[The two-in-one hit model of the short-cut carcinogenesis of colorectal carcinomas in MLH1-associated Lynch syndrome]. / Das Two-in-one-hit-Modell der beschleunigten Genese von kolorektalen Karzinomen beim MLH1-assoziierten Lynch-Syndrom.

In a recently published study a new genetic hypothesis was established that explained the existence of CTNNB1 mutations in Lynch syndrome-associated colorectal carcinomas (MLH1-LS-CRC). This hypothesis states that a mitotic recombination on chromosome 3p simultaneously leads to inactivation of the mismatch repair gene MLH1 and to the activation of CTNNB1. This explains the increased frequency of CTNNB1 mutations in MLH1-LS-CRC compared with other colon carcinomas. To test this hypothesis, various experiments were carried out that show that the first phase of recombination occurs in non-cancerous tissues, which favours the development of CTNNB1 mutations. This mechanism could explain the rapid tumour progression in MLH1-LS-CRC. The results highlight the importance of mitotic recombination in carcinogenesis and provide an insight into the genetic basis of colorectal carcinoma in the context of Lynch syndrome.

[Gastrointestinal polyposis syndromes]. / Gastrointestinale Polyposissyndrome.

BACKGROUND: Gastrointestinal polyposis syndromes are the second most common cause of hereditary colorectal carcinomas after Lynch syndrome (hereditary non-polyposis colon cancer, HNPCC). The detection of a causal germline mutation in an affected family member serves for differential diagnosis, assessment of the recurrence risk and predictive testing of healthy individuals at risk. OBJECTIVES: The present article aims to provide an overview of the differential diagnosis of different gastrointestinal polyposis syndromes based on the endoscopic findings, polyp histology, extraintestinal phenotype and molecular genetic diagnostics. MATERIALS AND METHODS: The present article is based on a literature search on gastrointestinal polyposis syndromes. RESULTS: In addition to familial adenomatous polyposis (FAP), there are further subtypes of adenomatous polyposis that can often only be distinguished by the detection of a causative germline mutation and are sometimes associated with different extracolonic manifestations. In hamartomatous polyposis syndromes, the clinical overlaps often cause differential diagnostic problems. Serratated polyposis syndrome is possibly the most frequent polyposis syndrome, although its cause is currently largely unexplained. CONCLUSIONS: Early detection and correct classification of polyposis is crucial for adequate prevention and therapy. Access to multidisciplinary expert centres is useful for the care of families.

Dye chromoendoscopy leads to a higher adenoma detection in the duodenum and stomach in patients with familial adenomatous polyposis.

Backround and study aims Duodenal cancer is the cancer most often seen in patients with familial adenomatous polyposis (FAP) who have undergone risk-reducing colonic surgery. Almost all patients with FAP eventually develop duodenal adenomas and risk for duodenal cancer is up to 12 % with poor prognosis. In addition, there is a rising concern regarding increased gastric cancer risk in patients with FAP. Our aim was to enhance polyp detection by using CE (CE) with the application of indigo carmine dye. Patient and methods We conducted a prospective, blinded study of patients with FAP undergoing endoscopic examination of the upper gastrointestinal tract. First, a standard white-light examination (WLE) was done followed by an examination performed by an endoscopist who was blinded to the previous examination, using chromoendoscopy (CE) (0.4 % indigo carmine dye). Results Fifty patients were included in the study. Using WLE, a median number of 13 adenomas (range 0-90) was detected compared to 23 adenomas/patient (range 0-150; P  < 0.0001) detected after staining, leading to a higher Spigelman stage in 16 patients (32 %; P  = 0.0003). CE detected significantly more larger adenomas (> 10 mm) than WLE (12 vs. 19; P  = 0.0391). In the gastric antral region, a median number of 0 adenomas (range 0-6) before and 0.5 adenomas (range 0-7) after staining ( P  = 0.0025) were detected. Conclusion This prospective endoscopic trial, to our knowledge the largest in patients with FAP, showed a significant impact of CE on adenoma detection and therapeutic management in the upper gastrointestinal tract. This leads to more intensive surveillance intervals.

Feasibility and safety of long-term photodynamic therapy (PDT) in the palliative treatment of patients with hilar cholangiocarcinoma.

BACKGROUND AND AIM: PDT is an important palliative option for patients with unresectable extrahepatic cholangiocarcinoma (CC). However, the results published to date reported on studies with no more than 6 (mostly up to 4) PDT procedures. Furthermore, the clinical experience of PDT in combination with chemotherapy is limited. The purpose of this retrospective analysis was to evaluate the feasibility and safety of multiple (4 to 14) settings of PDT, combined with biliary drainage, and (in some cases) with chemotherapy. - METHODS: Ten patients with unresectable extrahepatic CC were treated with biliary stenting and at least 4 PDT procedures in our department between 10/2005 and 08/2010. - RESULTS: Ten patients (male/female = 5/5), mean age 68.8 years (range, 54 - 81 years) who received at least 4 PDT procedures were analyzed. All patients underwent endoscopic biliary drainage. Nine patients received metallic stents and one patient a plastic stent. In 4 patients (40%) bilateral metal stenting (JoStent SelfX®) was performed. The mean number of PDT sessions was 7.9 ± 3.9 (range: 4 - 14). Eight patients had elevated bilirubin levels with a mean bilirubin at admission of 9.9 ± 11.3 mg/dL, which had decreased to an average minimum of 1.2 ± 0.9 mg/dL after 3 months. No severe toxicity was noted. Two patients received concomitant chemotherapy (GEMCIS as 1st line, GEMOX plus cetuximab as 2nd line). The median overall survival has not been reached, whereas the estimated survival of all patients was 47.6 months, 95% CI 25.9 - 48.1. - CONCLUSION: Long-term PDT in patients with extrahepatic CC is feasible and effective and is accompanied - at least in this cohort- by a survival time of more than 2 years.

Chromocolonoscopy detects more adenomas than white light colonoscopy or narrow band imaging colonoscopy in hereditary nonpolyposis colorectal cancer screening.

BACKGROUND AND STUDY AIMS: Individuals carrying germline mutations in one of the genes responsible for hereditary nonpolyposis colon cancer (HNPCC) have a lifetime risk of up to 80 % of developing colorectal cancer. As there is evidence for a higher incidence of flat adenomatous precursors and because an accelerated adenoma-carcinoma sequence has been postulated for these patients, early detection of these lesions is essential. It was the aim of the present study to assess the detection rate of polypoid lesions by comparing chromocolonoscopy with standard white light colonoscopy and narrow-band imaging (NBI) colonoscopy. PATIENTS AND METHODS: 109 patients were included (98 with a functionally relevant mutation in a mismatch repair gene, 11 fulfilling the strict Amsterdam criteria). In 47 patients, standard colonoscopy was followed by chromocolonoscopy with indigo carmine. In 62 patients, NBI was performed first followed by chromocolonoscopy. RESULTS: A total of 128 hyperplastic and 52 adenomatous lesions were detected. In the first series, 0.5 lesions/patient were identified by standard colonoscopy and 1.5 lesions/patient by chromocolonoscopy ( P < 0.001). In the second series, 0.7 lesions/patient were detected by NBI colonoscopy and 1.8 lesions/patient by chromocolonoscopy ( P = 0.01). At least one adenoma was detected in 15 % of patients by both standard and NBI colonoscopy compared with 28 % of patients by chromocolonoscopy. CONCLUSION: According to this study, chromocolonoscopy detects significantly more hyperplastic and, in particular, adenomatous lesions than standard white light colonoscopy or NBI.