Karoline Horisberger

KRAS and BRAF mutations and PTEN expression do not predict efficacy of cetuximab-based chemoradiotherapy in locally advanced rectal cancer.

PURPOSE Mutations in KRAS and BRAF genes as well as the loss of expression of phosphatase and tensin homolog (PTEN) (deleted on chromosome 10) are associated with impaired activity of antibodies directed against epidermal growth factor receptor in patients with metastatic colorectal cancer. The predictive and prognostic value of the KRAS and BRAF point mutations as well as PTEN expression in patients with locally advanced rectal cancer (LARC) treated with cetuximab-based neoadjuvant chemoradiotherapy is unknown. METHODS AND MATERIALS We have conducted phase I and II trials of the combination of weekly administration of cetuximab and irinotecan and daily doses of capecitabine in conjunction with radiotherapy (45 Gy plus 5.4 Gy) in patients with LARC (stage uT3/4 or uN+). The status of KRAS and BRAF mutations was determined with direct sequencing, and PTEN expression status was determined with immunohistochemistry testing of diagnostic tumor biopsies. Tumor regression was evaluated by using standardized regression grading, and disease-free survival (DFS) was calculated according to the Kaplan-Meier method. RESULTS A total of 57 patients were available for analyses. A total of 31.6% of patients carried mutations in the KRAS genes. No BRAF mutations were found, while the loss of PTEN expression was observed in 9.6% of patients. Six patients achieved complete remission, and the 3-year DFS rate was 73%. No correlation was seen between tumor regression or DFS rate and a single marker or a combination of all markers. CONCLUSIONS In the present series, no BRAF mutation was detected. The presence of KRAS mutations and loss of PTEN expression were not associated with impaired response to cetuximab-based chemoradiotherapy and 3-year DFS.

Retrorectal tumors: Excision by transanal endoscopic microsurgery

Tumours within the retrorectal space are uncommon. Due to their rarity and diverse symptoms they are often misdiagnosed or mistreated. We report three cases of women presenting a variety of symptoms including increased rectal pain, recurrent abscesses/fistulas and constipation. Upon clinical examination and further investigations using MR scan, endorectal ultrasound and endoscopy, a retrorectal mass was suspected in all three cases. In order to achieve a complete excision of the tumor while minimizing trauma, transanal endoscopic microsurgery (TEM) was performed. The histology of the multicystic tumor revealed in all three cases a tailgut cyst. As far as we know this is the first report describing the use of TEM for surgical treatment of tumors located in the retrorectal space.

Expression of Transketolase like gene 1 (TKTL1) predicts disease-free survival in patients with locally advanced rectal cancer receiving neoadjuvant chemoradiotherapy

BackgroundFor patients with locally advanced rectal cancer (LARC) neoadjuvant chemoradiotherapy is recommended as standard therapy. So far, no predictive or prognostic molecular factors for patients undergoing multimodal treatment are established. Increased angiogenesis and altered tumour metabolism as adaption to hypoxic conditions in cancers play an important role in tumour progression and metastasis. Enhanced expression of Vascular-endothelial-growth-factor-receptor (VEGF-R) and Transketolase-like-1 (TKTL1) are related to hypoxic conditions in tumours. In search for potential prognostic molecular markers we investigated the expression of VEGFR-1, VEGFR-2 and TKTL1 in patients with LARC treated with neoadjuvant chemoradiotherapy and cetuximab.MethodsTumour and corresponding normal tissue from pre-therapeutic biopsies of 33 patients (m: 23, f: 10; median age: 61 years) with LARC treated in phase-I and II trials with neoadjuvant chemoradiotherapy (cetuximab, irinotecan, capecitabine in combination with radiotherapy) were analysed by quantitative PCR.ResultsSignificantly higher expression of VEGFR-1/2 was found in tumour tissue in pre-treatment biopsies as well as in resected specimen after neoadjuvant chemoradiotherapy compared to corresponding normal tissue. High TKTL1 expression significantly correlated with disease free survival. None of the markers had influence on early response parameters such as tumour regression grading. There was no correlation of gene expression between the investigated markers.ConclusionHigh TKTL-1 expression correlates with poor prognosis in terms of 3 year disease-free survival in patients with LARC treated with intensified neoadjuvant chemoradiotherapy and may therefore serve as a molecular prognostic marker which should be further evaluated in randomised clinical trials.

Amplicon Sequencing of Colorectal Cancer: Variant Calling in Frozen and Formalin-Fixed Samples

Next generation sequencing (NGS) is an emerging technology becoming relevant for genotyping of clinical samples. Here, we assessed the stability of amplicon sequencing from formalin-fixed paraffin-embedded (FFPE) and paired frozen samples from colorectal cancer metastases with different analysis pipelines. 212 amplicon regions in 48 cancer related genes were sequenced with Illumina MiSeq using DNA isolated from resection specimens from 17 patients with colorectal cancer liver metastases. From ten of these patients, paired fresh frozen and routinely processed FFPE tissue was available for comparative study. Sample quality of FFPE tissues was determined by the amount of amplifiable DNA using qPCR, sequencing libraries were evaluated using Bioanalyzer. Three bioinformatic pipelines were compared for analysis of amplicon sequencing data. Selected hot spot mutations were reviewed using Sanger sequencing. In the sequenced samples from 16 patients, 29 non-synonymous coding mutations were identified in eleven genes. Most frequent were mutations in TP53 (10), APC (7), PIK3CA (3) and KRAS (2). A high concordance of FFPE and paired frozen tissue samples was observed in ten matched samples, revealing 21 identical mutation calls and only two mutations differing. Comparison of these results with two other commonly used variant calling tools, however, showed high discrepancies. Hence, amplicon sequencing can potentially be used to identify hot spot mutations in colorectal cancer metastases in frozen and FFPE tissue. However, remarkable differences exist among results of different variant calling tools, which are not only related to DNA sample quality. Our study highlights the need for standardization and benchmarking of variant calling pipelines, which will be required for translational and clinical applications.

Dynamics of Genome Alterations in Crohn's Disease–Associated Colorectal Carcinogenesis

Purpose: Patients with inflammatory bowel diseases, that is, ulcerative colitis and Crohns disease (CD), face an increased risk of developing colorectal cancer (CRC). Evidence, mainly from ulcerative colitis, suggests that TP53 mutations represent an initial step in the progression from inflamed colonic epithelium to CRC. However, the pathways involved in the evolution of CRC in patients with CD are poorly characterized. Experimental Design: Here, we analyzed 73 tissue samples from 28 patients with CD-CRC, including precursor lesions, by targeted next-generation sequencing of 563 cancer-related genes and array-based comparative genomic hybridization. The results were compared with 24 sporadic CRCs with similar histomorphology (i.e., mucinous adenocarcinomas), and to The Cancer Genome Atlas data (TCGA). Results: CD-CRCs showed somatic copy-number alterations (SCNAs) similar to sporadic CRCs with one notable exception: the gain of 5p was significantly more prevalent in CD-CRCs. CD-CRCs had a distinct mutation signature: TP53 (76% in CD-CRCs vs. 33% in sporadic mucinous CRCs), KRAS (24% vs. 50%), APC (17% vs. 75%), and SMAD3 (3% vs. 29%). TP53 mutations and SCNAs were early and frequent events in CD progression, while APC, KRAS, and SMAD2/4 mutations occurred later. In four patients with CD-CRC, at least one mutation and/or SCNAs were already present in non-dysplastic colonic mucosa, indicating occult tumor evolution. Conclusions: Molecular profiling of CD-CRCs and precursor lesions revealed an inflammation-associated landscape of genome alterations: 5p gains and TP53 mutations occurred early in tumor development. Detection of these aberrations in precursor lesions may help predicting disease progression and distinguishes CD-associated from sporadic colorectal neoplasia. Clin Cancer Res; 24(20); 4997–5011. ©2018 AACR.

Clinical and Histopathologic Features of Colorectal Adenocarcinoma in Crohn’s Disease

Goals: The aim of this study was to assess the histopathologic characteristics of colorectal carcinomas (CRC) in patients with Crohn’s disease (CD). Background: A higher frequency of microsatellite instability (MSI) is seen in mucinous compared with nonmucinous CRC which suggests that its pathogenesis involves distinct molecular pathways. Several publications reported a higher percentage of mucinous adenocarcinoma in CD patients with CRC. So far, there has been no investigation of MSI in CD patients with mucinous CRC. Study: The medical records of patients who underwent surgery for CRC were reviewed and those with a history of CD identified. The data of histologic classification and MSI status of the tumor were investigated. Results: Fourteen patients with CD-associated CRC were identified (5 female, 9 male) resulting in 20 CRC in total. Histologic investigation revealed 7 adenocarcinomas without a mucinous or signet ring cell component. All other CRCs harbored a mucinous (n=11) and/or signet ring cell (n=6) component. All tumors assessed for MSI were found to be microsatellite stable. Conclusions: Our data indicate that CRCs with signet ring cell and mucinous components were much more common in patients with CD than in patients with sporadic CRC. This observation suggests that CRC in CD represent an own entity with distinct histopathologic and molecular features. This may implicate potential consequences for diagnosis and therapy of CRC in CD in the future as well as new factors to identify patients with an increased risk for developing CRC in CD.

False teeth in an apple core: Unusual presentation of a colorectal carcinoma

Introduction Ingestion of foreign bodies is common amongst the elderly. Although most foreign bodies pass through the gastrointestinal tract without consequence some cause complications including bowel perforation. Presentation of case We present a case of denture ingestion that lead to the diagnosis of an unsuspected colorectal cancer. The patient underwent radical surgery to remove the tumor and the ingested denture. The operation and recovery were uneventful. Discussion Complications from ingested foreign bodies mostly occur at points of anatomical intestinal tapering. However, tumors of the gastro-intestinal tract can also lead to obstructions and other complications. As the incidence of tumors increases with age, this possibility should be considered in the differential diagnosis of unusual situation. Conclusion Although impaction of a foreign body in a gastro-intestinal tumor is very rare, our case suggests close follow-up is prudent in the elderly should a foreign body be ingested.

Abdominopelvic actinomycosis in three different locations with invasion of the abdominal wall and ureteric obstruction: An uncommon presentation

Highlights • We present an uncommon case of extended abdominoplevic actinomycosis.• The patient underwent successful surgical and subsequent long-term antibiotic therapy.• The possibility of a malignant process required radical resection.• Actinomycisis should be considered when a pelvic mass is associated with use of an intrauterine device.

Transanal Endoscopic Microsurgery - State of the Art

The first description of surgery for rectal cancer was reported by the French surgeon Lisfranc who described a total of nine patients operated trough a perineal-transanal approach (Lisfranc, 1830). Although more recently gaining popularity, transanal techniques have long been used for the treatment of rectal diseases and were promoted by the work of Sir Alan Parks at St. Marks Hospital in London in the 1950s (Parks, 1970). This conventional surgical approach is well suited for the management of selected low rectal lesions; on the contrary, removal of lesions in the middle and upper rectum are less feasible due to the limited accessibility and inadequate exposure afforded by standard instrumentation. For these reasons, those more proximal lesions have historically been tackled by more radical surgical approaches, like abdominal low anterior, abdominoperineal, transsacral, and transsphincteric resections.

Side Effects of Neoadjuvant Treatment in Locally Advanced Rectal Cancer

Neoadjuvant treatment of locally advanced rectal cancer patients provides undisputable advantages regarding local control (1; 2), and it seems to afford the benefit of survival in patients with preoperative complete regression (3; 4). Furthermore, local control is an important feature in life quality of rectal cancer patients. However, due to the perspicuous interests in oncological effects, the acute and moreover late side effects tend to be neglected. The consequence is that especially late side effects have probably been underestimated until now. Many patients would perceive a permanent stoma and loss of the anal sphincter as a stigma that lowers their self-esteem (5). Hence, sphincter preservation is a major request of the patients and developed to an important surgical concern. In fact, patients are willing to trade a considerable amount of survival to avoid a colostomy (6). And more than this, they are also disposed to trade survival in order to avoid chemotherapy (6). Though, with regard to oncological and surgical outcome control late results are important. For all patients quality of life matters are fundamental. This particularly counts for those patients who show an incomplete regression or none and therefore do have only limited benefit from the treatment.