Potential risks associated with the use of ionizing radiation for imaging and treatment of colorectal cancer in Lynch syndrome patients.

The aim of this review is to investigate the literature pertaining to the potential risks of low-dose ionizing radiation to Lynch syndrome patients by use of computed tomography (CT), either diagnostic CT colonography (CTC), standard staging CT or CT surveillance. Furthermore, this review explores the potential risks of using radiotherapy for treatment of rectal cancer in these patients. No data or longitudinal observational studies of the impact of radiation exposure on humans with Lynch syndrome were identified. Limited experimental studies utilizing cell lines and primary cells exposed to both low and high radiation doses have been carried out to help determine radio-sensitivity associated with DNA mismatch repair gene deficiency, the defining feature of Lynch syndrome. On balance, these studies suggest that mismatch repair deficient cells may be relatively radio-resistant (particularly for low dose rate exposures) with higher mutation rates, albeit no firm conclusions can be drawn. Mouse model studies, though, showed an increased risk of developing colorectal tumors in mismatch repair deficient mice exposed to radiation doses around 2 Gy. With appropriate ethical approval, further studies investigating radiation risks associated with CT imaging and radiotherapy relevant doses using cells/tissues derived from confirmed Lynch patients or genetically modified animal models are urgently required for future clinical guidance.

FDG PET/CT in a Case of Lynch Syndrome With Synchronous Inverted Urothelial Papilloma of the Bladder, Urothelial Carcinoma of the Ureter, and Jejunal Adenocarcinoma.

ABSTRACT: A 64-year-old man was referred because of the right ureteral obstruction. CT urography showed an intraluminal enhancing mass in the right midureter and an enhancing nodule in the bladder wall. FDG PET/CT showed increased FDG uptake of the ureteral mass and an unexpected hypermetabolic lesion in the jejunum. The patient underwent transurethral resection of the bladder tumor, right laparoscopic nephroureterectomy, and partial enterectomy. Inverted urothelial papilloma of the bladder, high-grade urothelial carcinoma of the right ureter, and jejunal adenocarcinoma were confirmed by histopathology. Genetic testing of the jejunal adenocarcinoma revealed MSH2 germline mutation, confirming the diagnosis of Lynch syndrome.

Linked Colour imaging for the detection of polyps in patients with Lynch syndrome: a multicentre, parallel randomised controlled trial.

OBJECTIVE: Despite regular colonoscopy surveillance, colorectal cancers still occur in patients with Lynch syndrome. Thus, detection of all relevant precancerous lesions remains very important. The present study investigates Linked Colour imaging (LCI), an image-enhancing technique, as compared with high-definition white light endoscopy (HD-WLE) for the detection of polyps in this patient group. DESIGN: This prospective, randomised controlled trial was performed by 22 experienced endoscopists from eight centres in six countries. Consecutive Lynch syndrome patients ≥18 years undergoing surveillance colonoscopy were randomised (1:1) and stratified by centre for inspection with either LCI or HD-WLE. Primary outcome was the polyp detection rate (PDR). RESULTS: Between January 2018 and March 2020, 357 patients were randomised and 332 patients analysed (160 LCI, 172 HD-WLE; 6 excluded due to incomplete colonoscopies and 19 due to insufficient bowel cleanliness). No significant difference was observed in PDR with LCI (44.4%; 95% CI 36.5% to 52.4%) compared with HD-WLE (36.0%; 95% CI 28.9% to 43.7%) (p=0.12). Of the secondary outcome parameters, more adenomas were found on a patient (adenoma detection rate 36.3%; vs 25.6%; p=0.04) and a colonoscopy basis (mean adenomas per colonoscopy 0.65 vs 0.42; p=0.04). The median withdrawal time was not statistically different between LCI and HD-WLE (12 vs 11 min; p=0.16). CONCLUSION: LCI did not improve the PDR compared with HD-WLE in patients with Lynch syndrome undergoing surveillance. The relevance of findings more adenomas by LCI has to be examined further. TRIAL REGISTRATION NUMBER: NCT03344289.

Malignant potential of colorectal neoplasms in Lynch syndrome: an analysis of 325 lesions endoscopically treated at a single institute.

BACKGROUND: Patients with Lynch syndrome are at an increased risk of developing colorectal cancer, and the adenoma-carcinoma sequence is accelerated in these patients. However, the clinicopathological characteristics of colorectal neoplasms in Lynch syndrome patients are not well-known. METHODS: A total of 325 consecutive colorectal neoplasms were endoscopically removed from 68 patients with Lynch syndrome between June 2005 and May 2018 and retrospectively reviewed. RESULTS: Of the 325 lesions, 94 (29%), 220 (68%) and 11 (3%) were from patients with MLH1, MSH2 and MSH6 mutations, respectively. The median lesion size was 5 mm (range 2-40 mm), with 229 (71%) lesions having a non-polypoid morphology. The frequencies of advanced neoplasms, including high-grade adenomas, intramucosal carcinomas and submucosal invasive carcinomas were 14, 34, 97 and 93% for lesions with diameters of <5, ≥5 and <10, ≥10 and <20, and ≥20 mm, respectively. The frequencies of advanced neoplasms in the proximal colon, distal colon and rectum did not significantly differ (36, 35 and 41%, respectively). CONCLUSIONS: Our results suggest that the malignant transformation interval from low-grade adenomas to advanced neoplasms is similar in all parts of the colon. Furthermore, since one-third of neoplastic lesions with diameters of ≥5 and <10 mm and most of those ≥10 mm were advanced neoplasms, we recommend that in Lynch syndrome patients, careful colonoscopic surveillance should be performed throughout the colon, and all neoplastic lesions, regardless of the size, should be subjected to detailed endoscopic examination, complete resection and detailed pathological examination.

Lynch syndrome-associated repeated stroke with MLH1 frame-shift mutation.

Lynch syndrome (LS) is an autosomal dominant inherited disease caused by germline mutations in DNA mismatch repair (MMR) genes, including MLH1, MSH2, MSH6, and PMS2, which predisposes patients to various malignant neoplasms. Previous studies showed that MLH1, MSH2, MSH6, and PMS2 mutation in LS were associated with an elevated risk of colorectal, gastric, endometria, ovarian, and other cancers among family members. Patients of these kinds of cancers had high incidence of synchronous and metasynchronus. We describe the case of a 34-year-old female patient with 50 days of sudden dizziness and left limb weakness, whose head CT scan showed large infarction in the right frontal temporal parietal lobe and basal ganglia area. Imaging examinations and pathological biopsy indicated high-grade serous carcinoma (HGSC) IIIA1 of the right ovary. In addition, a novel frame-shift mutation in the MLH1 gene (c.1621dupG, p.A541Gfs*16) was found in the genetic panel sequence. It may render declining of MLH1 protein and also associate with the patient's progressive clinical manifestations of multiple systems. Therefore, the timely use of prenatal diagnosis to prevent unnecessary new cases of this severe genetic disease is available.

Hereditary ovarian tumour syndromes: current update on genetics and imaging.

Hereditary ovarian tumour syndromes are a diverse group of hereditary syndromes characterised by the development of specific histotypes of ovarian neoplasms. While BRCA syndromes are exclusively associated with high-grade serous carcinomas, patients with Lynch syndrome show a preponderance of endometrioid subtype of ovarian and endometrial carcinomas. Distinct non-epithelial phenotypes, such as sex cord stromal tumours with annular tubules, Sertoli-Leydig cell tumours, and small cell carcinoma of the hypercalcaemic type occur in patients with Peutz-Jeghers, DICER1, and rhabdoid tumour predisposition syndromes, respectively. Gorlin-Goltz syndrome is characterised by the development of bilateral, multiple ovarian fibromas in 14-24% of patients. Ovarian steroid cell tumours and broad ligament papillary cystadenomas are characteristically found in women with von Hippel-Lindau syndrome. Recent studies have allowed the characterisation of tumour genetics and associated oncological pathways that contribute to tumourigenesis. Implications of the diagnosis of these syndromes on screening, management, and prognosis are discussed.

Upper Endoscopic Surveillance in Lynch Syndrome Detects Gastric and Duodenal Adenocarcinomas.

Lynch syndrome is a prevalent hereditary cancer predisposition syndrome. While colorectal cancer is the most common gastrointestinal (GI) cancer in Lynch syndrome, there is also increased risk of gastric and small intestinal cancers. Recommendations for upper GI cancer surveillance in Lynch syndrome vary widely with limited data supporting effectiveness. Herein, we collected data on individuals with a diagnosis of Lynch syndrome seen at our tertiary care referral center. We identified individuals who underwent upper endoscopy and those with upper GI cancers, and associated demographics, genetic testing results, and endoscopic information. Standard statistical analyses were performed. Among 295 individuals with Lynch syndrome seen at our center, 217 (73.6%) underwent 660 total upper endoscopies. Of these 217, precancerous upper endoscopy findings included Barrett's esophagus (7, 3.2%), gastric intestinal metaplasia (18, 8.3%), and duodenal adenomas (4, 1.8%), and Helicobacter pylori was identified in 6 (2.8%). Upper GI cancers were diagnosed in 11 individuals (3.7%), including esophageal in 1, gastric in 6, and duodenal in 4. Five (1.7%) of these upper GI cancers were identified on surveillance. Individuals with upper GI cancers identified on surveillance were older at first surveillance endoscopy, with median age 63.3 versus 44.9 years (P < 0.001). Of the upper GI cancers detected on surveillance, 80% (4/5) occurred within 2 years of last upper endoscopy and 80% were stage I. In conclusion, upper endoscopy surveillance in Lynch syndrome identifies upper GI cancers. For individuals with Lynch syndrome who undergo upper GI surveillance, a short surveillance interval may be warranted.

Coexistent Dedifferentiated Endometrioid Carcinoma of the Uterus and Adenocarcinoma of the Bladder in Lynch Syndrome: Case Report and Review of the Literature.

Lynch syndrome is an autosomal dominant disorder, caused by an abnormality in DNA mismatch repair genes and characterized by the development of a variety of cancers. Upper urinary tract urothelial carcinoma is well characterized in Lynch syndrome; however, support for the inclusion of bladder urothelial carcinoma is limited, except for MSH2 mutation carriers. Urologic adenocarcinoma has not been documented in Lynch syndrome. Here we report, to the best of our knowledge, the first case of bladder adenocarcinoma, synchronous with uterine endometrioid dedifferentiated endometrioid adenocarcinoma in a patient with Lynch syndrome. We present a 47-year-old woman with an MLH1 gene mutation (G133X 397G>T) who presented with menorrhagia. Eleven family members have this mutation, 6 with carcinoma: 5 colorectal and 1 with a gynecologic primary of unknown type. Colonoscopy and endoscopy were unremarkable. Positron emission and computed tomography revealed a 3 cm anterior dome bladder mass without additional extrauterine disease or uterine connection. She underwent partial cystectomy, laparoscopic hysterectomy, bilateral salpingo-oophorectomy, and lymphadenectomy. The uterus demonstrated a dedifferentiated endometrioid adenocarcinoma, immunohistochemically positive for vimentin, ER, CK7, MSH2, MSH6, and p53 (focally) and negative for CEA, CDX2, CK20, ß-catenin, MLH1, and PMS2. The bladder demonstrated a well-differentiated, enteric-type adenocarcinoma without muscularis propria invasion, positive for CEA, CDX2, CK20, p53, MSH2, and MSH6 and negative for vimentin, ER, CK7, MLH1, and PMS2. Eleven nodes were negative for carcinoma. The morphologic, immunohistochemical, and clinical findings support synchronous bladder adenocarcinoma, enteric type, and uterine dedifferentiated endometrioid adenocarcinoma, in a patient with Lynch syndrome.

Imaging-based definition of lower uterine segment carcinoma to improve the detection sensitivity of probable Lynch syndrome.

OBJECTIVE: The aim of this study was to investigate a magnetic resonance imaging-based definition of lower uterine segment carcinoma. METHODS: We retrospectively reviewed 587 consecutive patients with endometrial cancer who underwent hysterectomy. Lower uterine segment carcinoma was determined through pathological examination and magnetic resonance imaging assessment. For imaging assessment, the location of the inner lining of the uterus was classified into four equal parts on a sagittal section image. A tumor was defined as lower uterine segment carcinoma when its thickest part was located in the second or the third part from the uterine fundus. Lower uterine segment carcinoma was further divided into lower uterine segment in a narrow sense, upon which diagnosis was exclusively based on pathological findings, and lower uterine segment in a broad sense that were the remaining lower uterine segment carcinomas except lower uterine segment carcinomas in a narrow sense. The relationship between lower uterine segment carcinoma and probable Lynch syndrome was investigated. Patients with loss of MSH2, MSH6, and PMS2 expression or those with tumors with loss of MLH1 and absence of MLH1 promoter methylation were diagnosed as probable Lynch syndrome. RESULTS: Lower uterine segment carcinoma was identified in 59 (10.2%) patients. Twenty-eight (47.5%) patients were categorized as lower uterine segment in a narrow sense and 31 (52.5%) as lower uterine segment in a broad sense. Among them, probable Lynch syndrome was identified in 12 (20.3%) cases. There was no difference in clinical profiles, including the prevalence of probable Lynch syndrome between the two categories. CONCLUSIONS: A magnetic resonance imaging-based expanded definition of lower uterine segment carcinoma is likely to secure characteristics equivalent to a conventional pathology-based definition of lower uterine segment carcinoma. The novel definition of lower uterine segment carcinoma might improve the detection of probable Lynch syndrome.

Update on the role of chromoendoscopy in colonoscopic surveillance of patients with Lynch syndrome.

(Virtual) chromoendoscopy (CE) improves the detection of small or flat colorectal polyps; however, the evidence in high-risk groups, such as patients of Lynch syndrome (LS), is low. Our aim was to identify and update the evidence for the recommendations regarding surveillance of LS patients, for which the current underlying evidence for use of (virtual) CE was explored. A systematic literature search in PubMed, EMBASE, and Cochrane library was conducted, for all studies comparing (virtual) CE with white-light endoscopy in LS patients. Studies are explained in detail, with special attention to study design, type of (virtual) CE, and timing of polypectomy. Eight studies (409 patients) were included. Five were nonrandomized back-to-back studies and three were randomized back-to-back studies (one parallel and two cross-over design). In six studies the polyps were directly removed, while in two studies polyps were removed only during the second caecal withdrawal. Five studies researched CE with indigo carmine and three studies investigated virtual CE. Due to the heterogeneity between studies, no statistical analysis could be performed. There was a large variety in study design, timing of polypectomy, different (virtual) CE techniques and the patients that were included. Based on current literature, no firm conclusions can be drawn with respect to the additional value of (virtual) CE in the surveillance of patients with LS. However, training of endoscopists in detection and removal of nonpolypoid colorectal neoplasms is crucial, as well as stricter adherence to LS surveillance guidelines in daily clinical practice. For future research, standardization in study designs is needed.

Lynch Syndrome: Genomics Update and Imaging Review.

Lynch syndrome is the most common hereditary cancer syndrome, the most common cause of heritable colorectal cancer, and the only known heritable cause of endometrial cancer. Other cancers associated with Lynch syndrome include cancers of the ovary, stomach, urothelial tract, and small bowel, and less frequently, cancers of the brain, biliary tract, pancreas, and prostate. The oncogenic tendency of Lynch syndrome stems from a set of genomic alterations of mismatch repair proteins. Defunct mismatch repair proteins cause unusually high instability of regions of the genome called microsatellites. Over time, the accumulation of mutations in microsatellites and elsewhere in the genome can affect the production of important cellular proteins, spurring tumorigenesis. Universal testing of colorectal tumors for microsatellite instability (MSI) is now recommended to (a) prevent cases of Lynch syndrome being missed owing to the use of clinical criteria alone, (b) reduce morbidity and mortality among the relatives of affected individuals, and (c) guide management decisions. Organ-specific cancer risks and associated screening paradigms vary according to the sex of the affected individual and the type of germline DNA alteration causing the MSI. Furthermore, Lynch syndrome-associated cancers have different pathologic, radiologic, and clinical features compared with their sporadic counterparts. Most notably, Lynch syndrome-associated tumors tend to be more indolent than non-Lynch syndrome-associated neoplasms and thus may respond differently to traditional chemotherapy regimens. The high MSI in cases of colorectal cancer reflects a difference in the biologic features of the tumor, possibly with a unique susceptibility to immunotherapy. ©RSNA, 2018.

Imaging findings of hereditary renal tumors, a review of what the radiologist should know.

It is estimated that up to 8% of currently diagnosed renal cancers are part of a hereditary syndrome. The radiologist may be the first person to associate a renal tumor presenting during an imaging study to other manifestations of a hereditary syndrome. This diagnosis can have broad implications for the patient but also for other family members. This update reviews the current known associations and emerging mutations of hereditary renal cancers from a radiologist's perspective. Renal manifestations, as well as associated radiological findings and pitfalls are discussed. Additionally, screening and surveillance recommendations are also discussed to aid radiologists in the decision-making process for patient management.

MLH1-rheMac hereditary nonpolyposis colorectal cancer syndrome in rhesus macaques.

Over the past two decades, 33 cases of colonic adenocarcinomas have been diagnosed in rhesus macaques (Macaca mulatta) at the nonhuman primate colony of the Keeling Center for Comparative Medicine and Research at The University of Texas MD Anderson Cancer Center. The distinctive feature in these cases, based on PET/computed tomography (CT) imaging, was the presence of two or three tumor lesions in different locations, including proximal to the ileocecal juncture, proximal to the hepatic flexure, and/or in the sigmoid colon. These colon carcinoma lesions selectively accumulated [18F]fluorodeoxyglucose ([18F]FDG) and [18F]fluoroacetate ([18F]FACE) at high levels, reflecting elevated carbohydrate and fatty acid metabolism in these tumors. In contrast, the accumulation of [18F]fluorothymidine ([18F]FLT) was less significant, reflecting slow proliferative activity in these tumors. The diagnoses of colon carcinomas were confirmed by endoscopy. The expression of MLH1, MSH2, and MSH6 proteins and the degree of microsatellite instability (MSI) was assessed in colon carcinomas. The loss of MLH1 protein expression was observed in all tumors and was associated with a deletion mutation in the MLH1 promoter region and/or multiple single-nucleotide polymorphism (SNP) mutations in the MLH1 gene. All tumors exhibited various degrees of MSI. The pedigree analysis of this rhesus macaque population revealed several clusters of affected animals related to each other over several generations, suggesting an autosomal dominant transmission of susceptibility for colon cancer. The newly discovered hereditary nonpolyposis colorectal cancer syndrome in rhesus macaques, termed MLH1-rheMac, may serve as a model for development of novel approaches to diagnosis and therapy of Lynch syndrome in humans.

Feasibility of Segmental Colectomy Followed by Endoscopic Surveillance as a Treatment Strategy for Colorectal Cancer Patients with Lynch Syndrome.

BACKGROUND: Initial surgical procedures for colorectal cancer (CRC) patients with Lynch syndrome remain controversial. This study assessed the validity of segmental colectomy (SGC) followed by endoscopic surveillance as a treatment strategy for CRC patients with Lynch syndrome. METHODS: Among consecutive patients who underwent surgery for primary CRC between April 1985 and December 2014, 49 patients were observed to have germline mutations in a mismatch repair gene, and 38 patients who underwent SGC followed by periodic endoscopic surveillance at our institution were evaluated for metachronous CRC, need for secondary surgery, and the details of endoscopic surveillance. RESULTS: Of the 38 patients who underwent SGC followed by periodic endoscopic surveillance at our institution, 6 (15.8%) patients showed metachronous CRC, 3 (7.9%) patients underwent endoscopic resection, and the other 3 patients (7.9%) underwent secondary surgery. The dispersion of the endoscopic surveillance interval was significantly greater in patients with metachronous CRC (364 ± 332.9 days) than in those without metachronous CRC (370 ± 129.7 days; p < 0.001). CONCLUSIONS: SGC followed by annual endoscopic surveillance was feasible as a treatment strategy for CRC patients with Lynch syndrome, because the incidence of metachronous CRC and the need for secondary surgery were low. Annual and periodic endoscopic surveillance might be essential for early detection of metachronous CRC and prevention of secondary surgery because of metachronous CRC in CRC patients with Lynch syndrome after SGC.

Metachronous colorectal carcinoma with massive submucosal invasion detected by annual surveillance in a Lynch syndrome patient: a case report.

BACKGROUND: Lynch syndrome is the most common form of hereditary colorectal carcinoma. It is characterized by the presence of germline mutations in DNA mismatch repair genes. Mutation carriers have a lifetime risk of developing colorectal carcinoma of approximately 80%. Current treatment guidelines recommend periodic surveillance for colorectal carcinoma in patients with Lynch syndrome. However, the optimal interval between colonoscopies has not yet been determined. CASE PRESENTATION: We describe a 54-year-old man with Lynch syndrome who was undergoing annual colonoscopy surveillance for the development of colorectal carcinoma. At 54, 57, 59, and 60 years old, a colonoscopy showed high-grade dysplasia and adenoma. Therefore, endoscopic mucosal resection was performed. At 61 years old, a colonoscopy showed metachronous colorectal carcinoma with massive submucosal invasion. He subsequently underwent laparotomy for colorectal carcinoma. CONCLUSIONS: Annual surveillance using colonoscopy can detect colorectal carcinoma at an early stage, leading to reduced mortality. However, some patients might require a laparotomy, as was the case here. More frequent colonoscopic surveillance might be necessary to avoid surgery for colorectal carcinoma in Lynch syndrome patients with multiple risk factors for interval cancer.