Synchronous Advanced Neoplasia Research Articles

Synchronous Advanced Colorectal Neoplasia: Clinicopathologic Features and Prognostic Significance.

This study aimed to compare the clinico-pathologic features, recurrence rate and disease-free survival between colorectal cancers (CRCs) with synchronous advanced colorectal neoplasia (SCN) and solitary CRCs to determine the prognostic significance of SCN. A retrospective review of prospectively collected data of patients with CRCs was conducted in Phramongkutklao Hospital from January 2009 to December 2014. Patients were categorized in 3 groups: 1) solitary CRCs, 2) CRCs with advanced colorectal adenomas (ACAs) but having no another cancer and 3) synchronous colorectal cancers (S-CRCs) with or without ACAs. Patients undergoing curative resection and complete standard adjuvant treatment were recruited to evaluate the prognostic significance of SCN. Clinicopathologic features, recurrence rate and disease-free survival were analyzed to compare among different groups. Result: Among 328 recruited patients, 282 were classified as solitary CRCs (86%), 23 as CRCs with ACAs (7%) and 23 as S-CRCs (7%). Patients with CRCs with SCN (groups 2 and 3) were significantly older than patients with solitary CRCs (p <0.01), and SCN was found more commonly among males (15.2%) than females (12.3%) (p=0.045). In all, 288 patients achieved a curative resection and accomplished complete standard postoperative adjuvant treatment. Of these, the accumulative number of patients experiencing tumor recurrence was 11.8, 21.2, 24.6, 26.4 and 26.7% at the 1-, 3-, 5-, 7- and 10-year surveillance period, respectively. The disease-free survival of the groups with SCN was marginally higher than that of solitary CRCs groups (p=0.72) (solitary CRCs, 120.7±4.4 months; CRCs/ACAs, 127.4±13.9 months and S-CRCs: 126.2±13.6 months). CRCs with SCN were found at a more advanced age than those with solitary CRCs. SCN was found more often among males than females. After achieving curative resection and complete adjuvant treatment, the recurrence rate and disease-free survival of CRCs with SCN did not significantly differ from those of solitary CRCs.

Rates of synchronous advanced neoplasia and colorectal cancer in patients with colonic serrated lesions.

Serrated lesions (SL) have been associated with significant risks of developing colorectal cancer (CRC). Data on synchronous findings after SL detection during colonoscopy is limited. Study aim was to evaluate the rate of synchronous advanced neoplasia (S-AN) and synchronous CRC (S-CRC) in colonoscopies where SLs were detected. We conducted a retrospective study of screening aged patients 45-74year with colorectal SL (sessile serrated polyp [SSP] or traditional serrated adenoma [TSA]) detected during an elective colonoscopy. Primary outcome was risk of S-AN in patients with SL. Secondary outcomes included risk of S-AN or S-CRC stratified by SL characteristics. The study included 1262 patients with 1649 SLs (1214 with SSPs and 48 with TSAs). 47.2% were female and 22.9% of exams were screening colonoscopies, 48.2% surveillance, 28.9% diagnostic. The overall rates of S-AN and S-CRC were 15.1% and 1.3%, respectively. Presence of SSPs ≥ 10mm was associated with higher rates of S-AN, (18.1 vs. 12.2%, Odds-Ratio [OR] = 1.61 [95% Confidence Interval [CI] 1.17-2.23], p = 0.004). SSP dysplasia was predictive of S-AN, (30.3 vs 14.1%, OR = 2.68 [95%CI 1.24-5.78], p = 0.012) but not S-CRC. SSP number (≥ 3) and location (proximal) were not predictors of S-AN or S-CRC. Patients with SLs are at high-risk of S-AN and S-CRC. Findings of SSPs ≥ 10mm and SSP dysplasia are associated with high-risk of S-AN. Endoscopists should exercise heightened vigilance for synchronous findings when SLs are detected, especially SSPs ≥ 10mm or when bowel preparation is suboptimal. Studies contrasting synchronous risk of other polyp types are needed to confirm these results.

Metachronous advanced neoplasia after submucosal invasive colorectal cancer resection

Little is known about the incidence of metachronous advanced neoplasia (AN) following resection of submucosal invasive colorectal cancer (SM-CRC). Here, we aimed to assess the occurrence of metachronous AN following SM-CRC resection. We retrospectively reviewed consecutive patients who underwent SM-CRC resection at an academic medical center between 2005 and 2013. Among 343 patients, 250 (72.9%) underwent surgical resection or endoscopic resection followed by surgical resection and 93 (27.1%) underwent only endoscopic resection. During a median follow-up period of 61.5 months, the overall incidence of metachronous AN was 7.6%, and the cumulative incidence at 5 years was 6.1%. The cumulative incidence was significantly higher in the endoscopic resection group than in surgical resection group, in patients with colonic disease than in those with rectal disease, and in patients with synchronous AN than in those without. Multivariate analysis revealed that synchronous AN was the only significant risk factor for metachronous AN (HR 4.35; 95% CI 1.88–10.1). These findings imply that depending on synchronous AN, a surveillance protocol following SM-CRC resection can be changed for better detection of metachronous AN.

The prevalence of sessile serrated lesion in the colorectum and its relationship to synchronous colorectal advanced neoplasia: a systemic review and meta-analysis.

The aim of this systemic review and meta-analysis was to evaluate the prevalence of sessile serrated lesion (SSL) and its relationship to synchronous colorectal advanced neoplasia. Comprehensive, computerized research was performed on PubMed and published from 1 January 2010 to 6 July 2018 which searched relevant articles without any language limitations. Clinical trials were included in the narrative systemic review if they matched the following inclusion criteria: (1) published as a case-controlled study, cohort study or cross-sectional study; (2) defined objectively for diagnosis of SSL within the studies; (3) addressed the prevalence and characteristics of SSL. Within these trials, if they met additional criteria involving the reported outcome of risk regarding advanced neoplasia in relation to SSL, they were enrolled into meta-analysis. Forty-one trials were enrolled for the systematic review, with a total of eight analyzed for the meta-analysis. The prevalence of all SSL ranged from 0.038 to 20.23% and the prevalence by pooled analysis was 2.7%. In a subgroup analysis, the overall prevalence of SSL during the periods of 2010-2014 and 2015-2018 was shown to be 2.7 and 2.8%, respectively. We calculated the pooled data on the cancer risk of SSL and the risk of synchronous advanced neoplasia in patients with SSL made available from the eight trials, which resulted in a pooled odds ratio of 3.53 (95% confidence interval 2.39-5.20, I2 = 4%, P = 0.40). In this systemic review, SSL was found to be associated with an increased risk of synchronous advanced neoplasia in the colorectum.

Risk Stratification Based on Synchronous Neoplasia and Clinical Physicochemical Characteristics Predicts a Higher Incidence of Metachronous Advanced Neoplasia in Patients Undergoing Colorectal Resection for Colorectal Cancer.

PurposePatients who undergo primary colorectal cancer (CRC) resection remain at increased risk for metachronous advanced neoplasia (MAN) in the remnant colorectum. This study aimed to investigate the incidence and clinicopathological characteristics predictive of MAN development in the residual colon after surgery.Patients and MethodsWe retrospectively reviewed 450 primary CRC cases referred to our hospital during a 4-year period. Univariate and multivariate analyses were performed to identify risk factors for MAN. The cumulative incidence of MAN was evaluated by the Cox proportional hazards model.ResultsMAN development was confirmed in 78 of the 450 patients (17.3%). Overall 1-, 2-, 3-, and 5-year cumulative probabilities were 0.9%, 4.8%, 9.8%, and 16.1%, respectively, for MAN. Among the clinical and colonoscopic factors at baseline, the independent factors that were significantly associated with MAN were synchronous neoplasia, carcinoembryonic antigen (CEA) level ≥10.0 ng/mL, and index cancer size ≥50 mm. The cumulative probability of MAN was significantly higher for patients with synchronous advanced neoplasia (SAN) than for those without synchronous neoplasia (P = 0.000). A subgroup analysis of patients based on the CEA level and index cancer size indicated that CEA ≥10 ng/mL and index cancer ≥50 mm resulted in a significantly higher cumulative probability of MAN (P = 0.039).ConclusionPatients with SAN or high preoperative serum CEA levels and large index cancer are at increased risk for early-onset MAN. More intensive surveillance strategies may be appropriate for these groups. Risk stratification based on synchronous neoplasia and clinical physicochemical characteristics requires further investigations involving modified appropriate postoperative colonoscopic surveillance schedules.

Relationship between serrated polyps and synchronous and metachronous advanced neoplasia: A retrospective study

Serrated polyps (SP) are regarded as precursor lesions of colorectal cancer (CRC). We conducted this single-center study aiming to investigate the relationship between SP and synchronous and metachronous advanced neoplasia in the Chinese population. The data for this retrospective study were collected from the Endoscopy Center and Department of Gastroenterology of Renji Hospital, School of Medicine, Shanghai Jiao Tong University between May 2012 and May 2019. Altogether 2205 patients were pathologically confirmed with colorectal SP. The detection rate of SP among all polyps has gradually increased since 2014 and reached 8.74% by 2019. Among all the SP cases, 1540 (69.84%) were confirmed as having hyperplasic polyps (HP), 486 (22.04%) were having sessile serrated lesions (SSL), and 171 (7.76%) had traditional serrated adenomas (TSA). Compared with HP (2.14%), SSL and TSA were larger and more likely to be accompanied by synchronous and metachronous advanced neoplasia (6.79% and 6.08%). We next found that large SP (diameter ≥10 mm) (odds ratio [OR] 2.52, 95% confidence interval [CI] 1.40-4.55, P = 0.002) and SSL with high-grade intraepithelial neoplasia (OR 13.85, 95% CI 3.28-58.56, P < 0.001) were associated with an increased risk of synchronous advanced neoplasia. However, we failed to find a relationship between SP and metachronous advanced neoplasia because few patients had developed metachronous advanced neoplasia. Large SP and SSL with high-grade intraepithelial neoplasia are associated with synchronous advanced neoplasia and require timely surveillance.

Detection and clinical characteristics of serrated polyps and conventional adenomas between patients in the outpatient and physical checkup unit receiving colonoscopy.

The sessile serrated adenoma/polyp detection rate (SSA/PDR) among different colonoscopy indications from daily practice has not been fully understood. This study aimed to evaluate the detection and clinical characteristics of serrated polyps and conventional adenomas between outpatient department (OPD) and physical checkup unit (PCU) patients receiving colonoscopy. The data for this retrospective study were collected between 2016 and 2017 at Kaohsiung Veterans General Hospital in Taiwan. A total of 7047 individuals were included, and information on polyp and adenoma detection was extracted from the colonoscopy reports. The adenoma detection rate, the SSA/PDR, and the detection rate of traditional serrated adenoma (TSA) were 32.2%, 0.60%, and 0.50%, respectively. Risk analysis revealed no significant difference (p = 0.095) in SSA/PDR between individuals < 50years and ≥ 50years, and no trend of increased SSA/PDR as age increased was observed (p = 0.320). SSA/P and TSA had higher risks for synchronous advanced neoplasia than conventional adenoma, but with proximal hyperplastic polyps lower (p < 0.001, respectively). No significant difference of SSA/PDR between OPD and PCU patients was observed (p = 1.000); however, the age of SSA/P was significantly older in OPD than in PCU patients (p = 0.048). The detection rates of CA and TSA were associated with age groups; however, SSA/PDR was insignificantly higher among individuals aged < 50years than those with other age groups. In addition, SSA/PDR between OPD and PCU patients was not significantly found in daily practice of colonoscopies.

Prevalence of serrated lesions, risk factors, and their association with synchronous advanced colorectal neoplasia in asymptomatic screened individuals.

Serrated lesions (SLs) have attracted attention as precursors of colorectal cancer (CRC). However, their prevalence, risk factors, and clinical significance have not been satisfactorily elucidated. This study used high-quality colonoscopy data to determine the prevalence of SLs and to identify their risk factors and relationship with synchronous advanced colorectal neoplasia (ACN) in asymptomatic screened individuals. This study included data for 5218 individuals who underwent first-time screening colonoscopy by highly experienced endoscopists. The relationships between baseline characteristics and the presence of SLs and those between the presence of SLs and synchronous ACN were assessed using the chi-squared test and multivariate logistic regression. The proportions of individuals with SLs and right-sided SLs were 23.3% and 7.6%, respectively. Age, sex, family history of CRC, smoking, and body mass index were significantly related with the presence of SLs, and current smoking was most strongly associated with SLs (adjusted odds ratio [aOR] 2.6, 95% confidence interval [CI] 2.1-3.2). The aOR (95% CI) of the presence of SLs, SLs sized ≥10mm, and right-sided SLs≥5mm for synchronous ACN was 1.4 (1.1-1.9), 3.5 (1.3-9.6), and 1.9 (1.0-3.8), respectively. The presence of left-sided SLs≥10mm (without right-sided SLs) was also significantly associated with ACN (aOR 8.1, 95% CI 2.0-33.7). The relatively high prevalence of SLs and risk factors in screened individuals were elucidated and the significant relationship between SLs, particularly SLs≥10mm and right-sided SLs≥5mm, and synchronous ACN was confirmed.

Synchronous Neoplastic Lesions In Referred Patients With Colorectal Cancer: A Retrospective Cohort Study.

BackgroundSynchronous neoplastic lesions are usually present in patients with colorectal cancer (CRC) at diagnosis or postoperative follow-up endoscopy. However, few studies have been published about the clinicopathological features of synchronous lesions, especially those of synchronous advanced neoplasia. This study aimed to describe synchronous lesions in patients with CRC because this knowledge may be useful for preventing the development of metachronous cancer.Material and methodsWe retrospectively reviewed 261 primary CRC cases with synchronous lesions referred to our hospital during a 4-year period. Personal history, habits, family history, characteristics of index cancer, and synchronous lesions were assessed.ResultsIn total, the 261 patients with CRC had 812 synchronous adenomas and 146 advanced neoplasia. Diminutive, small, and large polyps made up 66.7%, 20.2%, and 13.1% of all lesions, respectively; 9.3% of diminutive and small adenomas were advanced neoplasia, and 45.2% of synchronous advanced lesions were subcentimeter polyps. Both synchronous non-advanced lesions and advanced lesions developed most frequently in the distal colon, followed by the proximal colon, and were least frequently found in the rectum (P < 0.001). Older age (P = 0.04) and male gender (P = 0.001) were associated with the presence of advanced neoplasia in CRC cases with synchronous neoplastic lesions. Meanwhile, the use of aspirin may be associated with a lower incidence of advanced neoplasia (P = 0.04).ConclusionPatients diagnosed with CRC require detailed clearing of the remainder of the colon at baseline coloscopy or postoperative follow-up examination, and we should take a more cautious approach to synchronous subcentimeter polyps in this group of patients.

Performance of CT Colonography in Diagnosis of Synchronous Colonic Lesions in Patients With Occlusive Colorectal Cancer.

OBJECTIVE. The purpose of this study was to evaluate the accuracy of CT colonography (CTC) in the diagnosis of synchronous colonic lesions in a cohort of patients with an occlusive colorectal cancer (CRC) causing incomplete colonoscopy. SUBJECTS AND METHODS. Among 109 patients with CRC causing incomplete colonoscopy who underwent CTC with IV contrast enhancement after cathartic purgation, fecal tagging, and colon distention, 70 (mean age, 70 years) for whom reference standards (surgical reports, first surveillance colonoscopy) were available were evaluated. Per-patient and per-lesion sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of CTC in the diagnosis of synchronous colonic lesions measuring 6 mm or larger were assessed. RESULTS. Twenty-seven of the 70 patients (39%) had at least one 6-mm or larger synchronous lesion, and four patients (6%) had a total of five synchronous CRCs. Per-patient sensitivity in diagnosing synchronous CRC was 1.00 (4/4). There were 59 lesions: 20 with a diameter of 10 mm or greater; 30, 6-9 mm; and nine, 5 mm or less. The overall per-patient CTC sensitivity in detecting synchronous lesions 6 mm or larger was 0.93 (25/27); specificity, 0.98 (42/43); PPV, 0.96; and NPV, 0.95. Per-patient sensitivity for the diagnosis of synchronous advanced neoplasia (advanced adenoma and colorectal cancers) was 0.94 (15/16). Per-lesion CTC sensitivity for detecting synchronous lesions 6 mm or larger was 0.88 (37/42); all adenomatous lesions, 0.89 (55/62); and advanced neoplasia, 0.92 (22/24). CONCLUSION. CTC is a highly accurate test for detecting synchronous colonic lesions in patients with occlusive CRC. The prevalence of advanced neoplasia is high (23%).

140 Traditional Serrated Adenomas (TSA) and the Company They Keep: TSA Presence Predicts Synchronous Advanced Lesions

INTRODUCTION: The serrated group of colorectal polyps include hyperplastic polyps (HPs), sessile serrated polyps (SSPs), and traditional serrated adenomas (TSAs). HPs are generally non-precancerous whereas SSPs and TSAs are considered precancerous. TSAs are associated with high risk of subsequent (metachronous) advanced neoplasms, suggesting that TSAs reflect a predisposition for neoplastic progression. If true, the presence of one or more TSAs should be associated with synchronous advanced neoplasms. METHODS: Data was extracted from UCICQD—a prospectively collected database (2012–2019) inclusive of locations, sizes and pathology of all polyps and masses. A “neoplasm” was defined as carcinoma, adenoma, SSP, or TSAs regardless of size. Cases with advanced neoplasm were defined if any neoplasm was malignant, ≥1 cm, contained villous features or high grade dysplasia, or if ≥3 neoplasms of any size were found. TSAs cases were compared to cases of other lesions for rates and odds ratios of synchronous neoplasms and advanced neoplasms. RESULTS: A total of 6023 procedures with at least one HP, adenoma, SSP or TSA were included, of which 70 had one or more TSAs (TSA cases). No significant differences in age, body mass index, or gender were seen between TSA and non-TSA cases. TSA cases had a mean of 2.44 neoplasms compared to 1.72 in non-TSA cases (IIR = 1.42 [CI 1.05–1.92] P = 0.022) and were associated with increased numbers of SSPs (IIR = 1.83 [CI 1.04–3.22] P = 0.038) (Table 1). The fraction of cases with synchronous advanced neoplasia was significantly higher in TSA cases (0.786 ± 0.115) compared to cases with one or more adenomas (0.487 ± 0.016), HPs (0.327 ± 0.019) or SSPs (0.592 ± 0.034), P = 0.0002. Relative to cases with one or more HPs, odds ratios for advanced neoplasia were 1.95 (1.75–2.17), 2.98 (2.54–3.5) and 7.54 (4.23–13.44) for cases with adenoma, SSP and TSA, respectively (Table 2). CONCLUSION: Prior studies have shown that one or more index TSA(s) predict later risk for metachronous advanced neoplasms, more so than an index colorectal carcinoma. We show that the presence of one or more TSAs is also associated with higher risk for synchronous neoplasms and advanced neoplasms, especially SSPs. This suggests that TSA presence may reflect an unknown genetic predisposition and/or intestinal field defect that promotes tumor initiation and malignant progression. Regardless of underlying mechanisms, our data support an aggressive surveillance strategy for patients with one or more TSAs.

211 Increased Synchronous Neoplasms Among Patients With Small and Diminutive Proximal Hyperplastic Polyps

INTRODUCTION: Small right-sided sessile serrated polyps (SSPs) are associated with increased risk of synchronous neoplasia. These lesions are difficult to distinguish from non-precancerous hyperplastic polyps (HPs). Hamoudah et al. published a retrospective cohort study showing that diminutive proximal HPs and SSPs are associated with similar increased rates of synchronous advanced neoplasia among screening colonoscopies. Verification of these findings could impact guidelines that currently consider proximal diminutive HPs as surveillance-irrelevant. METHODS: Our data was extracted from UCICQD—a prospective database (est 2012) with polyp location, size, and pathology. Study design was modeled after that of Hamoudah et al, and included screening colonoscopies divided into: Group 1 (G1)—cases with 1–3 proximal HPs ≤10 mm; Group 2 (G2)- cases with no proximal SSPs or HPs; and Group 3 (G3)—cases with 1–2 proximal SSPs ≤10 mm. Synchronous and advanced neoplasms were compared between G1–G3. RESULTS: Compared to G2, G1 had higher per case rates of synchronous adenomas (52% vs 43%, P = 0.001), 2 or more SSPs (0.6% vs 0.1%, P = 0.046) and 2 or more adenomas (12.4% vs 8.3%, P = 0.01). Compared to G2, G3 had higher per-case rates of synchronous adenomas (50% vs 43%, P = 0.041), SSPs &gt; 9 mm (3.6% vs 0.1%, P &lt; 0.0001) and advanced neoplasms (16.2% vs 11.9%, P = 0.034) (Table 1). Odds ratios (OR) for G1 relative to G2 was significant for 2 or more adenomas (1.48 [1.06–2.08], P = 0.021). For G3 relative to G2, OR were significant for SSP &gt;9 mm (31.05 [9.50–101.55], P &lt; 0.0001). Considering G1 and G3 together, OR relative to G1 were significant for finding of any adenoma (1.19 [1.02–1.38], P = 0.027), SSP &gt; 9 mm (12.72 [3.91–41.44], &lt;0.0001) and &gt;2 adenomas (1.37 [1.04–1.81]) (Table 2). CONCLUSION: Our data confirms Hamoudah et al's findings. Proximal diminutive and small serrated polyps are associated with increased rates and OR for synchronous surveillance relevant and advanced neoplasia. The higher rate of advanced neoplasia among small and diminutive proximal serrated neoplasia was largely accounted for by large SSPs. The surveillance-relevance of proximal small and diminutive serrated lesions is also supported by the increased rate and OR of cases with &gt;2 adenomas. However, studies such as this showing “synchrony” may be insufficient to warrant change in surveillance guidelines, which should be based on “metachrony.”

Yield of Surveillance Colonoscopies 1 Year After Curative Surgical Colorectal Cancer Resections

Endoscopic surveillance after curative colorectal cancer (CRC) resection is routine. However, there is controversy whether the 1-year interval between preoperative and postoperative colonoscopy is justified owing to improved colonoscopy standards. We aimed to assess the yield of surveillance colonoscopies 1 year after CRC surgery. We performed a retrospective cohort study of 572 patients (54.9% male; mean age, 66.2 ± 9.9 y), who underwent curative surgical resection of a first CRC from June 2013 through April 2016 in the Northwest region of The Netherlands. Patients were included if a complete clearing colonoscopy was performed before surgery and the interval between the preoperative and postoperative colonoscopy was 12 months (range, 6-20 mo), conforming to Dutch guidelines. The primary outcome of the study was the yield of CRC at the surveillance colonoscopy performed 1 year after curative resection. A secondary outcome was the yield of advanced neoplasia. After a mean surveillance interval of 13.7 months (±2.8 mo), 10 of 572 patients (1.7%; 95% CI, 0.7%-2.8%) received a diagnosis of CRC. Of these, 5 CRCs were apparently metachronous cancers (3 were stage III or IV) and 5 were recurrences at the anastomosis (1 was stage IV). In 11.4% of patients (95% CI, 8.9%-13.8%), advanced neoplasia was detected at the 1-year follow-up colonoscopy. Synchronous advanced neoplasia at baseline colonoscopy was a risk factor for detection of advanced neoplasia at the follow-up colonoscopy (odds ratio, 2.2; 95% CI, 1.3-3.8; P ≤ .01). Despite high colonoscopy quality, the yield of CRC at surveillance colonoscopy 1 year after CRC resection was 1.7%. These were metachronous CRCs and recurrences, often of advanced stage. The high yield justifies the recommendation of a 1-year surveillance interval after surgical CRC resection.

Clinicopathological features of advanced colorectal serrated lesions: A single‐center study in China

A growing body of evidence indicates that patients with colorectal serrated lesions, especially advanced serrated lesions (ASLs), are at risk of subsequent malignancy. This study aimed to analyze the clinicopathological features of ASLs and the association between ASLs and synchronous advanced colorectal neoplasia (sACN) in a single center of China. A retrospective cross-sectional study of consecutive symptomatic patients and healthy individuals who underwent colonoscopy between January 2010 and March 2016 was performed. Clinicopathological characteritics of the patients with ASLs were documented from the colonoscopy database. Colorectal serrated lesions were pathologically confirmed in 277 (N = 38 981, 0.7%) cases. Among them, 156 (56.3%) were found to have ASLs, with a total of 161 lesions including 71 sessile serrated adenoma/polyps (SSA/P) and 90 traditional serrated adenomas (TSAs). There were no differences in age and gender between the ASL and non-ASL patients. Among the 161 ASLs, 29 (18.0%) were ≥10 mm in diameter. Compared with non-ASLs, ASLs appeared more in the proximal colon (P = 0.007). Flat and subpedunculated lesions were more commonly found in the ASL group compared with the non-ASL group. Nearly all ASLs (160/161) had dysplasia. Moreover, 16 sACN lesions were found in 156 ASL patients, and large diameter (≥10 mm) might be a significant risk factor for sACN (odds ratio 4.35, 95% confidence interval 1.467-12.894, P < 0.05). ASLs are more likely to occur in the proximal colon, and mainly present as flat and sub-pedunculated types. Large ASLs are significantly associated with sACN.

Higher incidence of metachronous advanced neoplasia in patients with synchronous advanced neoplasia and left-sided colorectal resection for colorectal cancer

There is an increased risk of developing metachronous colorectal cancer (CRC) in the remnant colorectum after surgical resection of CRC. We evaluated the incidence of metachronous advanced neoplasia (AN) after surgery for CRC according to resection type and synchronous AN. This cohort study included patients who underwent surgical resection for initial CRC at a tertiary cancer center in Japan between September 2002 and December 2012. The cumulative probability of metachronous AN was calculated using the Kaplan-Meier method and was evaluated by the log-rank test. Metachronous AN was detected in 145 of 1731 included patients, and the 5-year cumulative probability of metachronous AN was 13.1%. There was no significant difference in the incidence of metachronous AN in the right-sided colorectal resection versus left-sided colorectal resection (LCR) groups (log-rank test P= .151), whereas the incidence of metachronous AN was significantly higher in patients with synchronous AN (log-rank test P< .001). In subgroup analysis of patients according to resection type and synchronous AN, the LCR groupwith synchronous AN showed a significantly higher incidence of metachronous AN than the other groups (log-rank test P< .001). We found that synchronous AN, but not resection type, was independently associated with the incidence of metachronous AN in patients who underwent surgical resection of CRC. In addition, subjects with synchronous AN after LCR had a potentially increased risk for metachronous AN. Thus, it may be useful to perform risk stratification according to synchronous AN and resection type.

Patients with small and diminutive proximal hyperplastic polyps have higher rates of synchronous advanced neoplasia compared with patients without serrated lesions

The association of proximal small and diminutive hyperplastic polyps (HPs) with synchronous advanced neoplasia is not well-defined. However, sessile serrated polyps (SSPs), even when small, are known to portend a risk of synchronous neoplasia. Currently, the U.S. Multi-Society Task Force on Colorectal Cancer does not recommend a change in the surveillance interval when proximal small HPs are detected. We aimed to compare the rates of synchronous advanced neoplasia in a screening colonoscopy cohort of patients with small and then diminutive proximal HPs in comparison, first to a cohort absent any serrated or proximal HPs and then in comparison with a cohort with small proximal SSPs. Consecutive screening colonoscopies were recorded between 2005 and 2010 at an academic medical center. Patients were divided into 3 mutually exclusive groups. Group 1 consisted of patients with at least 1 HP that was proximal to the sigmoid colon,<1 cm in endoscopic size, and up to 3 total HPs in number. Group 2 included patients without any proximal HPs or SSPs. Group 3 consisted of patients with 1 to 2 SSPs, with at least 1 being proximal to the sigmoid colon, that were<1 cm in endoscopic size and without dysplasia. Rates of synchronous advanced neoplasia in patients with small (<1 cm) and diminutive (≤5mm) proximal HPs were compared with the rates for the other 2 groups. There were 482 of 2569 patients (18.8%) with a small proximal HP who met the criteria for Group 1. The rate of synchronous advanced neoplasia in patients with a small proximal HP (61/482, 12.7%) was significantly greater compared with the average risk in the non-serrated cohort (Group 2, 133/1878, 7.1%; P< .001). There was no significant difference in the rate of synchronous advanced neoplasia when the small proximal HP group was subdivided by size (≤5mm, 51/404, 12.6% vs 6-9mm, 10/78, 12.8%; P= 1.00). The rate of synchronous advanced neoplasia in patients with diminutive (≤5mm) proximal HPs (51/404, 12.6%) wasnot significantly different from the rate observed with proximal SSPs of similar size (17/113, 15.0%; P= .529). Patients with small and diminutive proximal HPs tend to harbor higher rates of synchronous advanced neoplasia compared with those without any serrated lesions detected on screening colonoscopy. Surveillance outcomes for metachronous advanced neoplasia for patients with small proximal HPs deserves further study. The synchronous advanced neoplasia rate in patients with proximal diminutive HPs is similar to that of proximal diminutive SSPs and could have implications in a resect and discard strategy.

Endoscopic and pathological features of advanced colorectal serrated adenoma

Objective To analyze the clinical and pathological features of advanced colorectal serrated adenoma (ACSA). Methods The endoscopic and pathological features of 156 cases of ACSA and 121 cases of non-ACSA diagnosed in General Hospital, Tianjin Medical University from January 2010 to March 2016 were retrospectively analyzed and compared. Results ACSA and non-ACSA cases accounted for 56.3% (156/277) and 43.7% (121/277) of all patients with colorectal serrated lesions, respectively. The mean age of ACSA patients was 57.79±13.65 years and 89(57.1%) of these patients were male. There was no significant difference in age and gender between ACSA and non-ACSA patients. A total of 161 ACSA lesions were diagnosed, including 71 sessile serrated adenoma/polyps and 90 traditional serrated adenomas. Among the 161 ACSA lesions, there were 29 (18.0%) lesions whose diameter≥10 mm, and 84(52.2%) lesions located in the proximal colon, which were more than non-ACSA (84/161 VS 49/134, P=0.007). ACSA was classified under endoscopy into pedunculated type (20/161), sub-pedunculated type (35/161), sessile type (24/161), flat type (79/161) and laterally spreading tumor (3/161), and the distribution of lesion type was significantly different from non-ACSA (P<0.001). One hundred and sixty(99.4%) ACSA lesions were diagnosed as dysplasia, including 158 low degree dysplasia and 2 high degree dysplasia. Moreover, 16 ACSA patients were accompanied with synchronous advanced colorectal neoplasia(sACN), and large serrated polyps (diameter≥10 mm) might have a strong association with sACN (OR=4.35, 95%CI: 1.467-12.894, P<0.05). Conclusion ACSA is more common in proximal colon and sub-pedunculated type, sessile type and flat type. ACSA diameter≥10 mm is significantly associated with sACN. Key words: Colonoscopy; Advanced colorectal serrated adenoma; Pathological characteristics

Su1649 Higher Incidence of Advanced Neoplasia in Patients With Left-Sided Colorectal Cancer Resection and Synchronous Advanced Neoplasia: Do We Need to Change the Surveillance Protocol Based on the Resection Type and the Baseline Colonoscopy Findings?

Su1649 Higher Incidence of Advanced Neoplasia in Patients With Left-Sided Colorectal Cancer Resection and Synchronous Advanced Neoplasia: Do We Need to Change the Surveillance Protocol Based on the Resection Type and the Baseline Colonoscopy Findings?

Su1734 - Isolated Small Right-Sided Hyperplastic Polyps Confer Higher Rates of Synchronous Advanced Neoplasia Compared to an Average Risk Screening Population

Su1734 - Isolated Small Right-Sided Hyperplastic Polyps Confer Higher Rates of Synchronous Advanced Neoplasia Compared to an Average Risk Screening Population

Incidence, Risk Factors, and Outcomes of Colorectal Cancer in Patients With Ulcerative Colitis With Low-Grade Dysplasia: A Systematic Review and Meta-analysis.

Little is known about outcomes of patients with ulcerative colitis with low-grade dysplasia (UC-LGD). We estimated the incidence of and risk factors for progression to colorectal cancer (CRC) in cohorts of patients with UC-LGD who underwent surveillance (surveillance cohort), and the prevalence of dysplasia-related findings among patients who underwent colectomy for UC-LGD (surgical cohort). We performed a systematic literature review through June 1, 2016, to identify cohort studies of adults with UC-LGD. We estimated pooled incidence rates of CRC and risk factors associated with dysplasia progression in surveillance cohorts, and prevalence of synchronous advanced neoplasia (CRC and/or high-grade dysplasia) in surgical cohorts. In 14 surveillance cohort studies of 671 patients with UC-LGD (52 developed CRC), the pooled annual incidence of CRC was 0.8% (95% confidence interval [CI], 0.4-1.3); the pooled annual incidence of advanced neoplasia was 1.8% (95% CI, 0.9-2.7). Risk of CRC was higher when LGD was diagnosed by expert gastrointestinal pathologist (1.5%) than by community pathologists (0.2%). Factors significantly associated with dysplasia progression were concomitant primary sclerosing cholangitis (odds ratio [OR], 3.4; 95% CI, 1.5-7.8), invisible dysplasia (vs visible dysplasia; OR, 1.9; 95% CI, 1.0-3.4), distal location (vs proximal location; OR, 2.0; 95% CI, 1.1-3.7), and multifocal dysplasia (vs unifocal dysplasia; OR, 3.5; 95% CI, 1.5-8.5). In 12 surgical cohort studies of 450 patients who underwent colectomy for UC-LGD, 34 patients had synchronous CRC (pooled prevalence, 17%; 95% CI, 8-33). In a systematic review of the literature, we found that among patients with UC-LGD under surveillance, the annual incidence of progression to CRC was 0.8%; differences in rates of LGD diagnosis varied with pathologists' level of expertise. Concomitant primary sclerosing cholangitis, invisible dysplasia, distal location, and multifocal LGD are high-risk features associated with dysplasia progression.