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%.
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.
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.
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.
BACKGROUND: The Swedish Polyposis Registry was set up in Sweden in the late 1950s to promote screening of familial adenomatous polyposis (FAP). The aim of this study was to examine the epidemiology of FAP in Sweden, including the influence of screening on morbidity and mortality in colorectal cancer (CRC). METHODS: Four hundred and thirty-one patients (213 males and 218 females) with FAP from 145 families recorded by the Swedish Polyposis Registry were investigated. The effect of screening on morbidity and mortality in CRC was evaluated by comparing the 216 probands with the 215 call-up patients. Three different periods were studied: the pre-screening period (1912-1956), the first screening period (1957-1976), and the second screening period (1977-1996). RESULTS: The mean annual incidence rates during the three periods were 0.2, 1.38, and 0.86 per million, respectively. The birth frequency was calculated to be 1 in 18,000 between 1947 and 1966, and the prevalence was 32 per million at the end of 1996. The proportion of new mutants among the FAP patients born between 1927 and 1966 was estimated to be 11%. The median age at diagnosis of probands was 39 (range, 11-71) years and did not change over time, although an increase was seen in the subgroup with CRC at diagnosis (P = 0.02). In the call-up group the median age at diagnosis was 22 (range, 3-65) years. Sixty-seven per cent of the probands and 3.3% of the call-up patients had CRC at diagnosis, and the corresponding mortality figures were 44% and 1.9%. The risk among probands of having CRC at diagnosis decreased from 81% to 49% (P = 0.0006). Female probands were diagnosed with symptoms (P = 0.03) and CRC (P = 0.04) earlier than male probands. CONCLUSIONS: A nationwide screening program facilitates detection and early diagnosis of FAP. A decrease in CRC morbidity among probands contributed to the improved prognosis. An earlier onset of symptoms and CRC in females indicate that the course of FAP is influenced by sex.
Hereditary nonpolyposis colorectal cancer (HNPCC) and familial adenomatosis polyposis (FAP) are well-known high-risk cancer syndromes. Hereditary colorectal cancer (HCRC) with at least three relatives with colorectal cancer and a dominant pattern of inheritance but with no specifications for age at onset and two close relatives with colorectal cancer (TCR) are other forms of familial clustering known to carry an increased risk of the disease. The frequency of the total burden of familial colorectal cancer is not well known. We therefore investigated the family history of 400/411 (97%) eligible patients with recently diagnosed colorectal cancer in Västmanland county, Sweden, during a 3-year period. Records or death certificates confirmed the diagnoses of relatives. Five patients (1.2%, 95% CI 0.15-2.2) were diagnosed as having HNPCC, eight (1.9%, 95% CI 0.6-3.2) as having HCRC and thirty-four (8.3%, 95% CI 5.6-11.0) were identified as having TCR. In total, 47 patients (11.4%, 95% CI 8.3-14.5) were found to have a contributing familial background. The implication is thus that every ninth patient with colorectal cancer represents a highly or intermediately increased risk of the disease among relatives. We conclude that the low frequency of individuals identified by family history alone makes the establishment of surveillance programs feasible.
Variable endoscopic surveillance protocols and treatment strategies have been proposed for periampullary neoplasia in familial adenomatous polyposis (FAP), primarily because of the lack of long-term, prospective natural history data. A total of 115 patients with FAP were followed prospectively for 10 years with periodic side-viewing upper gastrointestinal endoscopy by a single surgeon. The appearance of the duodenum was classified as stages 1 to 5. Statistical analysis included one-way analysis of variance for age comparisons between stage groupings and Kaplan-Meier analysis for the lifetime risks of having a particular stage of duodenal polyposis. Eighty-seven patients had multiple endoscopies over an average of 6.6 years. Thirty-three subjects had a change in stage, within an average time of 3.9 years at an average age of 41 years. The risk of having stage 3 or 4 duodenal neoplasia increased exponentially after the age of 40. The degree of dysplasia did not correlate with stage at initial classification. Progression of neoplasia in the duodenum of patients with FAP is slow. The severity of duodenal polyposis increases with age and is not influenced by the initial stage. The average time for progression of adenoma to carcinoma is likely long.
Clinical and genetic analysis of 24 Russian patients with attenuated form of family colon adenomatosis was undertaken. On the basis of obtained clinical and genetic data it was defined the algorithm of therapeutic measures in this group of patients--from dynamic monitoring or endoscopic polypectomy to performing extensive resections of the colon in situations associated with cancer development, an increase of the intensity of growth of polyps or an appearance of villous lesions. Some of the patients had molecular-genetics causes of a weakened form of family adenomatosis.