomarkers for these biological agents apart from wild-type KRAS. For cetuximab, the appearance of an acneiform rash is associated with response, but low levels of magnesium appear more controversial. There are no molecular biomarkers for bevacizumab. Although some less invasive clinical markers have been proposed for bevacizumab, such as circulating endothelial cells (CECS), circulating levels of VEGF and the development of overt hypertension, these biomarkers have not been validated and are observed to emerge only after a trial of the agent. We also lack a simple method of ongoing monitoring of 'on target' effects of these biological agents, which could determine and pre-empt the development of resistance, prior to radiological and clinical assessessments or even molecular imaging. These shortcomings probably explain our current relative lack of success in the arena of combining these agents with chemoradiation.

Current Options for the Diagnosis, Staging and Therapeutic Management of Colorectal Cancer

BACKGROUND

Colorectal cancer (CRC) is the one of the most common malignancies and is a leading cause of cancer death worldwide. The incidence of mortality from CRC has decreased in Western countries because of earlier diagnosis and improved treatment modalities; however, mortality is still increasing in most other regions of the world.

SUMMARY

Progress in the development of imaging modalities has enabled more accurate staging based on the TNM classification. The therapeutic management of CRC should involve a multi-modal approach, including high-quality surgery and an optimal choice of chemotherapy and radiotherapy regimens according to disease characteristics and patient preferences. Even in the case of metastatic disease, the optimal multi-modal treatments could achieve potential cure or long-term survival benefit in some patients. The aim of this review is to present current options regarding the diagnosis, staging and treatment management for CRC based on published research reports and the current management guidelines.

Pattern of clinically relevant mutations in consecutive series of Russian colorectal cancer patients

One hundred and ninety-five consecutive surgically treated Russian colorectal cancer (CRC) patients were retrospectively analyzed for the presence of mutations in KRAS, NRAS, BRAF and PIK3CA genes as well as for the microsatellite instability status. Comparison between high-resolution melting analysis, co-amplification at lower denaturation temperature PCR, DNA sequencing and allele-specific PCR for the detection of KRAS codon 12/13 mutations revealed that none of these methods alone provided satisfactory results in 100 % of the analyzed cases; this experience supports the use of more than one mutation-detecting technique at least in some circumstances. KRAS codon 12/13 substitutions were detected in 70 (35.9 %) CRC cases. Other mutations in the RAS/RAF genes occurred in 22 (11.3 %) cases and included rare KRAS (n = 6), NRAS (n = 8) and BRAF (n = 8) alterations. 5 BRAF mutations affected codon 600, while the remaining 3 potentially functional substitutions were located in the position 594. Twenty-four (12.3 %) CRC cases carried mutations in the PIK3CA, and 18 of these tumors also contained activating alteration in the RAS/RAF genes (p = 0.007). Only 3 (1.5 %) CRC cases showed high-level microsatellite instability (MSI-H) as determined by a panel of mononucleotide markers. Overall, the distribution of potentially predictive mutations in Russian CRC cases is similar to the one observed in other patient series of European descent. Noticeable occurrence of D594G mutation in BRAF oncogene and low frequency of MSI-H may deserve specific attention.

Consensus statement on the multidisciplinary management of patients with recurrent and primary rectal cancer beyond total mesorectal excision planes

BACKGROUND

The management of primary rectal cancer beyond total mesorectal excision planes (PRC-bTME) and recurrent rectal cancer (RRC) is challenging. There is global variation in standards and no guidelines exist. To achieve cure most patients require extended, multivisceral, exenterative surgery, beyond conventional total mesorectal excision planes. The aim of the Beyond TME Group was to achieve consensus on the definitions and principles of management, and to identify areas of research priority.

METHODS

Delphi methodology was used to achieve consensus. The Group consisted of invited experts from surgery, radiology, oncology and pathology. The process included two international dedicated discussion conferences, formal feedback, three rounds of editing and two rounds of anonymized web-based voting. Consensus was achieved with more than 80 per cent agreement; less than 80 per cent agreement indicated low consensus. During conferences held in September 2011 and March 2012, open discussion took place on areas in which there is a low level of consensus.

RESULTS

The final consensus document included 51 voted statements, making recommendations on ten key areas of PRC-bTME and RRC. Consensus agreement was achieved on the recommendations of 49 statements, with 34 achieving consensus in over 95 per cent. The lowest level of consensus obtained was 76 per cent. There was clear identification of the need for referral to a specialist multidisciplinary team for diagnosis, assessment and further management.

CONCLUSION

The consensus process has provided guidance for the management of patients with PRC-bTME or RRC, taking into account global variations in surgical techniques and technology. It has further identified areas of research priority.

454 next generation-sequencing outperforms allele-specific PCR, Sanger sequencing, and pyrosequencing for routine KRAS mutation analysis of formalin-fixed, paraffin-embedded samples

Detection of KRAS mutations in archival pathology samples is critical for therapeutic appropriateness of anti-EGFR monoclonal antibodies in colorectal cancer. We compared the sensitivity, specificity, and accuracy of Sanger sequencing, ARMS-Scorpion (TheraScreen®) real-time polymerase chain reaction (PCR), pyrosequencing, chip array hybridization, and 454 next-generation sequencing to assess KRAS codon 12 and 13 mutations in 60 nonconsecutive selected cases of colorectal cancer. Twenty of the 60 cases were detected as wild-type KRAS by all methods with 100% specificity. Among the 40 mutated cases, 13 were discrepant with at least one method. The sensitivity was 85%, 90%, 93%, and 92%, and the accuracy was 90%, 93%, 95%, and 95% for Sanger sequencing, TheraScreen real-time PCR, pyrosequencing, and chip array hybridization, respectively. The main limitation of Sanger sequencing was its low analytical sensitivity, whereas TheraScreen real-time PCR, pyrosequencing, and chip array hybridization showed higher sensitivity but suffered from the limitations of predesigned assays. Concordance between the methods was k = 0.79 for Sanger sequencing and k > 0.85 for the other techniques. Tumor cell enrichment correlated significantly with the abundance of KRAS-mutated deoxyribonucleic acid (DNA), evaluated as ΔCt for TheraScreen real-time PCR (P = 0.03), percentage of mutation for pyrosequencing (P = 0.001), ratio for chip array hybridization (P = 0.003), and percentage of mutation for 454 next-generation sequencing (P = 0.004). Also, 454 next-generation sequencing showed the best cross correlation for quantification of mutation abundance compared with all the other methods (P < 0.001). Our comparison showed the superiority of next-generation sequencing over the other techniques in terms of sensitivity and specificity. Next-generation sequencing will replace Sanger sequencing as the reference technique for diagnostic detection of KRAS mutation in archival tumor tissues.

Predictive and prognostic roles of BRAF mutation in patients with metastatic colorectal cancer treated with anti-epidermal growth factor receptor monoclonal antibodies: a meta-analysis

OBJECTIVE

This study aimed to evaluate the predictive and prognostic roles of BRAF mutation in patients with metastatic colorectal cancer (mCRC) treated with anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (MoAbs).

METHODS

Computer searches of the literature on BRAF mutation in mCRC patients were performed. Studies with objective response rate (ORR) to anti-EGFR MoAbs and/or overall survival (OS) and progression-free survival (PFS) with different BRAF gene expression in mCRC patients were eligible.

RESULTS

A total of 19 studies including 2875 patients was enrolled in the meta-analysis. BRAF mutation was detected in 246 patients. The ORR was 18.4% (40/217) in mutant BRAF group and 41.7% (831/1993) in the wild-type BRAF group. The overall risk ratio (RR) for the ORR of BRAF mutation patients compared with wild-type BRAF patients was 0.58 (95% confidence intervals [CI] 0.35-0.94, P = 0.027). The median PFS of patients with BRAF mutation was significantly shorter than that of patients with wild-type BRAF (hazard ratio [HR] 2.98, 95% CI 2.07-4.27, P < 0.001) and the median OS of patients with BRAF mutation was also significantly shorter than that of those with wild-type BRAF (HR 2.85, 95% CI 2.31-3.52, P < 0.001).

CONCLUSION

BRAF mutation is associated with poor response to anti-EGFR MoAbs and it is an adverse prognostic biomarker of the survival of patients with mCRC.

Mutation-specific antibody detects mutant BRAFV600E protein expression in human colon carcinomas

BACKGROUND

A point mutation (V600E) in the BRAF oncogene is a prognostic biomarker and may predict for nonresponse to anti-EGFR antibody therapy in patients with colorectal carcinoma. BRAFV600E mutations are frequently detected in tumors with microsatellite instability and indicate a sporadic origin. We used a mutation-specific antibody to examine mutant BRAFV600E protein expression and its concordance with BRAFV600E mutation data.

METHODS

Primary stage III colon carcinomas were analyzed for BRAFV600E mutations in exon 15, and 50 BRAFV600E mutation carriers and 25 wild-type tumors were selected for analysis of BRAF proteins by immunohistochemistry (IHC). IHC was performed in archival tissue specimens using a pan-BRAF antibody and a mutation-specific antibody against BRAFV600E proteins. Staining was scored by 2 pathologists who were blinded to clinical and mutation data.

RESULTS

Using a pan-BRAF antibody, total BRAF protein expression was observed in the tumor cell cytoplasm in 74 of 75 colon carcinomas. A mutation-specific antibody identified diffuse cytoplasmic staining of mutant BRAFV600E proteins in 49 of 74 cancers. Analysis using a polymerase chain reaction-based assay revealed that all 49 of these cancers carried BRAFV600E mutations. In contrast, BRAFV600E staining was absent in all 25 tumors that carried wild-type copies of BRAF.

CONCLUSIONS

A BRAF mutation-specific (V600E) antibody detected tumors with BRAFV600E mutations and exhibited complete concordance with a DNA-based method. These results support the use of IHC as a simplified strategy to screen colorectal cancers for BRAFV600E mutations in clinical practice.

Which is false: oxaliplatin or fluoropyrimidine? An analysis of patients with KRAS wild-type metastatic colorectal cancer treated with first-line epidermal growth factor receptor monoclonal antibody

This meta-analysis was performed to determine whether the addition of monoclonal antibodies (mAbs) of epidermal growth factor receptor (EGFR) to oxaliplatin-based chemotherapy treatment improves efficacy in KRAS wild-type metastatic colorectal cancer (mCRC), and whether infusional 5-fluorouracil (5-FU) and oxaliplatin is a preferred combination for EGFR mAbs. Oxaliplatin (including treatment), EGFR mAbs, first-line treatment, KRAS wild-type, and mCRC were used as key words. The PRIME, OPUS, COIN, and NORDIC VII trials were identified by two independent authors. Time-to-event outcomes of overall survival (OS) and progression-free survival (PFS) were analyzed using HRs (hazard ratios) with fixed effect, and response rate (RR) using odd ratios (OR) with fixed effect. A total of 1767 patients who were KRAS wild-type were included in this meta-analysis, with 866 patients in the mAbs and chemotherapy combination group and 901 patients in the chemotherapy alone group. The addition of mAbs to oxaliplatin-based chemotherapy in patients with KRAS wild-type mCRC as first-line treatment resulted in significant improvements in PFS (HR = 0.88; 95% confidence interval (CI), 0.79-0.99; P = 0.03) and response rate (RR) (OR = 1.38; 95% CI, 1.14-1.66; P = 0.009) compared with chemotherapy alone, but the difference in OS was not significant (HR = 0.96; 95% CI, 0.85-1.08; P = 0.48). However, the differences in OS and PFS were not significant when mAbs were added to bolus 5-FU or capecitabine-based regimens compared with chemotherapy alone, whereas PFS improved with an infusional 5-FU and oxaliplatin combination (P = 0.06; PFS, HR = 0.76; 95% CI, 0.65-0.86; P = 0.0002), and even OS was marginally significant, which was consistent with the subgroup analysis of cetuximab and panitumumab. EGFR mAbs combined with oxaliplatin and an infusional 5-FU regimen was associated with significantly improved RR, PFS and OS as first-line treatment in KRAS wild-type mCRC.

Multicenter phase II trial to investigate safety and efficacy of gemcitabine combined with cetuximab as adjuvant therapy in pancreatic cancer (ATIP)

BACKGROUND

To investigate whether addition of cetuximab to standard adjuvant chemotherapy with gemcitabine improves outcome in pancreatic cancer, specifically whether the rate of disease-free survival (DFS) at 18 months (primary end point) exceeds the previously reported 35% of gemcitabine alone.

PATIENTS AND METHODS

Prospective, open-label, multicenter, nonrandomized phase II study in 76 patients with R0- or R1-resected ductal adenocarcinoma of the pancreas included between October 2006 and November 2008. Gemcitabine and cetuximab were administered for 24 weeks. Secondary end points included overall survival (OS) and toxic effect.

RESULTS

Seventy-three patients received cetuximab. Median DFS was 10.0 [95% confidence interval (CI) 8.9-13.6] months and the DFS rate at month 18 of 27.1% (16.7%-37.6%) was inferior to 35%. Median OS was 22.4 (18.2-27.9) months. Subgroup analyses revealed a nonsignificant increase in DFS for patients with versus without skin toxic effect ≥ grade 2 (median 14.7 versus 8.3 months, P = 0.073) and wild-type versus mutated K-Ras (median 11.5 versus 9.3 months, P = 0.57). Grade 3/4 toxic effects included neutropenia (11.0%), thrombopenia (7%), skin toxic effect (7%) and allergic reactions (7%).

CONCLUSION

Addition of cetuximab to adjuvant gemcitabine does not seem to improve DFS or OS of unstratified pancreatic cancer patients. Trends for improved DFS in patients with wild-type K-Ras and skin toxic effect remain to be confirmed.

Shedding of c-Met ectodomain correlates with c-Met expression in non-small cell lung cancer

OBJECTIVE

The aim of this study is to reveal the correlation of shedding and expression of c-Met in non-small cell lung cancer (NSCLC) patient.

MATERIALS AND METHODS

We measured soluble c-Met and c-Met level in a panel of pre-clinical models and 197 advanced Chinese NSCLC patients by enzyme-linked immunosorbent assay and immunohistochemistry, respectively.

RESULTS

Shedding of soluble c-Met associates with total c-Met amount in pre-clinical models, and soluble c-Met correlates with both c-Met expression level and tumor size in human, high soluble c-Met predicts poorer outcome.

What is the optimal neo-adjuvant treatment for liver metastasis?

Colorectal cancer is the third most common cancer in the Western population and has a 5-year overall survival of 5-10% when metastatic. Approximately 30% of the patients with metastatic colorectal cancer have limited disease apparently isolated to the liver and, if this can be resected, the 5-year overall survival is improved to 30-60%. Therefore, it is important to identify patients who have both resectable disease and those with initially unresectable tumors who can potentially be downsized with chemotherapy to allow resection. First-line doublet chemotherapy regimens lead to response rates of 50-60%, triplet chemotherapy regimens may result in a response rate of up to 70%, and biological agents may add to responses or induce morphologic changes that facilitate disease resection. Surgical advances in recent years have also increased resectability rates and have challenged prior rules of resectability. Local therapies including ablation and radiation, often performed in conjunction with resection, may further aid in control of disease. The aim of this article is to focus on the role of neoadjuvant therapy in the treatment of colorectal liver metastases.

Bevacizumab plus chemotherapy continued beyond first progression in patients with metastatic colorectal cancer previously treated with bevacizumab plus chemotherapy: ML18147 study KRAS subgroup findings

BACKGROUND

ML18147 evaluated continued bevacizumab with second-line chemotherapy for patients with metastatic colorectal cancer (mCRC) progressing after the standard first-line bevacizumab-containing therapy.

PATIENTS AND METHODS

Evaluating outcomes according to tumor Kirsten rat sarcoma virus oncogene (KRAS) status was an exploratory analysis. KRAS data were collected from local laboratories (using their established methods) and/or from a central laboratory (mutation-specific Scorpion amplification-refractory mutation system). No adjustment was made for multiplicity; analyses were not powered to detect statistically significant differences.

RESULTS

Of 820 patients, 616 (75%) had unambiguous KRAS data; 316 (51%) had KRAS wild-type tumors and 300 (49%) had mutant KRAS tumors. The median progression-free survival (PFS) was 6.4 months for bevacizumab plus chemotherapy and 4.5 months for chemotherapy [P < 0.0001; HR = 0.61; 95% confidence interval (CI): 0.49-0.77] for wild-type KRAS and 5.5 and 4.1 months, respectively (P = 0.0027; HR = 0.70; 95% CI: 0.56-0.89) for mutant KRAS. The median overall survival (OS) was 15.4 and 11.1 months, respectively (P = 0.0052; HR = 0.69; 95% CI: 0.53-0.90) for wild-type KRAS and 10.4 versus 10.0 months, respectively (P = 0.4969; HR = 0.92; 95% CI: 0.71-1.18) for mutant KRAS. In both analyses, no treatment interaction by KRAS status was observed (PFS, P = 0.4436; OS, P = 0.1266).

CONCLUSIONS

Bevacizumab beyond first progression represents an option for patients with mCRC treated with bevacizumab plus standard first-line chemotherapy, independent of KRAS status.

Molecular diagnostics and personalized medicine in oncology: challenges and opportunities

Increasing evidence demonstrates that target-based agents are active only in molecularly selected populations of patients. Therefore, the identification of predictive biomarkers has become mandatory to improve the clinical development of these novel drugs. Mutations of the epidermal growth factor receptor (EGFR) or rearrangements of the ALK gene in non-small-cell lung cancer, and BRAF mutations in melanoma are clear examples of driver mutations and predictive biomarkers of response to treatment with specific inhibitors. Predictive biomarkers might also identify subgroups of patients that are not likely to respond to specific drugs, as shown for KRAS mutations and anti-EGFR monoclonal antibodies in colorectal carcinoma. The discovery of novel driver molecular alterations and the availability of drugs capable to selectively block such oncogenic mechanisms are leading to a rapid increase in the number of putative biomarkers that need to be assessed in each single patient. In this respect, two different approaches are being developed to introduce a comprehensive molecular characterization in clinical practice: high throughput genotyping platforms, which allow the detection of recognized genetic aberrations in clinical samples, and next generation sequencing that can provide information on all the different types of cancer-causing alterations. The introduction of these techniques in clinical practice will increase the possibility to identify molecular targets in each individual patient, and will also allow to follow the molecular evolution of the disease during the treatment. By using these approaches, the development of personalized medicine for patients with cancer will finally become possible.

Selecting patients with locally advanced rectal cancer for neoadjuvant treatment strategies

Rectal cancer remains a significant problem worldwide. Outcomes vary significantly according to the stage of disease and prognostic factors, including the distance of the tumor from the circumferential resection margin. Accurate staging, including high-resolution magnetic resonance imaging, allows stratification of patients into low-, moderate-, and high-risk disease; this information can be used to inform multidisciplinary team decisions regarding the role of neoadjuvant therapy. Both neoadjuvant short-course radiotherapy and long-course chemoradiation reduce the risk of local recurrence compared with surgery alone, but they have little impact on survival. Although there remains a need to reduce overtreatment of those patients at moderate risk, evaluation of intensified regimens for those with high-risk disease is still required to reduce distant failure rates and improve survival in these patients with an otherwise poor prognosis.

Metastatic colorectal cancer-prolonging overall survival with targeted therapies

This review provides an updated overview of the management of metastatic colorectal cancer (CRC). With widespread application of personalized therapy based on specific patient and tumor characteristics, this will enable the oncologists to optimize overall survival while maintaining quality of life. The role of k-ras and braf testing in helping select systemic therapy that includes cetuximab or bevacizumab is clarified. Current management of metastatic CRC is based on careful attention to these finer points, explained in this article.

FOLFOX4 plus cetuximab administered weekly or every second week in the first-line treatment of patients with KRAS wild-type metastatic colorectal cancer: a randomized phase II CECOG study

BACKGROUND

This randomized phase II study investigated first-line chemotherapy plus cetuximab administered every second week in KRAS wild-type metastatic colorectal cancer.

PATIENTS AND METHODS

Patients received FOLFOX4 plus either standard weekly cetuximab (arm 1) or cetuximab (500 mg/m(2)) every second week (arm 2), until disease progression or unacceptable toxicity. Primary end point was the objective response rate (ORR). Progression-free survival (PFS), overall survival (OS), disease control rate (DCR) and safety were also investigated. The study was not powered to establish non-inferiority, but aimed at the estimation of treatment differences.

RESULTS

Of 152 randomized eligible patients, 75 were treated in arm 1 and 77 in arm 2; ORRs [53% versus 62%, odds ratio 1.40, 95% confidence interval (CI) 0.74-2.66], PFS [median 9.5 versus 9.2 months, hazard ratio (HR) 0.92, 95% CI 0.63-1.34], OS (median 25.8 versus 23.0 months, HR 0.86, 95% CI 0.56-1.30) and DCR (87%) were comparable. HRs adjusted for baseline factors were 1.01 and 0.99 for PFS and OS, respectively. Frequencies of grade 3/4 adverse events in arms 1 versus 2 were similar: most common were neutropenia (28% versus 34%) and rash (15% versus 17%).

CONCLUSIONS

Activity and safety of FOLFOX4 plus either cetuximab administered weekly or every second week were similar.

A multiplex technology platform for the rapid analysis of clinically actionable genetic alterations and validation for BRAF p.V600E detection in 1549 cytologic and histologic specimens

CONTEXT

Current clinicopathologic assessment of malignant neoplastic diseases entails the analysis of specific genetic alterations that provide diagnostic, prognostic, or therapy-determining information.

OBJECTIVE

To develop and validate a robust molecular method to detect clinically relevant mutations in various tissue types and anatomic pathology specimens.

DESIGN

Genes of interest were amplified by multiplex polymerase chain reaction and sequence variants identified by liquid bead array cytometry. The BRAF assay was fully characterized by using plasmids and genomic DNA extracted from cell lines, metastatic colorectal cancer formalin-fixed, paraffin-embedded (FFPE) tissues, and thyroid nodule fine-needle aspirates.

RESULTS

Qualitative multiplex assays for 22 different mutations in the BRAF, HRAS, KRAS, NRAS, or EGFR genes were established. The high signal-to-noise ratio of the technology enabled reproducible detection of BRAF c.1799T>A (p.V600E) at 0.5% mutant allele in 20 ng of genomic DNA. Precision studies with multiple operators and instruments showed very high repeatability and reproducibility with 100% (98.7%-100%) qualitative agreement among 292 individual measures in 38 runs. Evaluation of 1549 representative pathologic specimens in 2 laboratories relative to independent reference methods resulted in 99.0% (97.6%-99.6%) agreement for colorectal FFPE tissues (n = 416) and 98.9% (98.2%-99.4%) for thyroid fine-needle aspiration specimens (n = 1133) with an overall diagnostic odds ratio of 10 856 (2451-48 078).

CONCLUSIONS

The multiplex assay system is a sensitive and reliable method to detect BRAF c.1799T>A mutation in colorectal and thyroid lesions. This optimized technology platform is suitable for the rapid analysis of clinically actionable genetic alterations in cytologic and histologic specimens.

Chemotherapy induced hepatotoxicity in metastatic colorectal cancer: a review of mechanisms and outcomes

Colorectal cancer remains one of the most common cancers worldwide. The treatment of metastatic disease has advanced considerably in the past 10 years both in terms of surgical technique and development of novel chemotherapeutic agents. The widespread use of multiple chemotherapeutic agents has lead to recognition of distinct patterns of hepatotoxicity associated with specific drugs. These side-effects have potential implications for both the patient and medical professional, but the underlying mechanisms involved in these conditions remains poorly understood. This review explores the mechanisms of action of the commonly used chemotherapeutic agents and the potential mechanisms for their hepatotoxicity. It is important that all medical professionals involved in the management of metastatic colorectal cancer understand the problems of hepatotoxicity and the impact they have on the patient.

Microwave ablation with or without resection for colorectal liver metastases

BACKGROUND

Ablation with or without resection for colorectal liver metastases has been suggested as a potential method of improving survival if complete surgical resection is not possible. This study assessed the safety and efficacy of surgical microwave ablation (MWA) with or without resection for colorectal liver metastases.

METHODS

A retrospective case series was reviewed. Data was extracted for all patients treated with open MWA with or without resection for colorectal liver metastases. Endpoints included postoperative 30-day morbidity and mortality, local treatment failure, disease free survival and overall survival.

RESULTS

A total of 43 patients with technically irresectable disease were treated with MWA; 28 underwent combined MWA and resection, whilst 15 underwent MWA as the sole treatment modality. Overall post-operative morbidity was 35%, 30-day postoperative mortality 2%. At a median follow-up of 15 months, local treatment failure was observed in 4% of ablated lesions. 3-year OS was 36% for MWA group, compared to 45% for the combined ablate/resect group with 3-year DFS of 32% and 8% respectively.

CONCLUSION

Microwave ablation with or without resection is a safe and effective method of achieving local disease control. Ablation with or without resection is associated with good long-term outcomes, and may be a suitable treatment option for small non-resectable colorectal liver metastases.

Immunohistochemistry using the BRAF V600E mutation-specific monoclonal antibody VE1 is not a useful surrogate for genotyping in colorectal adenocarcinoma

AIMS

The presence of a BRAF mutation is a strong marker for poor prognosis of colorectal carcinoma (CRC), and can be used as evidence of a sporadic mechanism of mismatch repair deficiency. BRAF mutation may also predict resistance to EGFR-targeted therapy. A BRAF V600E-specific antibody has recently become commercially available. The aim of this study was to determine whether immunohistochemistry can predict BRAF mutations in CRC.

METHODS AND RESULTS

Immunohistochemistry was performed on 52 genotyped CRC cases (17 BRAF mutant, 18 KRAS mutant, 17 BRAF/KRAS wild-type) with monoclonal antibody VE1. Cytoplasmic staining was observed in 71% of BRAF V600E mutant tumours (moderate or strong staining in 50% of these cases). Weak cytoplasmic staining was observed in 17% of KRAS mutant tumours and 35% of wild-type tumours. Non-specific nuclear staining was common. The sensitivity and specificity of immunohistochemistry with VE1 for BRAF mutation were 71% and 74%, respectively; when only moderate or strong staining was considered to be positive, the specificity was 100%, but the sensitivity only 35%.

CONCLUSIONS

Immunohistochemistry with VE1 is not a useful surrogate for genotyping in CRC. Although moderate or strong cytoplasmic staining is specific for BRAF V600E mutations, this antibody is insufficiently sensitive to serve as an effective screening tool.

The prognostic role of BRAF mutation in metastatic colorectal cancer receiving anti-EGFR monoclonal antibodies: a meta-analysis

BACKGROUND

BRAF mutation has been investigated as a prognostic factor in metastatic colorectal cancer (mCRC) undergoing anti-EGFR monoclonal antibodies (moAbs), but current results are still inconclusive. The aim of this meta-analysis was to evaluate the relationship between BRAF mutation status and the prognosis of mCRC patients treated with moAbs.

METHODS

Eligible studies were identified by systematically searching Pubmed, the Cochrane Library, Web of Knowledge, and OVID. Risk ratio (RR) for overall response rate (ORR), Hazard ratios (HRs) for Progression free survival (PFS) and Overall survival (OS) were extracted or calculated. Prespecified subgroup analyses were conducted in KRAS wild-type and in different study types. The source of between-trial variation was explored by sensitivity analyses. Quality assessment was conducted by the Hayden's criteria.

RESULTS

A total of twenty one trials including 5229 patients were identified for the meta-analysis. 343 patients displayed BRAF mutations of 4616 (7.4%) patients with known BRAF status. Patients with BRAF wild-type (WT) showed decreased risks of progression and death with an improved PFS(HR 0.38, 95% confidence intervals 0.29-0.51) and an improved OS (HR 0.35 [0.29-0.42]), compared to BRAF mutant. In KRAS WT population, there were even larger PFS benefit (HR 0.29[0.19,0.43]) and larger OS benefit (HR 0.26 [0.20,0.35]) in BRAF WT. A response benefit for BRAF WT was observed (RR 0.31[0.18,0.53]) in KRAS WT patients, but not observed in unselected patients (RR 0.76 [0.43-1.33]). The results were consistent in the subgroup analysis of different study types. Heterogeneity between trials decreased in the subgroup and explained by sensitivity analysis. No publication bias of ORR, PFS and OS were detected.

CONCLUSIONS

The results indicate that BRAF mutant is a predictive biomarker for poor prognosis in mCRC patients undergoing anti-EGFR MoAbs therapy, especially in KRAS WT patients. Additional large prospective trials are required to confirm the predictive role of BRAF status.

FOLFIRI-bevacizumab as first-line chemotherapy in 3500 patients with advanced colorectal cancer: a pooled analysis of 29 published trials

Irinotecan and infusional bolus 5-fluorouracil (5-FU)-based chemotherapy (FOLFIRI [5-fluorouracil, folinic acid, irinotecan]) + bevacizumab (FOLFIRI-B) is 1 of the cornerstones of first-line treatment of advanced colorectal cancer (CRC). However, bevacizumab was approved for use after the AVF2107 trial that included a bolus 5-FU schedule (IFL [irinotecan + 5-FU + leucovorin]). No randomized trials have been published comparing FOLFIRI and FOLFIRI-B. The aim of this review is to pool all published data on the activity and efficacy of FOLFIRI-B as first-line therapy in treating advanced CRC in prospective and retrospective studies. We performed a systematic review, through PubMed and EMBASE, of all prospective and retrospective published studies exploring the efficacy of FOLFIRI-B as first-line chemotherapy in patients with advanced CRC. Pooled estimates of the response rate (RR) and weighted median of progression-free survival (PFS) and overall survival (OS) from all FOLFIRI-B-related studies were calculated. Rates of metastasectomy and bevacizumab-related severe toxicities were reported. A total of 29 studies (8 randomized controlled trials, 1 phase IV trial, 2 phase II trials, 4 observational studies, 4 prospective nonrandomized cohort studies, and 10 retrospective case series) were retrieved for a total of 3502 patients. Overall, the pooled RR (n = 22 publications) was 51.4%. Median PFS and OS (n = 25 and 20 publications) were 10.8 months (95% confidence interval [CI], 8.9-12.8) and 23.7 months (95% CI, 18.1-31.6), respectively. The pooled rate of surgical resection of metastases (any site of surgery: n = 7 publications) was 9.3% (range, 3.6%-24%), and rate of liver resections (liver surgery only: n = 7 publications) was 18% (range 8%-25%). Grade 3-4 bevacizumab-related toxicities were also comparable with larger phase III trials. FOLFIRI-B is used worldwide as upfront treatment for stage IV CRC. This indication is confirmed by robust data about RR, PFS, and survival obtained, which this pooled analysis of 29 trials also found. FOLFIRI-B remains 1 of the referent combinations when bevacizumab is considered as first-line therapy.

Controversies in antiepidermal growth factor receptor therapy in metastatic colorectal cancer

The randomized first-line trials, including the CRYSTAL trial, the OPUS trial, and the PRIME trial, have demonstrated the significant efficacy of cetuximab or panitumumab in patients with v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) wild-type tumors. The addition of an antiepidermal growth factor receptor (anti-EGFR)-directed monoclonal antibody to chemotherapy for these patients significantly improved progression-free survival, response rates, and R0 resection rates to a greater extent than overall survival compared with patients who received chemotherapy alone. However, 2 recent randomized phase 3 trials, the MRC COIN trial and the Nordic VII trial, reported an unexpected lack of benefit from the addition of cetuximab to chemotherapy in the first-line setting. In addition, recent retrospective analyses performed on a pooled data set from major clinical trials added more complexity, reporting an unexpected association of KRAS G13D mutation with a better clinical outcome compared with patients who had other KRAS mutations in the first-line and salvage settings, whereas the other independent analysis failed to demonstrate a benefit from panitumumab in patients with the same KRAS G13D mutation. The anti-EGFR monoclonal antibody-associated skin toxicity and the controversial strategies of management also are discussed. In this review, the authors analyze the previous randomized clinical trials and more critically re-evaluate recent trials and subgroup analyses to derive 3 factors that need to be taken into consideration regarding the addition of EGFR-directed monoclonal antibodies to chemotherapy: the preclinical data on mechanisms of action between chemotherapy and anti-EGFR antibodies along with mechanisms of resistance to anti-EGFR antibodies, the role of cross-over events in overall survival data, and the significant dose reductions of chemotherapeutic agents when combined with anti-EGFR agents.

Randomized controlled trial of cetuximab plus chemotherapy for patients with KRAS wild-type unresectable colorectal liver-limited metastases

PURPOSE

To assess the effects of cetuximab plus chemotherapy as first-line treatment for unresectable colorectal liver metastases (CLMs).

PATIENTS AND METHODS

After resection of their primary tumors, patients with KRAS wild-type synchronous nonresectable liver-limited metastases from colorectal cancer were randomly assigned to receive chemotherapy (FOLFIRI [fluorouracil, leucovorin, and irinotecan] or mFOLFOX6 [modified fluorouracil, leucovorin, and oxaliplatin]) plus cetuximab (arm A) or chemotherapy alone (arm B). The primary end point was the rate of patients converted to resection for liver metastases. Secondary end points included tumor response and survival.

RESULTS

The intent-to-treat population comprised 138 patients; 70 patients were randomly assigned to arm A and 68 to arm B. After a median of 25.0 months of follow-up, the 3-year overall survival (OS) rate and median survival time (MST) for all patients were 30% and 24.4 months, respectively. The R0 resection rates for liver metastases were 25.7% (18 of 70 patients) in arm A and 7.4% (five of 68 patients) in arm B, which were significantly different (P < .01). Patients in arm A had improved objective response rates (57.1% v 29.4%; P < .01), increased 3-year OS rate (41% v 18%; P = .013) and prolonged MST (30.9 v 21.0 months; P = .013) compared with those in arm B. In addition, in arm A, patients who had resection of liver metastases had a significantly improved MST (46.4 v 25.7 months; P < .01) compared with those who did not undergo surgery.

CONCLUSION

For patients with initially unresectable KRAS wild-type CLMs, cetuximab combined with chemotherapy improved the resectability of liver metastases and improved response rates and survival compared with chemotherapy alone.

Early tumor shrinkage in patients with metastatic colorectal cancer receiving first-line treatment with cetuximab combined with either CAPIRI or CAPOX: an analysis of the German AIO KRK 0104 trial

PURPOSE

This study investigated the impact of early tumor shrinkage (ETS) on progression-free- (PFS) and overall survival (OS) in patients with metastatic colorectal cancer (mCRC) treated within the AIO KRK 0104 trial as first-line therapy. Moreover, correlations of ETS with clinical characteristics and prognostic markers were evaluated.

PATIENTS AND METHODS

In total, 121 patients were included into this analysis. Patients were treated with cetuximab combined with either CAPIRI or CAPOX. ETS at six weeks was defined as a relative change of ≥ 20% in the sum of the longest diameters of target lesions compared to baseline. Survival times were compared between patients with ETS ≥ 20% versus no-ETS.

RESULTS

ETS ≥ 20% was observed in 59% of all patients with KRAS wild-type tumors. In these patients ETS ≥ 20% was associated with higher overall response rate (82% vs. 19%, p < 0.001). Also, PFS (8.9 vs. 4.7 months, p < 0.001) and OS (31.6 vs. 15.8 months, p = 0.005) were significantly superior in ETS ≥ 20% of patients compared to no-ETS. In patients with KRAS mutant mCRC ETS ≥ 20% neither had an effect on PFS nor OS. Cetuximab-induced skin toxicity correlated with the occurrence of ETS ≥ 20% (p = 0.002).

CONCLUSION

In patients with KRAS wild-type tumors treated with cetuximab plus capecitabine-based chemotherapy ETS ≥ 20% is an important predictor of favorable outcome.

Antitumor activity of pimasertib, a selective MEK 1/2 inhibitor, in combination with PI3K/mTOR inhibitors or with multi-targeted kinase inhibitors in pimasertib-resistant human lung and colorectal cancer cells

The RAS/RAF/MEK/MAPK and the PTEN/PI3K/AKT/mTOR pathways are key regulators of proliferation and survival in human cancer cells. Selective inhibitors of different transducer molecules in these pathways have been developed as molecular targeted anti-cancer therapies. The in vitro and in vivo anti-tumor activity of pimasertib, a selective MEK 1/2 inhibitor, alone or in combination with a PI3K inhibitor (PI3Ki), a mTOR inhibitor (everolimus), or with multi-targeted kinase inhibitors (sorafenib and regorafenib), that block also BRAF and CRAF, were tested in a panel of eight human lung and colon cancer cell lines. Following pimasertib treatment, cancer cell lines were classified as pimasertib-sensitive (IC50 for cell growth inhibition of 0.001 µM) or pimasertib-resistant. Evaluation of basal gene expression profiles by microarrays identified several genes that were up-regulated in pimasertib-resistant cancer cells and that were involved in both RAS/RAF/MEK/MAPK and PTEN/PI3K/AKT/mTOR pathways. Therefore, a series of combination experiments with pimasertib and either PI3Ki, everolimus, sorafenib or regorafenib were conducted, demonstrating a synergistic effect in cell growth inhibition and induction of apoptosis with sustained blockade in MAPK- and AKT-dependent signaling pathways in pimasertib-resistant human colon carcinoma (HCT15) and lung adenocarcinoma (H1975) cells. Finally, in nude mice bearing established HCT15 and H1975 subcutaneous tumor xenografts, the combined treatment with pimasertib and BEZ235 (a dual PI3K/mTOR inhibitor) or with sorafenib caused significant tumor growth delays and increase in mice survival as compared to single agent treatment. These results suggest that dual blockade of MAPK and PI3K pathways could overcome intrinsic resistance to MEK inhibition.

Panitumumab and irinotecan versus irinotecan alone for patients with KRAS wild-type, fluorouracil-resistant advanced colorectal cancer (PICCOLO): a prospectively stratified randomised trial

Background

Therapeutic antibodies targeting EGFR have activity in advanced colorectal cancer, but results from clinical trials are inconsistent and the population in which most benefit is derived is uncertain. Our aim was to assess the addition of panitumumab to irinotecan in pretreated advanced colorectal cancer.

Methods

In this open-label, randomised trial, we enrolled patients who had advanced colorectal cancer progressing after fluoropyrimidine treatment with or without oxaliplatin from 60 centres in the UK. From December, 2006 until June, 2008, molecularly unselected patients were recruited to a three-arm design including irinotecan (control), irinotecan plus ciclosporin, and irinotecan plus panitumumab (IrPan) groups. From June 10, 2008, in response to new data, the trial was amended to a prospectively stratified design, restricting panitumumab randomisation to patients with KRAS wild-type tumours; the results of the comparison between the irinotcan and IrPan groups are reported here. We used a computer-generated randomisation sequence (stratified by previous EGFR targeted therapy and then minimised by centre, WHO performance status, previous oxaliplatin, previous bevacizumab, previous dose modifications, and best previous response) to randomly allocate patients to either irinotecan or IrPan. Patients in both groups received 350 mg/m² intravenous irinotecan every 3 weeks (300 mg/m² if aged ≥70 years or a performance status of 2); patients in the IrPan group also received intravenous panitumumab 9 mg/kg every 3 weeks. The primary endpoint was overall survival in KRAS wild-type patients who had not received previous EGFR targeted therapy, analysed by intention to treat. Tumour DNA was pyrosequenced for KRAS_c.146, BRAF, NRAS, and PIK3CA mutations, and predefined molecular subgroups were analysed for interaction with the effect of panitumumab. This study is registered, number ISRCTN93248876.

Results

Between Dec 4, 2006, and Aug 31, 2010, 1198 patients were enrolled, of whom 460 were included in the primary population of patients with KRAS_c.12–13,61 wild-type tumours and no previous EGFR targeted therapy. 230 patients were randomly allocated to irinotecan and 230 to IrPan. There was no difference in overall survival between groups (HR 1·01, 95% CI 0·83–1·23; p=0·91), but individuals in the IrPan group had longer progression-free survival (0·78, 0·64–0·95; p=0·015) and a greater number of responses (79 [34%] patients vs 27 [12%]; p<0·0001) than did individuals in the irinotecan group. Grade 3 or worse diarrhoea (64 [29%] of 219 patients vs 39 [18%] of 218 patients), skin toxicity (41 [19%] vs none), lethargy (45 [21]% vs 24 [11%]), infection (42 [19%] vs 22 [10%]) and haematological toxicity (48 [22%] vs 27 [12%]) were reported more commonly in the IrPan group than in the irinotecan group. We recorded five treatment-related deaths, two in the IrPan group and three in the irinotecan group.

Interpretation

Adding panitumumab to irinotecan did not improve the overall survival of patients with wild-type KRAS tumours. Further refinement of molecular selection is needed for substantial benefits to be derived from EGFR targeting agents.

Funding

Cancer Research UK, Amgen Inc.

Management of potentially resectable colorectal cancer liver metastases

Colorectal cancer is a very common malignancy worldwide and development of liver metastases, both synchronous or metachronous, is a common event. Of all patients with metastatic colorectal cancer, up to 77% have a liver-only disease and approximately 10%-20% of patients with colorectal liver metastases are considered resectable at the time of diagnosis. Surgical resection of liver metastases remains the best treatment option and it is associated with a survival plateau and a 20%-25% of long-term survivors. Perioperative chemotherapy for resectable liver metastases may improve resecability of liver metastases and disease free survival, but its impact on overall survival is still unclear and more studies are needed. Moreover, preoperative chemotherapy can increase postoperative complications. Further studies are needed to define the role of adjuvant chemotherapy after a R0 resection of liver metastases and to define the criteria for a better selection of patients candidate to hepatectomy. New strategies such as targeted therapies are emerging with promising results. Optimal management requires a multidisciplinary approach, local and systemic, but it is a still pending question. Colorectal liver metastases represent a major challenge for oncologists and surgeons. In this review will be analyzed available data about assessment and management of the patients with potentially resectable colorectal liver metastases.

A review of the treatment options for skin rash induced by EGFR-targeted therapies: Evidence from randomized clinical trials and a meta-analysis

BACKGROUND

Agents targeting the epidermal growth factor receptor (EGFR) are amongst the most extensively used of the targeted agents in the therapy of some of the most common solid tumors. Although they avoid many of the classic side effects associated with cytotoxic chemotherapy, they are associated with unpleasant cutaneous toxicities which can affect treatment compliance and impinge on patient quality of life. To date, despite a plethora of consensus recommendations, expert opinions and reviews, there is a paucity of evidence-based guidance for the management of the skin rash that occurs in the treatment of patients receiving EGFR-targeted therapies.

METHODS

A literature search was conducted as a first step towards investigating not only an evidence-based approach to the management of skin rash, but also with a view to designing future randomized trials.

RESULTS

The literature search identified seven randomized trials and a meta-analysis was conducted using the data from four of these trials involving oral antibiotics. The meta-analysis of the data from these four trials suggests that prophylactic antibiotics might reduce the relative risk of severe rash associated with EGFR-targeted agents by 42-77%. Vitamin K cream was also identified as having a potential role in the management EGFR-targeted agent induced rash.

CONCLUSIONS

This review and meta-analysis clearly identify the need for further randomized studies of the role of oral antibiotics in this setting. The results of the ongoing randomized trials of the topical application of vitamin K cream plus or minus doxycycline and employing prophylactic versus reactive strategies are eagerly awaited.

Targeted sequencing of cancer-related genes in colorectal cancer using next-generation sequencing

Recent advance in sequencing technology has enabled comprehensive profiling of genetic alterations in cancer. We have established a targeted sequencing platform using next-generation sequencing (NGS) technology for clinical use, which can provide mutation and copy number variation data. NGS was performed with paired-end library enriched with exons of 183 cancer-related genes. Normal and tumor tissue pairs of 60 colorectal adenocarcinomas were used to test feasibility. Somatic mutation and copy number alteration were analyzed. A total of 526 somatic non-synonymous sequence variations were found in 113 genes. Among these, 278 single nucleotide variations were 232 different somatic point mutations. 216 SNV were 79 known single nucleotide polymorphisms in the dbSNP. 32 indels were 28 different indel mutations. Median number of mutated gene per tumor was 4 (range 0-23). Copy number gain (>X2 fold) was found in 65 genes in 40 patients, whereas copy number loss ( Collapse

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MESH Headings

• Adult
• Aged
• Aged, 80 and over
• Colorectal Neoplasms/genetics
• Colorectal Neoplasms/metabolism
• Colorectal Neoplasms/pathology
• DNA Copy Number Variations
• Female
• Genomics
• High-Throughput Nucleotide Sequencing
• Humans
• INDEL Mutation
• Male
• Middle Aged
• Mutation
• Neoplasm Staging
• Oncogenes
• Polymorphism, Single Nucleotide
• Reproducibility of Results
• Signal Transduction

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Affiliation(s)

Sae-Won Han Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea
Hwang-Phill Kim Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea
Jong-Yeon Shin Genomic Medicine Institute, Medical Research Center, Seoul National University, Seoul, Korea Psoma Therapeutics Inc., Seoul, Korea
Eun-Goo Jeong Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea
Won-Chul Lee Genomic Medicine Institute, Medical Research Center, Seoul National University, Seoul, Korea Department of Biomedical Sciences, Seoul National University Graduate School, Seoul, Korea
Kyung-Hun Lee Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea
Jae-Kyung Won Department of Pathology, Seoul National University Hospital, Seoul, Korea
Tae-Yong Kim Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea
Do-Youn Oh Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea
Seock-Ah Im Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea
Yung-Jue Bang Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea
Seung-Yong Jeong Department of Surgery, Seoul National University Hospital, Seoul, Korea
Kyu Joo Park Department of Surgery, Seoul National University Hospital, Seoul, Korea
Jae-Gahb Park Department of Surgery, Seoul National University Hospital, Seoul, Korea
Gyeong Hoon Kang Department of Pathology, Seoul National University Hospital, Seoul, Korea
Jeong-Sun Seo Genomic Medicine Institute, Medical Research Center, Seoul National University, Seoul, Korea Department of Biomedical Sciences, Seoul National University Graduate School, Seoul, Korea Department of Biochemistry, Seoul National University College of Medicine, Seoul, Korea Macrogen Inc., Seoul, Korea
Jong-Il Kim Genomic Medicine Institute, Medical Research Center, Seoul National University, Seoul, Korea Psoma Therapeutics Inc., Seoul, Korea Department of Biomedical Sciences, Seoul National University Graduate School, Seoul, Korea Department of Biochemistry, Seoul National University College of Medicine, Seoul, Korea
Tae-You Kim Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea Department of Biomedical Sciences, Seoul National University Graduate School, Seoul, Korea Department of Molecular Medicine & Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Korea

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Standardized added metabolic activity (SAM) IN ¹⁸F-FDG PET assessment of treatment response in colorectal liver metastases

PURPOSE

Standardized added metabolic activity (SAM) is a PET parameter for assessing the total metabolic load of malignant processes, avoiding partial volume effects and lesion segmentation. The potential role of this parameter in the assessment of response to chemotherapy and bevacizumab was tested in patients with metastatic colorectal cancer with potentially resectable liver metastases (mCRC).

METHODS

(18)F-FDG PET/CT was performed in 18 mCRC patients with liver metastases before treatment and after five cycles of FOLFOX/FOLFIRI and bevacizumab. Of the 18 patients, 16 subsequently underwent resection of liver metastases. Baseline and follow-up SUVmax, and SAM as well as reduction in SUVmax (∆SUVmax) and SAM (∆SAM) of all liver metastases were correlated with morphological response, and progression-free and overall survival (PFS and OS).

RESULTS

A significant reduction in metabolic activity of the liver metastases was seen after chemotherapy with a median ∆SUVmax of 25.3% and ∆SAM of 94.5% (p = 0.033 and 0.003). Median baseline SUVmax and SAM values were significantly different between morphological responders and nonresponders (3.8 vs. 7.2, p = 0.021; and 34 vs. 211, p = 0.002, respectively), but neither baseline PET parameters nor morphological response was correlated with PFS or OS. Follow-up SUVmax and SAM as well as ∆SAM were found to be prognostic factors. The median PFS and OS in the patient group with a high follow-up SUVmax were 10.4 months and 32 months, compared to a median PFS of 14.7 months and a median OS which had not been reached in the group with a low follow-up SUVmax (p = 0.01 and 0.003, respectively). The patient group with a high follow-up SAM and a low ∆SAM had a median PFS and OS of 9.4 months and 32 months, whereas the other group had a median PFS of 14.7 months and a median OS which had not been reached (p = 0.002 for both PFS and OS).

CONCLUSION

(18)F-FDG PET imaging is a useful tool to assess treatment response and predict clinical outcome in patients with mCRC who undergo chemotherapy before liver metastasectomy. Follow-up SUVmax, follow-up SAM and ∆SAM were found to be significant prognostic factors for PFS and OS.

Systemic treatment of liver metastases from colorectal cancer

Patients presenting with synchronous or metachronous colorectal cancer liver metastases (CLM) should be evaluated for multimodal management with curative intent. Preoperative systemic chemotherapy shows beneficial impact on adjuvant progression-free survival and also borderline on overall survival, without significantly increasing initially R0 resectable patients postoperative complication rates. Postoperative chemotherapy recommended based on the perioperative trial experience for those patients achieving at least stable disease during preoperative chemotherapy, or based on the adjuvant trials for patients receiving upfront resection. 'Borderline' resectable CLM, preoperative chemotherapy plays an important role in both in achievement of a resectable status and improvement of prognosis. Recent 4 drug combinations demonstrated response rates up to 80% even for advanced disease and are thus promising regimens for further evaluation in patients with resectable or unresectable liver-limited (+/- lung) disease.

Improvement in survival of metastatic colorectal cancer: are the benefits of clinical trials reproduced in population-based studies?

AIM OF THE STUDY

To describe trends in survival of non-resectable metastatic colorectal cancer (MCRC) over a 34-year period in a French population-based registry taking into account major advances in medical therapy.

PATIENTS AND METHODS

3804 patients with non-resectable metastatic colorectal cancer diagnosed between 1976 and 2009 were included. Three periods (1976-96, 1997-2004 and 2005-09) were considered.

RESULTS

The proportion of patients receiving chemotherapy dramatically increased from 19% to 57% between the first two periods, then increased steadily thereafter reaching 59% during the last period (p<0.001). Median relative survival increased from 5.9 months during the 1976-96 period to 10.2 months during the 1997-2004 period but, despite the availability of targeted therapies, remained at 9.5 months during the 2005-09 period. During the last study period, less than 10% of elderly patients received targeted therapies compared to more than 40% for younger patients. Their median relative survival was 5.0 months compared to 15.6 months in younger patients.

CONCLUSION

There was an improvement in survival in relation with the increased use of more effective medical treatment. However, at a population-based level, patients are not all treated equally and most of them, especially the elderly, do not benefit from the most up-to-date treatment options.

Why do targeted agents not work in the adjuvant setting in colon cancer?

The standard adjuvant treatment of stage III and high-risk stage II colon cancer is to administer 6 months of oxaliplatin- and fluorouracil-containing chemotherapy. However, nearly a third of stage III patients still recur. The positive results of cetuximab and bevacizumab added to chemotherapy in patients with metastatic colorectal cancer formed the basis to explore the role of these agents in the adjuvant setting. However, two adjuvant trials with bevacizumab and one adjuvant trial with cetuximab have failed to show any benefit of adding these agents to standard chemotherapy. Although reasons for the negative results remain unknown, the divergent effects of bevacizumab and cetuximab in early- versus advanced stage colon-cancer reinforce the notion that adjuvant and metastatic settings represent distinct diseases that require different treatments. This article summarizes the results of the adjuvant bevacizumab and cetuximab trials and discusses the possible explanations why molecularly targeted agents had no impact on improving the outcomes of adjuvant treatment of colon cancer.

Improving outcomes in colorectal cancer: where do we go from here?

Colorectal cancer (CRC) places a considerable burden on individuals and society in Europe, being the second most common cause of cancer-related death in the region. While earlier diagnosis and advances in treatment have considerably improved survival in recent years, further progress is needed. One of the greatest challenges associated with the treatment of CRC is the fact that current therapies for advanced disease are not curative, necessitating treatment for many years and placing a significant healthcare burden on society. To reduce the burden of CRC, care delivery must be more efficient and cost-effective. In particular, development of adequate screening programmes is needed, along with chemo-preventative strategies and newer, more active therapies. Further challenges include the lack of optimal selection of patients for adjuvant therapy, identification of the most appropriate target populations for current treatments and the optimum sequence for new molecular targeted agents. This article outlines current developments and unmet needs in CRC, and provides a detailed vision for improvements in the management of the disease. Implementation of some of these strategies will go some way to improving outcomes for patients with CRC.

Epidermal growth factor receptor (EGFR)-RAS signaling pathway in penile squamous cell carcinoma

Penile Squamous Cell Carcinoma (SCC) is a rare cancer with poor prognosis and limited response to conventional chemotherapy. The genetic and epigenetic alterations of Epidermal Growth Factor Receptor (EGFR)-RAS-RAF signaling in penile SCC are unclear. This study aims to investigate four key members of this pathway in penile SCC. We examined the expression of EGFR and RAS-association domain family 1 A (RASSF1A) as well as the mutation status of K-RAS and BRAF in 150 cases of penile SCC. EGFR and RASSF1A expression was evaluated by immunohistochemistry. KRAS mutations at codons 12 and 13, and the BRAF mutation at codon 600 were analyzed on DNA isolated from formalin fixed paraffin embedded tissues by direct genomic sequencing. EGFR expression was positive in all specimens, and its over-expression rate was 92%. RASSF1A expression rate was only 3.42%. Significant correlation was not found between the expression of EGFR or RASSF1A and tumor grade, pT stage or lymph node metastases. The detection of KRAS and BRAF mutations analysis was performed in 94 and 83 tumor tissues, respectively. We found KRAS mutation in only one sample and found no BRAF V600E point mutation. In summary, we found over-expression of EGFR in the majority cases of penile SCC, but only rare expression of RASSF1A, rare KRAS mutation, and no BRAF mutation in penile SCC. These data suggest that anti-EGFR agents may be potentially considered as therapeutic options in penile SCC.