3' Mutation of the APC gene and family history of FAP in a patient with apparently sporadic desmoid tumors

Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines 2020 for the Clinical Practice of Hereditary Colorectal Cancer

Hereditary colorectal cancer (HCRC) accounts for < 5% of all colorectal cancer cases. Some of the unique characteristics commonly encountered in HCRC cases include early age of onset, synchronous/metachronous cancer occurrence, and multiple cancers in other organs. These characteristics necessitate different management approaches, including diagnosis, treatment or surveillance, from sporadic colorectal cancer management. There are two representative HCRC, named familial adenomatous polyposis and Lynch syndrome. Other than these two HCRC syndromes, related disorders have also been reported. Several guidelines for hereditary disorders have already been published worldwide. In Japan, the first guideline for HCRC was prepared by the Japanese Society for Cancer of the Colon and Rectum (JSCCR), published in 2012 and revised in 2016. This revised version of the guideline was immediately translated into English and published in 2017. Since then, several new findings and novel disease concepts related to HCRC have been discovered. The currently diagnosed HCRC rate in daily clinical practice is relatively low; however, this is predicted to increase in the era of cancer genomic medicine, with the advancement of cancer multi-gene panel testing or whole genome testing, among others. Under these circumstances, the JSCCR guidelines 2020 for HCRC were prepared by consensus among members of the JSCCR HCRC Guideline Committee, based on a careful review of the evidence retrieved from literature searches, and considering the medical health insurance system and actual clinical practice settings in Japan. Herein, we present the English version of the JSCCR guidelines 2020 for HCRC.

APC mosaicism in a young woman with desmoid type fibromatosis and familial adenomatous polyposis

Familial adenomatous polyposis (FAP) is usually caused by germline mutations in the adenomatous polyposis coli (APC) gene. The classic form is characterized by hundreds to thousands of adenomas in the colorectum and early onset colorectal cancer (CRC) if left untreated. FAP is also associated with multiple extra-colonic manifestations such as gastroduodenal polyps, osteomas, epidermoid cysts, fibromas and desmoids. Most desmoid tumours in FAP patients occur intra-abdominally. Approximately 15–20% of the APC mutations are de novo mutations. Somatic mosaicism has been reported in some sporadic cases of polyposis but is probably an underestimated cause of the disease. This case report presents the detection of a mosaic APC mutation in a 26-year-old woman who as a child had been diagnosed with desmoid type fibromatosis. FAP was suggested when she presented with extensive extra abdominal fibromatosis. Our findings indicate that APC mutations may be suspected in patients presenting with a desmoid regardless of its location. If there is clinical evidence that the patient has FAP, adenomas and colonic mucosa in addition to leukocyte DNA should be included in the screening, preferably using methods that are more sensitive than Sanger sequencing.

Japanese Society for Cancer of the Colon and Rectum (JSCCR) Guidelines 2016 for the Clinical Practice of Hereditary Colorectal Cancer (Translated Version)

Hereditary colorectal cancer accounts for less than 5% of all colorectal cancer cases. Some of the unique characteristics that are commonly encountered in cases of hereditary colorectal cancer include early age at onset, synchronous/metachronous occurrence of the cancer, and association with multiple cancers in other organs, necessitating different management from sporadic colorectal cancer. While the diagnosis of familial adenomatous polyposis might be easy because usually 100 or more adenomas that develop in the colonic mucosa are in this condition, Lynch syndrome, which is the most commonly associated disease with hereditary colorectal cancer, is often missed in daily medical practice because of its relatively poorly defined clinical characteristics. In addition, the disease concept and diagnostic criteria for Lynch syndrome, which was once called hereditary non-polyposis colorectal cancer, have changed over time with continual research, thereby possibly creating confusion in clinical practice. Under these circumstances, the JSCCR Guideline Committee has developed the "JSCCR Guidelines 2016 for the Clinical Practice of Hereditary Colorectal Cancer (HCRC)," to allow delivery of appropriate medical care in daily practice to patients with familial adenomatous polyposis, Lynch syndrome, or other related diseases. The JSCCR Guidelines 2016 for HCRC were prepared by consensus reached among members of the JSCCR Guideline Committee, based on a careful review of the evidence retrieved from literature searches, and considering the medical health insurance system and actual clinical practice settings in Japan. Herein, we present the English version of the JSCCR Guidelines 2016 for HCRC.

Risk Factors for the Development of Desmoid Tumor After Colectomy in Patients with Familial Adenomatous Polyposis: Multicenter Retrospective Cohort Study in Japan

BACKGROUND

Desmoid tumor (DT) is the primary cause of death in patients with familial adenomatous polyposis (FAP) after restorative proctocolectomy. This study aimed to identify risk factors for DT in a Japanese population.

METHODS

Clinical data for 319 patients with FAP undergoing first colectomy from 2000 to 2012 were reviewed retrospectively.

RESULTS

Two hundred seventy-seven FAP patients were included in this study. Thirty-nine (14.1 %) patients developed DT. Occurrence sites were the intraperitoneal region in 25 (64.1 %) cases, intraperitoneal region and abdominal wall in three (7.7 %), and abdominal wall in nine (23.1 %). The mean period from surgery to DT development was 26.3 months (range 4-120 months). Gender (female vs. male, p = 0.03), age at surgery (>30 vs. ≤30 years, p = 0.02), purpose of surgery (prophylactic vs. cancer excision, p = 0.01), and surgical procedure (proctocolectomy [ileoanal anastomosis (IAA), ileoanal canal anastomosis (IACA), total proctocolectomy (TPC)] vs. total colectomy [ileorectal anastomosis, partial colectomy]; p = 0.03) significantly influenced the estimated cumulative risk of developing DT at 5 years after surgery. Conversely, approach (laparoscopic vs. open, p = 0.17) had no significant effect on the increased risk of DT occurrence. In multivariate analysis, female gender, with a hazard ratio of 2.2 (p = 0.02,) and proctocolectomy (IAA, IACA, TPC), with a hazard ratio of 2.2 (p = 0.03), were independent risk factors for DT incidence after colectomy.

CONCLUSIONS

Female gender and proctocolectomy (IAA, IACA, TPC) were independent risk factors for developing DT after colectomy in patients with FAP.

Desmoid tumor patients carry an elevated risk of familial adenomatous polyposis

BACKGROUND

The prevalence of desmoid tumors among patients with familial adenomatous polyposis (FAP) is at least 10%, and the prevalence of FAP among desmoid patients varies between 7.5-16%.

METHODS

Data included 106 desmoid patients identified from the database of the Department of Pathology, Helsinki University Hospital, years 2000-2012. We evaluated the risk of FAP among patients by using endoscopy and we identified individuals with attenuated FAP by APC gene mutation test. We compared sporadic desmoid patients' and FAP patients' clinical characteristics.

RESULTS

Ten of 106 patients already had FAP diagnosis before the desmoid. Eleven patients had had FAP screening already earlier due to desmoid and three of them were found to have FAP. Total of 52 patients participated into prospective screening of FAP. No new cases of FAP were found. The risk of FAP among desmoid tumor patients was 4.8%. In the FAP desmoid group, there were more males and patients were younger than in the sporadic group. Intra-abdominal desmoids were more common in the FAP group.

CONCLUSIONS

Patients with desmoid carry an elevated risk of FAP and therefore screening is indicated. Asymptomatic patients with desmoid situated in extra truncal region may not need to be screened.

Does intra-abdominal desmoid disease affect patients with an ileal pouch differently than those with an ileorectal anastomosis?

BACKGROUND

Nobody has analyzed the sequelae of desmoids according to the type of surgery that precipitated them.

OBJECTIVE

This study aims to determine whether the clinical effects of abdominal desmoids would be worse in patients with restorative proctocolectomy than in patients with ileorectal anastomosis.

DESIGN

This is a retrospective, database study.

PATIENTS

Included were patients with familial adenomatous polyposis who had undergone proctocolectomy with IPAA or colectomy and ileorectal anastomosis, and subsequently developed an intra-abdominal desmoid tumor.

MAIN OUTCOME MEASURES

The primary outcome measures were the clinical course of the desmoids; morbidity, and the requirement for stoma.

RESULTS

There were 86 patients: 49 had restorative proctocolectomy and 37 had ileorectal anastomosis. Patient demographics were similar. Average follow-up was 9.8 years (range, 2.7-23.8) and 16.3 years (range, 2.3 - 42.9). Treatment of the desmoids included surgery (64.4% vs 65.6%), medical therapy (69.4% vs 59.5%), chemotherapy (36.2% vs 30.0%), and radiotherapy (4.5% vs 10.0%), and was the same for each group. The overall complication rate of desmoids was similar, approaching 70%. The risk of individual complications was also similar (bleeding (2.0% vs 0.0%), fistula (10.2% vs 13.5%), bowel obstruction (32.7% vs 48.6%), pain (34.7% vs 21.6%), and death related to desmoid tumors (2.0% vs 10.8%)); 38.8% of the restorative proctocolectomy group and 51.4% the ileorectal group had surgery for desmoid tumor complications (P = .21), and 22.4% and 22.2% of patients ultimately had permanent stomas.

LIMITATIONS

This study was limited by the relatively small numbers of patients.

CONCLUSION

The morbidity associated with desmoid tumors has not been shown to differ, whether they arise after restorative proctocolectomy or ileorectal anastomosis.

Surgical prophylaxis in familial adenomatous polyposis: do pre-existing desmoids outside the abdominal cavity matter?

Desmoid tumours (DT) are myofibroblastic proliferations found in 10-25% of familial adenomatous polyposis (FAP) patients, either intra-abdominally (IA), in the abdominal wall (AW) or elsewhere (extra-abdominal (EA)). Most DT occur following prophylactic colectomy but occasionally patients present with pre-operative DT. Mutations 3' to codon 1444, predispose to DT and attenuated phenotype, leading to a potential strategy of delaying surgery in patients at high risk of DT. Here we assess if the existence of a pre-operative AW-DT or EA-DT predisposes to IA-DT following laparotomy. Data were collected on FAP patients undergoing primary surgery at St Mark's Hospital. Patients were stratified into those having no DT, EA-DT or AW-DT pre-operatively. Relative-risks were calculated and proportions compared using Fisher's exact-test. 587 FAP patients were identified; nine discovered with IA-DT intra-operatively were excluded. 5(0.9%) and 6(1%) of the remainder had a pre-operative EA-DT and AW-DT, respectively; one (0.2%) had both. Six of these 12 developed a post-operative IA-DT. 566(98%) had no pre-operative DT, 50(9%) of these developed IA-DT post-operatively; median time to tumour was 2 (IQR, 1-3.5) years. A pre-operative AW-DT predisposed to IA-DT post-operatively (RR = 7.6, 95% CI 4.0-14.1, P = 0.0009) whilst EA-DT did not (RR = 2.3, 0.4-13.3, P = 0.38). A 3' mutation was significantly associated with post-operative IA-DT in the 'no pre-operative DT' group (P = 0.002). The presence of a DT external to the abdominal cavity pre-operatively, poses a clinical challenge with regards to surgical decision-making. Patients with an AW-DT pre-operatively may warrant a conservative surgical approach, to minimize post-operative IA-DT risk.

A nation-wide study comparing sporadic and familial adenomatous polyposis-related desmoid-type fibromatoses

Desmoid-type fibromatoses are neoplasms of fibroblastic origin, occurring sporadically or associated with familial adenomatous polyposis (FAP) coli. By comparing sporadic and FAP-associated desmoid-type fibromatoses, we tried to identify clinical characteristics, which may indicate FAP. Histopathology data of all Dutch patients with desmoid-type fibromatoses diagnosed between 1999 and 2009 were retrieved from PALGA, the nation-wide network and registry of histopathology in the Netherlands. For calculation of incidence rates, person-years from the general matched population were used. Based on polyp counts in pathological records, the cohort was divided into a FAP group and a non-FAP group. Patient- and tumor characteristics were compared between the two groups. A total number of 519 patients older than 10 years with a confirmed diagnosis of desmoid-type fibromatoses were included. Thirty-nine (7.5%) desmoid patients were documented of having FAP. The incidences of sporadic and FAP-related desmoid-type fibromatoses were 3.42 and 2,784 per million person-years, respectively. The majority of FAP patients developed desmoid-type fibromatoses after the diagnosis of FAP. Having FAP was associated with male gender [odds ratio (OR) 2.0, p = 0.034], desmoid diagnosis at an earlier age (mean 36 vs. 42 years, p = 0.031), and desmoid localization intra-abdominally (OR 18.9, p ≤ 0.001) or in the abdominal wall (OR 4.8, p ≤ 0.001), compared to extra-abdominal desmoid localization. In conclusion, patients with desmoid-type fibromatoses are at risk of underlying FAP. Especially cases with desmoid localization intra-abdominal or in the abdominal wall, and all patients younger than 60 years, have a substantial increased risk and should be referred for colonoscopy.

Polishing the crystal ball: knowing genotype improves ability to predict desmoid disease in patients with familial adenomatous polyposis

INTRODUCTION

Desmoid disease occurs in one third of patients with familial adenomatous polyposis. Patients may be protected by changing surgical strategy. We designed a formula to predict desmoid risk and tested the value of adding genotype to the formula.

METHODS

A desmoid risk factor was calculated by summing points awarded for gender (male = 1, female = 3), extracolonic manifestations (nil = 1, one = 2, >one = 3), and family history of desmoids (negative = 1, one relative = 2, more than one relative = 3). Performance of the score with and without genotype (5' 1309 = 1, 1309-1900 = 2, 3' 1900 = 3) was analyzed.

RESULTS

There were 839 patients (138 desmoids) without genotype and 154 (30 desmoids) with genotype. The mean desmoid risk factor score of patients without desmoids (no genotype) was 4.7 (+/-1.4 SD) and for patients with desmoid the desmoid risk factor was 6.0 (+/-1.7, P < 0.001). Corresponding data for patients with genotype was 6.1 +/- 1.3 (no desmoids) and 8.4 +/- 1.8 with desmoids (P < 0.001). Of patients without genotype, 648 patients were at low risk and 9.9% had desmoid disease, 178 patients were at medium risk and 34% had desmoids, and 10 patients were at high risk and all had desmoids. Of those with genotype information, 83 patients were at low risk and 5% had desmoids, 52 patients were at medium risk and 21% had desmoids, and 18 patients were at high risk and 83% had desmoids.

CONCLUSION

The desmoid risk factor identifies patients with various levels of risk for developing desmoid disease, and can be used to plan surgical strategies designed to minimize desmoid risk.

The role of APC and beta-catenin in the aetiology of aggressive fibromatosis (desmoid tumors)

BACKGROUND

Aggressive fibromatosis (syn. desmoid tumor) is a sporadically occurring neoplastic proliferation of fibroblasts originating from musculoaponeurotic planes, forming invasively growing masses without the capability to metastasize. The choice of treatment remains surgical resection with or without radiotherapy, and is characterized by high recurrence rates. Better understanding of the aetiology of aggressive fibromatosis is needed to be able to develop new treatment strategies to cope with the high recurrence rates.

METHODS

Relevant studies were identified through a search of the electronic databases PubMed/ Medline. The following search terms were used: 'aggressive fibromatosis', 'desmoid tumor', 'adenomatous polyposis coli', 'APC', 'beta-catenin', 'Wnt', 'Wingless' and 'Wnt/Wingless'. Studies were selected for review on the basis of abstract reading. A hand search was performed by checking reference lists in selected articles.

RESULTS

The neoplastic nature of aggressive fibromatosis and the role of the adenomatous polyposis coli (APC) and beta-catenin signaling cascade in driving the onset and progression of this disease are discussed.

CONCLUSION

Mutations in either the APC or beta-catenin genes are likely to be a major driving force in the formation of these desmoid tumors. More research is needed to develop new treatment strategies.