Personalized treatment for advanced colorectal cancer: KRAS and beyond

Appendiceal Goblet Cell Carcinoma: Role of Cytoreductive Surgery (CRS) and Hyperthermic Intraperitoneal Chemotherapy (HIPEC)

Goblet cell carcinoma (GCC) encompasses a separate entity in appendiceal neoplasms with mixed glandular and neuro-endocrine pathological features. GCC mostly presents as an acute appendicitis duo to luminal obstruction or as an incidental finding on the surgical appendectomy specimen. In case of tumour perforation or presence of other risk factors, guidelines suggest additional treatment with a completing right hemicolectomy or cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC). We report the case of a 77-year-old male with symptoms of appendicitis for which an appendectomy was performed. The appendix was ruptured during the procedure. There was an incidental finding of GCC on the pathological specimen. Because of possible tumour soiling, the patient received a prophylactic CRS-HIPEC. A literature review was performed to investigate the potential role for CRS-HIPEC as a curative treatment in patients with GCC. GCC of the appendix is an aggressive type of tumour with a high risk of peritoneal and systemic dissemination. CRS and HIPEC is a treatment option: both in a prophylactic setting and in patients with established peritoneal metastases.

Imaging predictors of BRAF mutation in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is one of the leading causes of cancer deaths and is associated with various genetic mutations. BRAF mutations, found in approximately 10% of all CRCs, are associated with negative predictive outcomes. The goal of this study was to assess the relationship between the imaging findings and BRAF statuses of CRC patients.

MATERIALS AND METHODS

The study population was colorectal cancer patients who underwent biopsy or surgery in a single institution from September 2004 to October 2018, and in whom the pathologic specimens were tested for BRAF mutation. The exclusion criteria were (1) patients without pre-operative cross-sectional imaging, and (2) patients whose tumors were invisible on imaging. Two hundred and eighty-three patients met the inclusion criteria. Among them, 128 were excluded, and a total of 155 patients were enrolled in the study.

RESULTS

BRAF mutations were significantly more common in female patients (p = 0.007). Patients with mutated BRAF were significantly older than those with wild-type BRAF (p = 0.001). BRAF-mutant tumors were predominant in right-sided colon (p = 0.001) with higher numbers of polypoid- or mass-like morphology (p = 0.019) and heterogeneous enhancement (p = 0.009). Compared to their wild-type counterparts, BRAF-mutated CRCs have a lower occurrence of non-peritoneal, and overall metastases (p = 0.013 and p = 0.004, respectively). Logistic regression analysis showed three significant factors for the prediction of BRAF mutations in CRC patients: right-sided location (p = 0.002), heterogeneous tumor enhancement (p = 0.039), and lack of non-peritoneal metastasis (p = 0.043).

CONCLUSION

By recognizing the specific imaging features of BRAF-mutant CRCs, it would be possible to identify a patient who has a higher risk of carrying BRAF mutation.

Promising Therapeutic Efficacy of GC1118, an Anti-EGFR Antibody, against KRAS Mutation-Driven Colorectal Cancer Patient-Derived Xenografts

Epidermal growth factor receptor (EGFR)-targeted monoclonal antibodies, including cetuximab and panitumumab, are used to treat metastatic colorectal cancer (mCRC). However, this treatment is only effective for a small subset of mCRC patients positive for the wild-type KRAS GTPase. GC1118 is a novel, fully humanized anti-EGFR IgG1 antibody that displays potent inhibitory effects on high-affinity EGFR ligand-induced signaling and enhanced antibody-mediated cytotoxicity. In this study, using 51 CRC patient-derived xenografts (PDXs), we showed that KRAS mutants expressed remarkably elevated autocrine levels of high-affinity EGFR ligands compared with wild-type KRAS. In three KRAS-mutant CRCPDXs, GC1118 was more effective than cetuximab, whereas the two agents demonstrated comparable efficacy against three wild-type KRAS PDXs. Persistent phosphatidylinositol-3-kinase (PI3K)/AKT signaling was thought to underlie resistance to GC1118. In support of these findings, a preliminary improved anti-cancer response was observed in a CRC PDX harboring mutated KRAS with intrinsically high AKT activity using GC1118 combined with the dual PI3K/mammalian target of rapamycin (mTOR)/AKT inhibitor BEZ-235, without observed toxicity. Taken together, the superior antitumor efficacy of GC1118 alone or in combination with PI3K/mTOR/AKT inhibitors shows great therapeutic potential for the treatment of KRAS-mutant mCRC with elevated ratios of high- to low-affinity EGFR ligands and PI3K-AKT pathway activation.

Oral mucositis associated with anti-EGFR therapy in colorectal cancer: single institutional retrospective cohort study

Background

Chemotherapy-induced oral mucositis impairs the quality of life. The difference in severity of oral mucositis between different anti-epidermal growth factor receptor (EGFR) antibodies combined with cytotoxic drugs in colorectal cancer is unclear. The aim of this study was to investigate the differences in oral mucositis between panitumumab (Pmab) and cetuximab (Cmab) combined with 5-fluorouracil (5-FU).

Methods

We conducted a retrospective cohort study. A total of 75 colorectal cancer outpatients treated with an anti-EGFR antibody combined with FOLFOX, FOLFIRI, or 5-FU/leucovorin as the first- to third-line treatment were included. The primary endpoint was the incidence of grade 2–3 oral mucositis. The secondary endpoint was the time to onset of oral mucositis. We also compared the incidence of toxicities of interest, skin toxicity, hypomagnesaemia and neutropenia, and time to treatment failure (TTF) between the two groups.

Results

Thirty-two patients treated with Pmab and 43 patients treated with Cmab were evaluated. Patient characteristics were similar between the two groups. The incidence of grade 2–3 oral mucositis was significantly higher with Pmab than with Cmab (31.3% vs 9.3%, P < 0.05). Moreover, the incidence of grade 3 oral mucositis was significantly higher in patients treated with Pmab (18.8% vs 0%, P < 0.01). The mean (SD) cycles to onset of the worst oral mucositis was 3.0 (2.9) in the Pmab group and 2.3 (1.7) in the Cmab group (P = 0.29). Oral mucositis was characterized by glossitis and cheilitis. The incidences of other toxicities were the following (Pmab vs Cmab): grade 2–3 skin toxicity: 68.8% vs 74.4% (P = 0.61), grade 2–3 hypomagnesaemia: 9.3% vs 7.0% (P = 1.00), grade 3–4 neutropenia: 28.1% vs 37.2% (P = 0.46). The median TTF was not significantly different, i.e., 223 days vs 200 days (P = 0.39) for Pmab vs Cmab.

Conclusions

Pmab-based chemotherapy resulted in significantly higher grades of oral mucositis compared with Cmab-based chemotherapy. The oral condition should be monitored carefully and early supportive care should be provided for patients treated with Pmab-based chemotherapy.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4862-z) contains supplementary material, which is available to authorized users.

Prognostic value of amphiregulin and epiregulin mRNA expression in metastatic colorectal cancer patients

Epidermal growth factor receptor (EGFR) and its ligands amphiregulin (AREG) and epiregulin (EREG) play a central role in the development of colorectal cancer, but the prognostic values of AREG and EREG are controversial. We conducted a meta-analysis of studies that investigated AREG and/or EREG mRNA levels in primary tumors to determine their prognostic value in metastatic colorectal cancer (mCRC). In addition, RAS status was assessed. Relevant articles were identified by searching the EMBASE, PubMed, and Cochrane Library databases. Hazard ratios (HR) with 95% confidence intervals (CIs) were calculated using a random-effects model. Nine studies involving 2167 patients were included in this meta-analysis. High AREG expression was associated with longer overall survival (OS) and progression-free survival (PFS). High EREG expression was also associated with prolonged OS and PFS. In RAS wild-type (WT) patients who received anti-EGFR therapy, high AREG and EREG expression was associated with longer OS. Our results indicate that high AREG and EREG mRNA expression are independent favorable prognostic biomarkers in mCRC. The expression of these ligands should be considered when evaluating prognoses in RAS-WT patients receiving anti-EGFR therapy.

The Report of KRAS Mutation and NRAS Wild Type in a Patient with Thyroid Metastasis from Colon Cancer: a Rare Case Report

Colorectal cancer (CRC) metastasis to the thyroid gland is rare. Here we report a 45 yr-old man in western Iran referred to Hematology Clinic, Kermanshah City, Iran in March 2014 with complaint of exertional dyspnea, multi-nodular goiter as well as complaint of exertional dyspnea, and multi-nodular goiter. His history included a low anterior resection of rectum in 9 months ago for a high-risk stage II rectal adenocarcinoma. He did not show clinical signs of hyperthyroidism other than thyroid enlargement. In thyroid nodule the FNA cytology, pathology reported anaplastic thyroid malignancy. Pathologists reported final diagnosis of colorectal metastasis of thyroid gland. Then due to metastatic pattern of disease, his pathology was evaluated for RAS molecular assay. In the patients of metastatic CRC, RAS testing is the first step to identify those patients that could benefit from anti-EGFR monoclonal antibodies treatment.

Prospective noninterventional study on the use of panitumumab monotherapy in patients with recurrent or progressive colorectal cancer: the VECTIS study

Purpose

Epidermal growth factor receptor-targeted monoclonal antibodies are active as monotherapy beyond second-line treatment. Skin toxicities (STs) are common during treatment, and a positive association between ST severity and patient outcome has been reported. This study collected information on panitumumab monotherapy use in patients with KRAS exon 2 wild-type metastatic colorectal cancer in clinical practice.

Methods

This open-label, prospective, observational, noninterventional study included adult patients who had failed prior chemotherapy with 5-fluorouracil, oxaliplatin, and irinotecan. Patients received panitumumab monotherapy (6 mg/kg every 2 weeks) for ≤18 cycles. Effectiveness was assessed as disease control rate (DCR), tumor response, and freedom from progression. The incidence of ST and other adverse drug reactions (ADRs) was recorded, as were Eastern Cooperative Oncology Group performance status (ECOG PS) and quality of life. The KRAS analysis process was also evaluated.

Findings

The full analysis set included 632 patients (64.6% male; mean age, 62.3 years), who completed a mean of 9.6 panitumumab cycles. ST, mainly grade 1/2, occurred in 84.3% of patients, 82.7% of whom required treatment. Nonskin ADRs occurred in 3.5% of patients. By the end of treatment, the DCR was 58.9% overall, and was 53.8% and 62.7%, respectively in patients with ST grade 0/1 and grade 2/3. Significant associations were observed between maximum ST grade and best response (P=0.0009), DCR (P=0.0046), tumor response (P=0.0002), and freedom from progression (P=0.0084). At the end of the study, 67.4% of the patients had an ECOG PS of 0/1. Quality of life was rated as “very good” or “good” in 70.3% of patients. Mean time to obtain KRAS results was 18.2 days; satisfaction with different aspects of KRAS testing was “very good” or “good” in 80%–97% of patients.

Conclusion

Panitumumab monotherapy showed adequate effectiveness and safety in patients with heavily pretreated KRAS exon 2 wild-type metastatic colorectal cancer. The most common ADR was grade 1/2 ST.

Standard chemotherapy with cetuximab for treatment of colorectal cancer

AIM: To review and assess the evidence related to cetuximab treatment in metastatic colorectal cancer (mCRC) with regard to KRAS status.

METHODS: PubMed, EMBASE, Cochrane database and American Society of Clinical Oncology meeting abstracts were searched for randomized controlled trials (RCTs) reporting the effect of KRAS status on efficacy of chemotherapy regimen with or without cetuximab in mCRC. Baseline information such as sex and age was summarized from the included studies. Hazard ratios of progression-free survival (PFS) and overall survival (OS) as well as objective response based on KRAS status were extracted for analysis.

RESULTS: A total of 8 RCTs with 6780 patients were included. The combined analysis showed that cetuximab failed to improve the OS and PFS in patients with mCRC. However, in subgroup analysis, the pooled data showed that addition of cetuximab to irinotecan containing chemotherapy regimen was sufficient to improve OS and PFS in wild-type KRAS mCRC patients, but not in patients with mutant-type KRAS. The addition of cetuximab increased the incidence of adverse events such as diarrhea, rash, skin toxicity/rash, and nausea and vomiting. There was no significant publication bias existing in the included studies.

CONCLUSION: The clinical benefit of cetuximab was only confirmed in patients with wild-type KRAS. KRAS status could be considered a biomarker of efficacy of cetuximab.

A novel approach to detect KRAS/BRAF mutation for colon cancer: Highly sensitive simultaneous detection of mutations and simple pre-treatment without DNA extraction

It has been reported that colon cancer patients with KRAS and BRAF mutations that lie downstream of epidermal growth factor receptor (EGFR) acquire resistance against therapy with anti-EGFR antibodies, cetuximab and panitumumab. On the other hand, some reports say KRAS codon 13 mutation (p.G13D) has lower resistance against anti-EGFR antibodies, thus there is a substantial need for detection of specific KRAS mutations. We have established a state-of-theart measurement system using QProbe (QP) method that allows simultaneous measurement of KRAS codon 12/13, p.G13D and BRAF mutation, and compared this method against Direct Sequencing (DS) using 182 specimens from colon cancer patients. In addition, 32 biopsy specimens were processed with a novel pre-treatment method without DNA purification in order to detect KRAS/BRAF. As a result of KRAS mutation measurement, concordance rate between the QP method and DS method was 81.4% (144/177) except for the 5 specimens that were undeterminable. Among them, 29 specimens became positive with QP method and negative with DS method. BRAF was measured with QP method only, and the mutation detection rate was 3.9% (6/153). KRAS measurement using a simple new pre-treatment method without DNA extraction resulted in 31 good results out of 32, all of them matching with the DS method. We have established a simple but highly sensitive simultaneous detection system for KRAS/BRAF. Moreover, introduction of the novel pre-treatment technology eliminated the inconvenient DNA extraction process. From this research achievement, we not only anticipate quick and accurate results returned in the clinical field but also contribution in improving the test quality and work efficiency.