No abstract

The prognosis of rectal cancer (RC) is strictly related to both T and N stage of the disease at the time of diagnosis. RC staging is crucial for choosing the best multimodal therapy: patients with high risk locally advanced RC (LARC) undergo surgery after neoadjuvant chemotherapy and radiotherapy (NAT); those with low risk LARC are operated on after a preoperative short-course radiation therapy; finally, surgery alone is recommended only for early RC. Several imaging methods are used for staging patients with RC: computerized tomography, magnetic resonance imaging, positron emission tomography, and endoscopic ultrasound (EUS). EUS is highly accurate for the loco-regional staging of RC, since it is capable to evaluate precisely the mural infiltration of the tumor (T), especially in early RC. On the other hand, EUS is less accurate in restaging RC after NAT and before surgery. Finally, EUS is indicated for follow-up of patients operated on for RC, where there is a need for the surveillance of the anastomosis. The aim of this review is to highlight the impact of EUS on the management of patients with RC, evaluating its role in both preoperative staging and follow-up of patients after surgery.

Familial adenomatous polyposis (FAP), an autosomal dominantly inherited condition accounting for about 1% of all colorectal cancers, results from mutations in the adenomatous polyposis coli (APC) tumor suppressor gene. The clinical spectrum and severity of FAP varies greatly with the mutation site, and both between and within families. Using the protein truncation test, single strand conformation polymorphism analysis and DNA sequencing, we identified 30 (75%) mutant alleles in 40 unrelated FAP families, for a total of 22 different APC mutations. Of these, 18 are known and 4 are novel: c.1797C>A (C599X), c.893_894delAC, (c.3225T>A; c.3226C>A) and c.4526_4527insT. Of the 30 APC gene mutations, 5 (approximately 17%) are nonsense mutations, 17 (approximately 57%) are small deletions, 5 (approximately 17%) are small insertions and 3 (approximately 10%) are complete deletions. All mutations occurred in single pedigrees, except those at codons 1061 and 1062, each found in two unrelated families, and the mutation at codon 1309 in exon 15, found in five unrelated families. About 40% of mutations, mostly small deletions and insertions, are located at repeated sequences; they promote misalignment-mediated errors in DNA replication and could represent a hot spot mutation region. This study enlarges the spectrum of APC gene mutations and sheds light on the correlation between the site of APC germline mutations and clinical manifestations of FAP.

We evaluated retrospectively the accuracy of endoscopic ultrasonography (EUS) in the preoperative staging of 63 patients with rectal cancer who were hospitalized and underwent surgery at our institution from January 1994 to December 1997. These patients, 39 men and 24 women with a mean age of 60 years, underwent preoperative EUS, which was performed in all cases using an echo-colonoscope Olympus CF UM 20, with a 7.5 MHz radial scanner. Ten patients did not undergo surgery and, therefore, were excluded from the analysis. EUS showed an overall accuracy of 81% for the T stage (including nontraversable stenotic tumors) and of 70% for the N stage. The accuracy of EUS for the T stage increased from 81 to 90% when we excluded those cases with nontraversable stenotic cancers from the analysis. Five tumors (9.4%) were understaged. while another five cases (9.4%) were overstaged. Finally, EUS was highly accurate (81%) in differentiating T1 from T24 tumors. In conclusion, our data shows that EUS is very accurate in the locoregional staging of rectal cancer and confirms the role of this imaging technique in the preoperative staging of patients with rectal cancer.

We describe three unrelated kindreds, affected by familial adenomatous polyposis (FAP), with 5q submicroscopic deletions that encompass the entire adenomatous polyposis coli (APC) gene and the adjacent DP1 gene. In one family the deletion encompasses also the MCC (mutated in colon cancer) gene. Affected members of these families had dysplastic adenomatous polyps and congenital hypertrophy of the retinal pigment epithelium (CHRPE); no individual was affected by mental retardation or facial dysmorphism. The deletions were detected by linkage analysis with several intragenic and closely flanking polymorphic markers and confirmed by a quantitative PCR analysis. This procedure could have an impact on the detection of the molecular defect in FAP patients in whom mutational analysis fails to identify the specific mutation.