Balance between endoscopic and genetic information in the choice of ileorectal anastomosis for familial adenomatous polyposis

Endoscopic management of patients with familial adenomatous polyposis after prophylactic colectomy or restorative proctocolectomy - systematic review of the literature

BACKGROUND

Patients with familial adenomatous polyposis (FAP) develop early colorectal adenomas and if left untreated, progression to cancer is an inevitable event. Prophylactic surgery does not prevent further development of cancer in the rectal remnant, rectal cuff in patients with ileal pouch anal anastomosis (IPAA) and even on the ileal mucosa of the pouch body. The aim of this review is to assess long-term rates of cancer and adenoma development in patients with FAP after prophylactic surgery and to summarise current recommendations for endoscopic management and surveillance of these patients.

MATERIALS AND METHODS

A systematic literature search of studies from January 1946 through to June 2023 was conducted using the PRISMA checklist. The electronic database PubMed was searched.

RESULTS

Fifty-four papers involving 5010 patients were reviewed. Cancer rate in the rectal remnant was 8.8-16.7% in the western population and 37% in the eastern population. The cumulative risk of cancer 30 years after surgery was 24%. Mortality due to cancer in the rectal remnant is 1.1-11.1% with a 5-year survival rate of 55%. The adenoma rate after primary IPAA was 9.4-85% with a cumulative risk of 85% 20 years after surgery and a cumulative risk of 12% for advanced adenomas 10 years after surgery. Cumulative risk for adenomas after ileorectal anastomosis (IRA) was 85% after 5 and 100% after 10 years. Adenomas developed more frequently after stapled (33.9-57%) compared to hand-sewn (0-33%) anastomosis. We identified reports of 45 cancers in patients after IPAA of which 30 were in the pouch body and 15 in the rectal cuff or at the anastomosis.

CONCLUSIONS

There was a significant incidence of cancer and adenomas in the rectal remnant and ileal pouch of FAP patients during the long-term follow-up. Regular endoscopic surveillance is recommended, not only in IRA patients, but also in pouch patients after proctocolectomy.

Mechanisms of Action of Phytoestrogens and Their Role in Familial Adenomatous Polyposis

Familial adenomatous polyposis (FAP) is a rare disease characterized by the development of adenomatous polyps in the colon and rectum already in adolescence. If left untreated, patients develop colorectal cancer (CRC) with a 100% probability. To date, the gold standard of FAP management is surgery, which is associated with morbidity and mortality. A chemopreventive agent capable of delaying, preventing and reversing the development of CRC has been sought. Several classes of drugs have been used but to date no chemopreventive drug has been found for the management of this disease. In recent years, the importance of estrogen receptors in FAP and CRC, particularly the β subtype, has emerged. Indeed, the expression of the latter is strongly reduced in adenomatous polyps and CRC and is inversely correlated with the aggressiveness of the disease. Since phytoestrogens have a high affinity for this receptor, they have been suggested for use as chemopreventive agents in FAP and CRC. A combination of phytoestrogens and insoluble fibres has proved particularly effective. In this review, the various mechanisms of action of phytoestrogens were analyzed and the effectiveness of using phytoestrogens as an effective chemopreventive strategy was discussed.

Safety and efficacy of laparoscopic near-total colectomy and ileo-distal sigmoid anastomosis as a modification of total colectomy and ileorectal anastomosis for prophylactic surgery in patients with adenomatous polyposis syndromes: a comparative study

AIM

Colectomy in patients with adenomatous polyposis (AP) syndromes demands good oncological and surgical outcome. Total colectomy with ileorectal anastomosis (TC-IRA) is one surgical option for these patients. Anastomotic leakage rates of 11% have been reported following TC-IRA. Ileo-distal sigmoid anastomosis (IDSA) is a recent modification of our practice. Our aim was to compare postoperative outcome in patients with AP following near-total colectomy with IDSA (NT-IDSA) and TC-IRA at a single institution.

METHOD

A prospectively maintained database was reviewed to identify patients with AP who underwent laparoscopic NT-IDSA and TC-IRA. Patient demographics, early morbidity and mortality and outcome of endoscopic surveillance were evaluated.

RESULTS

A total of 191 patients with AP underwent laparoscopic colectomy between 2006 and 2017, of whom 139 (72.8%) underwent TC-IRA and 52 (27.2%) NT-IDSA. The median age at surgery in the TC-IRA and NT-IDSA groups was 20 years (IQR 17-45) and 27 years (IQR 19-50), respectively. Grade II complications were comparable between the two groups. There were no anastomotic leakages in the NT-IDSA group compared with 15 (10.8%) in the TC-IRA group (P = 0.0125) and no reoperation in the NT-IDSA group compared with 17 (12.2%) in the TC-IRA group (P = 0.008). The frequency of polypectomies per flexible sigmoidoscopy was comparable between the two groups.

CONCLUSION

This study demonstrates that laparoscopic NT-IDSA for polyposis is associated with a significant improvement in anastomotic leakage rates and surgical outcome. It is too soon to tell whether NT-IDSA alters the need for further intervention, either endoscopic polypectomy or further surgery.

Comparison of proctocolectomy and ileal pouch-anal anastomosis to colectomy and ileorectal anastomosis in familial adenomatous polyposis

Prophylactic surgical options for familial adenomatous polyposis (FAP) are either colectomy and ileorectal anastomosis (IRA) or proctocolectomy and ileal pouch-anal anastomosis (IPAA). The aim of this study was to analyse the short-term and long-term outcomes of these two operative techniques. All patients with FAP in Finland have been prospectively recorded in a database since 1963 were retrospectively reviewed in this analysis. Altogether 140 (61%) colectomies with IRA and 88 (39%) proctocolectomies with IPAA have been performed. Complications occurred in 28 (21%) patients after IRA and in 26 (30%) patients after IPAA. There were 15 (11%) severe complications for IRA and 5 (6%) for IPAA. Twenty-one (15%) patients of the IRA group ended up in conventional ileostomy whereas 3 (3.4%) patients of the IPAA group had their ileal reservoir converted to an ileostomy (p = 0.01). Cumulative survival for IRA was lower than for the IPAA (p = 0.03), but if accounting only for operations made after the IPAA era had commenced, there was no significant difference. IPAA was associated with improved long-term survival without an increase in postoperative complications. The risk of death after colectomy and IRA seemed to be predominantly related to the remaining risk of rectal cancer. Therefore, we favour proctocolectomy with IPAA as the prophylactic surgical procedure for FAP with intermediate or severe polyposis.

Risk of cancer in the rectal remnant after ileorectal anastomosis in patients with familial adenomatous polyposis: single center experience

BACKGROUND AND AIM

We aimed to evaluate the long-term risk of cancer in the rectal remnant in patients with familial adenomatous polyposis after ileorectal anastomosis.

METHODS

Cumulative incidence and clinicopathological characteristics of cancer in the rectal remnant were retrospectively investigated in 27 patients with familial adenomatous polyposis who had undergone ileorectal anastomosis.

RESULTS

During the follow-up period ranging from 3.0 to 35.0 years (median, 21.1 years), cancer in the rectal remnant developed in 10 patients. Cumulative risk of cancer in the rectal remnant 30 years after surgery was 57%. Five patients had metastases and three patients died of cancer in the rectal remnant after proctectomy. There was a trend towards a higher incidence of cancer in the rectal remnant in patients with small-intestinal adenoma and congenital hypertrophy of the retinal pigment epithelium. Multivariate analysis revealed that the ocular lesion was an independent risk factor associated with cancer in the rectal remnant.

CONCLUSION

Subtotal colectomy with ileorectal anastomosis does not seem to be an appropriate prophylactic surgery in patients with familial adenomatous polyposis.

Rectal cancers in patients with familial adenomatous polyposis

Patients with familial adenomatous polyposis may develop rectal cancer at their initial presentation (primary) or after colectomy and ileorectal anastomosis (secondary). Little is known about whether differences in presentation impact survival. We hypothesize that patients with secondary rectal cancer have better oncologic outcomes. Patients with rectal cancer in the context of familial adenomatous polyposis were classified into 3 groups: known rectal cancer at presentation, incidental rectal cancer unrecognized before proctocolectomy, and rectal cancer diagnosed after ileorectal anastomosis. Primary endpoint was 5-year survival. There were 58 patients, 39 with primary rectal cancer, 5 of which were incidental, and 19 with secondary rectal cancer. Median ages at diagnosis were 32 years (range 14-56) for primary cancer, 35 years (range 22-56) for incidental cancer and 49 years (range 24-66) for secondary cancer (p = 0.001). 76% of those with primary rectal cancer had symptoms, similar to those with incidental cancer (60%) but more than secondary cancer (21%) (p < 0.001). 47% of primary cancers were advanced (stages III and IV) compared to 20% of incidental cancers and 32% of secondary cancers. There was no local recurrence in any patient, but 9 patients had distant recurrences (16% overall). Overall 5-year survival of patients with primary cancer was 72.4%, incidental cancer was 100%, and secondary cancer was 69.7% (p = 0.031). More patients with primary rectal cancer have advanced disease but survival is similar to those with cancer diagnosed on surveillance. More patients with primary rectal cancer have a restorative resection when compared to other groups.

Risk of cancer and secondary proctectomy after colectomy and ileorectal anastomosis in familial adenomatous polyposis

PURPOSE

The aim of our retrospective study was to review the outcome of patients undergoing colectomy with ileorectal anastomosis (IRA) due to familial adenomatous polyposis (FAP) in Finland during the last 50 years.

METHODS

The cumulative risk of rectal cancer and the rate of anus preservation were analyzed. A total of 140 FAP patients with previous colectomy combined with ileorectal anastomosis were included. Kaplan-Meier analysis was performed to evaluate cumulative risks.

RESULTS

Secondary proctectomy was performed for 39 (28 %) of 140 patients. The cumulative risk of secondary proctectomy was 53 % at 30 years after colectomy with IRA. A total of 17 (44 %) secondary proctectomies were performed due to cancer or suspicion of cancer, and another 17 (44 %) secondary proctectomies were performed due to uncontrollable rectal polyposis. During our study, the anus preservation rate in secondary proctectomies was 49 %. The cumulative risk of rectal cancer was 24 % at 30 years after colectomy with IRA. Therefore, the cumulative rectal cancer mortality 30 years after colectomy with IRA was 9 %.

CONCLUSIONS

Proctocolectomy and ileal pouch-anal anastomosis (IPAA) should be favored as a primary operation for patients not having technical or medical contraindications for it because colectomy with IRA carried a rectal cancer risk of 13 % with a mortality of 7 % during our study, and because IPAA is likely to succeed better at earlier phase of the disease. Patients with attenuated FAP had no rectal cancer in our study, and they may form a group where IRA should still be the first choice as an exception.

Risk of ileal pouch neoplasms in patients with familial adenomatous polyposis

Restorative proctocolectomy is the most common surgical option for patients with familial adenomatous polyposis (FAP). However, adenomas may develop in the ileal pouch mucosa over time, and even carcinoma in the pouch has been reported. We therefore reviewed the prevalence, nature, and treatment of adenomas and carcinoma that develop after proctocolectomy in the ileal pouch mucosa in patients with FAP. In 25 reports that were reviewed, the incidence of adenomas in the ileal pouch varied from 6.7% to 73.9%. Several potential factors that favor the development of pouch polyposis have been investigated, but many remain controversial. Nevertheless, it seems certain that the age of the pouch is important. The risk appears to be 7% to 16% after 5 years, 35% to 42% after 10 years, and 75% after 15 years. On the other hand, only 21 cases of ileal pouch carcinoma have been recorded in the literature to date. The diagnosis of pouch carcinoma was made between 3 to 20 years (median, 10 years) after pouch construction. Although the risk of malignant transformation in ileal pouches is probably low, it is not negligible, and the long-term risk cannot presently be well quantified. Regular endoscopic surveillance, especially using chromoendoscopy, is recommended.

Familial adenomatous polyposis: challenges and pitfalls of surgical treatment

Surgical management of familial adenomatous polyposis (FAP) is complex and requires both sound judgment and technical skills. Because colorectal cancer risk approaches 100%, prophylactic colorectal surgery remains a cornerstone of management. Both patient factors and disease characteristics influence surgical decision-making regarding the timing of prophylactic surgery, the extent of resection, and types of reconstruction. Making appropriate choices can be challenging and there is continued debate regarding optimal strategies. This chapter reviews the controversies in colorectal surgery for FAP.

The prognosis of clinical course and the analysis of the frequency of the inflammation and dysplasia in the intestinal J-pouch at the patients after restorative proctocolectomy due to FAP

PURPOSE

The main operative method in familial adenomatous polyposis (FAP) patients is restorative proctocolectomy with "J"-shaped pouch and temporary loop ileostomy. The aim of the study was the analysis of the frequency of the dysplasia and inflammation in the intestinal pouch and prognosis of the clinical course in FAP patients after restorative proctocolectomy.

METHODS

A group of 165 FAP patients (86 females and 79 males, mean age 22.49 ± 12) subjected to a restorative proctocolectomy in the years 1985-2009 was analyzed. Clinical data coming from follow-up observation in the period of 2004-2009 were evaluated. In all patients, clinical examination and endoscopy with polypectomy and/or biopsy of pouch mucosa were done.

RESULTS

The mean time of pouchitis occurrence after an ileal pouch-anal anastomosis was 6 months. Mean time for low-grade dysplasia was 14 months. The time difference of low-grade dysplasia after the above procedure as compared to pouchitis alone was substantial. Mean time for high-grade dysplasia was 16 months and for neoplasia even 19 months. It was estimated that early pouchitis happening within the first year after surgery occurs in 5% of patients, low-grade dysplasia 4 years later in 7% of cases, high-grade dysplasia 7 years later in around 10% of patients and neoplasia 14 years after surgery in 15% of cases.

CONCLUSIONS

In conclusion, the Polyposis Registry encompassing whole country is the best way of controlling FAP patients. The regular lifelong endoscopic monitoring gives the opportunity of the early detection of the dysplasia and can protect against neoplasia.

Rectum-sparing surgery may be appropriate for biallelic MutYH-associated polyposis

PURPOSE

The risk of cancer or severe polyposis of the rectal stump after total colectomy for MutYH-associated polyposis is scarcely defined. To evaluate this risk, we describe the findings of endoscopic surveillance of the rectal stump in a series of patients with biallelic MutYH mutations and polyposis.

METHODS

This is a retrospective, observational, multicenter case series derived from 2 familial cancer registries. Biallelic, germ-line MutYH mutations were found in 14 patients with no adenomatous polyposis coli gene mutations. Eleven of them underwent total colectomy with ileorectal anastomosis and yearly proctoscopic surveillance thereafter. Phenotype and histology of rectal polyps were recorded at diagnosis and during follow-up. Development of adenomas and carcinomas during endoscopic surveillance of the rectal stump was observed.

RESULTS

At diagnosis, 6 patients had attenuated polyposis (10-100 adenomas), 5 patients had classical polyposis, 8 patients had colon carcinoma, and no patient had rectal carcinoma. The mean number of rectal polyps at diagnosis was 2.64 ± 2.11 (range, 0-6). No patients had rectal cancer. The most frequent MutYH mutations were Y165C/Y165C and G382D/G382D in 6 and 2 patients, respectively. During surveillance of the rectal stump after surgery (median duration, 5 y; range, 2-23 y), no patient developed rectal cancer. The mean number of adenomas per proctoscopy was 1.23 ± 2.19 (range, 0-10 adenomas per proctoscopy). This study was limited by the small size and retrospective nature of the case series.

CONCLUSION

Total colectomy with ileorectal anastomosis may be appropriate for patients with MutYH-associated polyposis, provided that they have no rectal cancer or severe rectal polyposis at presentation and that they undergo yearly endoscopic surveillance thereafter.

Surgical treatment of familial adenomatous polyposis: ileorectal anastomosis or restorative proctolectomy?

CONTEXT

Controversy regarding the best operative choice for familial adenomatous polyposis lays between the morbidity of restorative proctocolectomy and the supposed mortality due to rectal cancer after ileorectal anastomosis.

OBJECTIVES

To evaluate operative complications and oncological outcome after ileorectal anastomosis and restorative proctocolectomy.

METHODS

Charts from patients treated between 1977 and 2006 were retrospectively analyzed. Clinical and endoscopic data, results of treatment, pathological reports and information regarding early and late outcome were recorded.

RESULTS

Eighty-eight patients - 41 men (46.6%) and 47 women (53.4%) - were assisted. At diagnosis, 53 patients (60.2%) already had associated colorectal cancer. Operative complications occurred in 25 patients (29.0 %), being 17 (19.7%) early and 8 (9.3%) late complications. There were more complications after restorative proctocolectomy (48.1%) compared to proctocolectomy with ileostomy (26.6%) and ileorectal anastomosis (19.0%) (P = 0,03). There was no operative mortality. During the follow-up of 36 ileorectal anastomosis, cancer developed in the rectal cuff in six patients (16,6%). Cumulative cancer risk after ileorectal anastomosis was 17.2% at 5 years, 24.1% at 10 years and 43.1% at 15 years of follow-up. Age-dependent cumulative risk started at 30 years (4.3%), went to 9.6% at 40 years, 20.9% at 40 years and 52% at 60 years. Among the 26 patients followed after restorative proctocolectomy, it was found cancer in the ileal pouch in 1 (3.8%).

CONCLUSIONS

1. Operative complications occurred in about one third of the patients, being more frequently after the confection of ileal reservoir; 2. greater age and previous colonic carcinoma were associated with the development of rectal cancer after ileorectal anastomosis; 3. patients treated by restorative proctocolectomy are not free from the risk of pouch degeneration; 4. the disease complexity and the various risk factors (clinical, endoscopic, genetic) indicate that the best choice for operative treatment should be based on individual features discussed by a specialist; 5. all patients require continuous and long-term surveillance during postoperative follow-up.

Evaluation of 28 years of surgical treatment of children and young adults with familial adenomatous polyposis

BACKGROUND

In this retrospective study, 28 years of surgical treatment of children and young adults with familial adenomatous polyposis (FAP) was analyzed.

METHODS

Forty-three patients were operated on before the age of 26 years. Endoscopic aspects, operative data, and complications were analyzed, and the resection specimens were reevaluated. Functional outcome was assessed by telephone questionnaire.

RESULTS

Primary ileorectal anastomosis (IRA) was performed in 34 patients with a mean age of 16 years (range, 7-25 years). Primary ileal-pouch anal anastomosis (IPAA) was performed in 9 patients at a mean age of 19 years (range, 15-24 years). Secondary excision of the rectum was performed in 7 patients. Overall, rectal carcinoma was present in 4 patients, at the age of 35, 36, 37, and 38 years. Two patients, aged 39 and 40 years, died because of invasive carcinoma with distant metastasis. The functional outcome and postoperative complications after both procedures were similar to those described in literature for children with FAP. Most patients did not experience alterations in lifestyle, and there was no urinary incontinence.

CONCLUSIONS

In this retrospective study, both IRA and IPAA showed to be feasible techniques in young patients with FAP. A prospective study with a sufficient follow-up is needed to compare both techniques in this specific group of patients.

Long-term outcome of metachronous rectal cancer following ileorectal anastomosis for familial adenomatous polyposis

BACKGROUND

Total colectomy with ileorectal anastomosis (IRA) for familial adenomatous polyposis (FAP) carries a potential risk of metachronous cancer in the residual rectum. This study evaluated the risk of cancer development in the residual rectum.

METHODS

Ninety-six patients who underwent initial surgery for prevention and cure of FAP were studied, and a clinicopathologic comparison was conducted between 59 patients who underwent IRA and 24 who underwent total proctocolectomy.

RESULTS

The 5-year overall survival rates were 94% after IRA and 95% after total proctocolectomy with no significant difference. The incidence of dense-type rectal polyps (4/17, 24%) was significantly higher in patients who developed metachronous rectal cancer following IRA compared to that in patients who did not (1/39, 3%). Moreover, 60% of patients with dense-type colon polyps developed metachronous rectal cancer compared to 24% in patients without and 80% of those with dense type rectal polyps developed metachronous rectal cancer compared to 25% without. Endoscopic surveillance of the eight Tis or T1 patients was performed at intervals of 6 months to 1 year after IRA but was not performed in three T3 patients for more than 2 years.

CONCLUSIONS

Effective IRA requires selection of patients without invasive rectal cancer and without dense rectal polyps in whom long-term postoperative follow-up of the residual rectum is possible.

Rectal and pouch recurrences after surgical treatment for familial adenomatous polyposis

BACKGROUND

Familial adenomatous polyposis (FAP) is a genetic disease characterized by multiple adenomatous colorectal polyps and different extracolonic manifestations (ECM). The present work is aimed to analyze the outcome after surgical treatment regarding complications and cancer recurrence.

METHODS

Charts from patients treated between 1977 and 2006 were retrospectively analyzed. Clinical and endoscopic data, results of treatment, pathological reports and information about recurrence were collected.

RESULTS

Eighty-eight patients (41 men [46.6%] and 47 women [53.4%]) were assisted. At diagnosis, associated colorectal cancer (CRC) was detected in 53 patients (60.2%), whose average age was higher than those without CRC (40.0 vs. 29.5 years). At colonoscopy, polyposis was classified as attenuated in 12 patients (14.3%). Surgical treatment consisted in total proctocolectomy with ileostomy (PCI, 15 [17.4%]), restorative proctocolectomy (RPC, 27 [31.4%]), total colectomy with ileal-rectum anastomosis (IRA, 42 [48.8%]), palliative segmental resection (1 [1.2%]) and internal bypass (1 [1.2%]). Two patients were not operated on due to religious reasons and advanced disease. Complications occurred in 25 patients (29.0%), more commonly after RPC (48.1%). There was no operative mortality. Local or distant metastases were detected in six (11.3%) patients with CRC treated to cure. During the follow-up of 36 IRA, cancer developed in the rectal cuff in six patients (16.6%), whose average age was higher than in patients without rectal recurrence (45.8 vs. 36.6 years). Five of them have had colonic cancer in the resected specimen. Among the 26 patients followed after RPC, cancer in the ileal pouch developed in 1 (3.8%).

CONCLUSIONS

(1) Within the present series, FAP patients presented a high incidence of associated CRC and diagnosis was generally established after the third decade of life; (2) operative complications occurred in about one third of the patients, being more frequent after the confection of an ileal reservoir; (3) rectal cancer after IRA was detected in 16.6% of patients and it was associated with greater age and previous colonic carcinoma; (4) both continuous and long-term surveillance of the rectal stump and ileal pouch are necessary during follow-up.

Hereditary colorectal cancer syndromes: familial adenomatous polyposis and lynch syndrome

Familial colorectal cancer (CRC) accounts for 10% to 20% of all cases of CRC. Two major autosomal dominant forms of heritable CRC are familial adenomatous polyposis (FAP) and Lynch syndrome (also known as hereditary nonpolyposis colorectal cancer). Along with the risk for CRC, both syndromes are associated with elevated risk for other tumors. Improved understanding of the genetic basis of these diseases has not only facilitated the identification and screening of at-risk individuals and the development of prophylactic or early-stage intervention strategies but also provided better insight into sporadic CRC. This article reviews the clinical and genetic characteristics of FAP and Lynch syndrome, recommended screening and surveillance practices, and appropriate surgical and nonsurgical interventions.

Colectomy and ileorectal anastomosis is still an option for selected patients with familial adenomatous polyposis

PURPOSE

The risk of rectal cancer after colectomy and ileorectal anastomosis may be reduced in the last decades, as patients with severe polyposis now have an ileoanal pouch. We have reevaluated the risk of rectal cancer and proctectomy for all causes according to the year of operation.

METHODS

On the basis of the year of operation in 776 patients with ileorectal anastomosis and 471 pouch patients in Denmark, Finland, Holland, and Sweden, the "pouch period" was defined to start in 1990. Ileorectal anastomosis follow-up data was captured by May 31, 2006. The cumulative risk of rectal cancer and proctectomy was compared before and after 1990 by Kaplan-Meier analysis.

RESULTS

In the prepouch period 56/576 patients (10 percent) developed rectal cancer, vs. 4/200 (2 percent) in the pouch period. Neither the cumulative risk of rectal cancer (p = 0.07) nor the cumulative risk of proctectomy (p = 0.17) changed. However, in females the cumulative risk of rectal cancer (p = 0.04) and of proctectomy (p = 0.03) were lower in the pouch period.

CONCLUSIONS

Since the introduction of the ileoanal pouch rectal cancer has decreased after ileorectal anastomosis, but only statistically significant in females. This indicates that ileorectal anastomosis may still be justified in selected patients with mild adenomatosis, especially in young females.

A proteomics approach to identify changes in protein profiles in serum of Familial Adenomatous Polyposis patients

Familial adenomatous polyposis (FAP) is one of the most important clinical hereditary forms of inherited susceptibility to colorectal cancer and is characterized by a high degree of phenotypic heterogeneity. We used a mass spectrometry driven-proteomic strategy to identify serum molecules differently expressed in FAP patients. The data obtained were subsequently processed by bioinformatic analysis and confirmed by Western blotting. Significant differences were highlighted in the expression of serum proteins of FAP patients. In particular, two proteins (alpha-2-HS-glycoprotein and apoliprotein D) were down-regulated (about 0.5- and 0.7-fold, respectively) in carpeting versus diffuse FAP patients and healthy donors, while alpha-2-antiplasmin was up-regulated (about 1.4-fold). Moreover, mass spectrometry approach enabled us to identify serum biomarkers specific for two distinct clinical form of FAP, i.e. carpeting and diffuse FAP. In particular, vitronectin was up-regulated (more than 1.4-fold) in diffuse FAP patients versus carpeting FAP and versus healthy donors, and two additional proteins (Haptoglobin and alpha-1-acid glycoprotein 1) were up-regulated in 2 out of 3 carpeting FAP patients. Our study suggests that mass spectrometry combined to a strong bioinformatics analysis is a valuable tool for the identification of quali/quantitative differences in the serum proteome of otherwise indistinguishable FAP phenotypes. Moreover, the definition of a proteomic profile, supported by the supervised classification, is a powerful and highly sensitive approach for the identification molecular signatures that are able to outperform the traditional disease markers and can therefore be efficiently applied for the diagnosis and clinical management of FAP patients.