Assessing Gaps in Surgical Oncology Training: Results of a Survey of General Surgery Residents.

OBJECTIVE: Many general surgeons devote a significant amount of time and effort to the care of cancer patients. There is currently no standardized, national curriculum in Surgical Oncology for General Surgery residents. The objective of this study was to identify gaps in oncology education among General Surgery residents. DESIGN: An anonymous survey design was used in the present study. Residents received an invitation to participate along with a link to an online survey. Interested residents selected the link and completed the 10 minute survey. Binomial logistic regression was performed to ascertain the effects of postgraduate year (PGY) on various perceptions and knowledge relating to surgical oncology. SETTING: The participants included residents from 3 General Surgery residency programs including Florida Atlantic University, The University of Iowa and The University of Connecticut. These are all university-based programs, but residents in each program rotate at several sites each, including both university and community hospitals. PARTICIPANTS: Participants included clinical PGY 1 to 5 categorical general surgical residents, as well as PGY 1 and 2 General Surgery preliminary residents. A total of 135 residents received the email with the link to the survey. Forty-nine residents from all PGY levels responded to the survey. RESULTS: Twenty-one percent of the respondents were familiar with American College of Surgeons Commission on Cancer accreditation, which is a major means of maintaining standards in cancer care across institutions in the United States The majority of residents did not receive formal training in such key areas as chemotherapy and radiation therapy basics, survivorship, palliative care, pain management, and cancer screening regimens. These responses were not significantly different across different levels of training. Most importantly, many residents, particularly those in PGY 3 to 5, do not feel that they will be fully prepared to care for cancer patients at the completion of their training. CONCLUSIONS: The present study provides evidence that regardless of PGY year, residents do not achieve adequate exposure to a variety of cancer-related topics. These include both multidisciplinary cancer care and the operation, accreditation and administration of certified cancer centers. Further, it appears residents do not feel well prepared to provide optimal cancer care at the completion of their training. This data supports the development of a more comprehensive Surgical Oncology curriculum for General Surgery trainees.

Proximal Aberrant Crypt Foci Associate with Synchronous Neoplasia and Are Primed for Neoplastic Progression.

Aberrant crypt foci (ACF) are the earliest morphologically identifiable lesion found within the human colon. Despite their relatively high frequency in the distal colon, few studies have examined the molecular characteristics of ACF within the proximal colon. In the following study, clinical participants (n = 184) were screened for ACF using high-definition chromoendoscopy with contrast dye-spray. Following pathologic confirmation, ACF biopsies were subjected to laser capture microdissection (LCM), and epithelial cells were evaluated for somatic mutations with a customized colorectal cancer mutation panel using DNA-mass spectrometry. Samples were further characterized for microsatellite instability (MSI). Logistic models were used to associate proximal ACF with synchronous (detected during the same procedure) neoplasia. Thirty-nine percent of participants had at least one histologically confirmed proximal ACF. Individuals with a proximal ACF were significantly more likely to present with a synchronous neoplasm (P = 0.001), and specifically, a proximal, tubular, or tubulovillous adenoma (multivariable OR = 2.69; 95% confidence interval, 1.12-6.47; P = 0.027). Proximal ACF were more likely to be dysplastic (52%) compared with distal ACF (13%; P < 0.0001). Somatic mutations to APC, BRAF, KRAS, NRAS, and ERBB2 were detected in 37% of proximal ACF. Hyperplastic ACF were more often MSI-high, but there were no differences in MSI status observed by colonic location. In summary, ACF are identified in the proximal colons of approximately 40% of individuals undergoing chromoendoscopy and more often in patients with synchronous proximal adenomas.Implications: This study provides the most complete set of data, to date, that ACF represent the earliest step in the adenoma-carcinoma sequence but remain below the detection limit of conventional endoscopy.Visual Overview: http//mcr.accrjournals.org/content/molcanres/16/3/486/F1.large.jpg Mol Cancer Res; 16(3); 486-95. ©2017 AACR.

Genomic instability measured by inter-(simple sequence repeat) PCR and high-resolution microsatellite instability are prognostic of colorectal carcinoma survival after surgical resection.

BACKGROUND: During the multiyear progression to colorectal cancer, numerous genomic alterations arise in events ranging from single base mutations to gains or losses of entire chromosomes. A single genetic change might not stand out as an independent predictor of outcome. The goal of this study was to determine if more comprehensive measurements of genomic instability provide clinically relevant prognostic information. METHODS: Our study included 65 sporadic colorectal cancer patients diagnosed from 1987 to 1991 with last follow-up ascertained in 2006. We estimated an overall tally of alterations using the genome-wide sampling technique of inter-(simple sequence repeat [SSR]) polymerase chain reaction (PCR), and evaluated its relationship with all-cause survival. We also extended and sensitized the Bethesda criteria for microsatellite instability (MSI), by analyzing 348 microsatellite markers instead of the normal five. We expanded the MSI categories into four levels: MSI stable (MSS), very low-level MSI, moderately low-level MSI, and classical high-level MSI. RESULTS: Tumors with genomic instability above the median value of 2.6% as measured by inter-SSR PCR, were associated with far greater risk of death compared to tumors with lower levels of genomic instability. Adverse outcome was most pronounced for patients presenting with stage 3 disease. A gradient of increased survival was observed across increasing MSI levels but did not reach statistical significance. CONCLUSION: Our findings suggest genomic instabilities quantified by inter-SSR PCR and increased precision in MSI values may be clinically useful tools for estimating prognosis in colorectal cancer.

Aberrant crypt foci as predictors of colorectal neoplasia on repeat colonoscopy.

OBJECTIVE: To estimate the risk for colorectal neoplasia detected on repeat colonoscopy in relation to aberrant crypt foci (ACF) frequency reported during the previous baseline examination. METHODS: From July 2003 until December 2008, patients had a colonoscopy with an ACF study using a magnifying colonoscope. The distal 20 cm section of colon was sprayed with Methylene Blue to ascertain the ACF frequency, the independent variable. Patients were categorized into low and high ACF count using the median as the cut point. Data collected from consenting patients included age, gender, height, weight, ethnicity, smoking history, family history of colorectal cancer (CRC), and personal history of colorectal neoplasia. A follow-up colonoscopy was performed at an interval as dictated by clinical surveillance guidelines. The main outcome was surveillance detected advanced colorectal neoplasia (SDAN) detected on repeat colonoscopy. Logistic Regression was used to calculate risk of SDAN on repeat colonoscopy in relation to baseline ACF count. RESULTS: 74 patients had a baseline ACF exam and a repeat surveillance colonoscopy. The median ACF was six and thus a high ACF count was >6 ACF and a low ACF count was ≤6 ACF. Patients diagnosed with SDAN were more likely to have had a high ACF number at baseline compared to patients without these lesions at follow-up (adjusted odds ratio = 12.27; 95% confidence interval: 2.00-75.25) controlling for age, sex, smoking, history of prior adenoma, family history of colon cancer, obesity, and time interval to surveillance exam. A sub analysis of our results demonstrated that this relationship was observed in 48 patients who were undergoing a surveillance colonoscopy for a previous adenoma and not those receiving surveillance for a family history of neoplasia. CONCLUSIONS: Increased number of ACF in the distal colorectum was independently associated with substantial risk for future advanced neoplasia. This relationship was observed in patients undergoing surveillance for previous adenomas. Thus, ACF may serve as potential biomarkers in patients with adenomas to help identify patients who may need additional surveillance.

Vitamin D resistance and colon cancer prevention.

Observational studies have been largely consistent in showing an inverse association between vitamin D and an individual's risk of developing colorectal cancer. Vitamin D protection is further supported by a range of preclinical colon cancer models, including carcinogen, genetic and dietary models. A large number of mechanistic studies in both humans and rodents point to vitamin D preventing cancer by regulating cell proliferation. Counterbalancing this mostly positive data are the results of human intervention studies in which supplemental vitamin D was found to be ineffective for reducing colon cancer risk. One explanation for these discrepancies is the timing of vitamin D intervention. It is possible that colon lesions may progress to a stage where they become unresponsive to vitamin D. Such a somatic loss in vitamin D responsiveness bears the hallmarks of an epigenetic change. Here, we review data supporting the chemopreventive effectiveness of vitamin D and discuss how gene silencing and other molecular changes somatically acquired during colon cancer development may limit the protection that may otherwise be afforded by vitamin D via dietary intervention. Finally, we discuss how understanding the mechanisms by which vitamin D protection is lost might be used to devise strategies to enhance its chemopreventive actions.

High-throughput SNP/CGH approaches for the analysis of genomic instability in colorectal cancer.

Colorectal cancer remains a major cancer killer in the US and worldwide. A better understanding of colorectal carcinogenesis may lead to an improved ability to diagnose, treat, and even prevent this disease. Since a genetic model for colorectal cancer was first proposed significant strides have been made in defining the genomic events that occur during colorectal carcinogenesis. Numerous tumor suppressor genes and oncogenes are clearly involved in this process, which is associated with genomic instability and a mutator phenotype. Newer, high-throughput techniques have accelerated our ability to identify and characterize critical genomic events that contribute to this process. The most commonly used of these techniques include array-comparative genomic hybridization and single nucleotide polymorphism arrays. These technologies allow the entire genome to be mapped at high resolution using tens or even hundreds of thousands of markers in a single experiment. These and other high-throughput genomic techniques are also beginning to be applied to patient care in predicting prognosis and response to treatment in patients with colorectal cancer. The development of Next-generation sequencing technologies that can quickly sequence an entire tumor genome will certainly lead to even more advances in our understanding of colorectal carcinogenesis and our ability to diagnose, prevent and treat this disease.

Number of aberrant crypt foci associated with adiposity and IGF1 bioavailability.

BACKGROUND: Dysregulation of the insulin-like growth factor (IGF) system, a common consequence of adiposity-induced insulin resistance, may be a key underlying mechanism linking excess body weight with colon cancer. Evidence has been derived from studies of cancer and polyps. Supporting data about aberrant crypt foci (ACF), putative pre-polyp changes, have been generated only from animal studies to date. METHODS: We randomly selected 26 patients with sex-specific elevated waist-hip-ratio (WHR) and 26 with normal values from a series of 150 patients seeking routine colonoscopy at the University of Connecticut Health Center. Cross-sectional analyses were performed of ACF number (<5, > or = 5) in relation to total IGF1, IGF-binding protein-3 (IGFBP3), insulin, body mass index (BMI), WHR and waist circumference (WC). Visualized ACF in the 20 cm of the distal colon were counted using advanced endoscopic imaging. RESULTS: Patients with > or = 5 ACF had higher BMI, WHR, and WC compared with patients with >5 ACF (p = 0.04, p = 0.03, and p = 0.01, respectively). IGFBP3 was reduced (p = 0.02) and IGF1:IGFBP3 molar ratio was greater (p = 0.03) in patients with > or = 5 ACF. We did not observe significant associations between ACF number and insulin or total IGF1. CONCLUSIONS: Our study provides the first report in humans of a possible association of ACF prevalence and IGF1 bioavailability as characterized by IGF1:IGFBP3 molar ratio and IGFBP3 level. More research is needed to determine whether this relationship is varied by ACF features (e.g., size, dysplasia, molecular changes), synchronous cancer and polyps, and is modified by colon cancer risk factors.

Allelic losses at genomic instability-associated loci in villous adenomas and adjacent colorectal cancers.

Allelic imbalances in premalignant villous adenomas were compared with those in adjacent microdissected colorectal carcinoma that had arisen directly from the adenomas. Carcinoma-adenoma pairs were examined from 17 patients who underwent resections for colorectal cancer. In all, 28 microsatellite markers were examined, from regions of the genome where individual allelic losses have been associated with overall genomic instability in colorectal carcinomas. Microsatellite instability (MSI) was also evaluated for each marker in each tissue type. Loss of heterozygosity for multiple markers was found in 35% of adenomas and 65% of carcinomas; the average fractional allelic loss rate was 2.5 times higher in carcinomas than in adenomas. Of the 17 patients, 4 had MSI for >30% of markers in both adenoma and carcinoma, with no significant differences between the two tissues. Markers with particularly high imbalance rates in adenomas were seen on chromosomes 11, 14, and 15. These findings provide further evidence that genomic instability is an ongoing process during carcinogenesis, with a markedly increased frequency of allelic losses seen in carcinomas, compared with adjacent adenomas. Markers on chromosomes 11, 14, and 15 may become valuable tools in the identification of patients destined to progress to colorectal carcinomas.

Genomic profiles of colorectal cancers differ based on patient smoking status.

Human sporadic colorectal cancer is the result of a lengthy somatic evolutionary process facilitated by various forms of genomic instability. Such instability arises endogenously from mutations in genes whose role is to preserve genomic integrity, and exogenously from environmental agents that generate genomic damage. We have found that cigarette smoking shifts the genomic profiles and genomic instability patterns of colorectal carcinomas. The genomic profiles of 57 consecutive cancers were examined; 31 cases were current or former smokers and 26 were nonsmokers. Genome-wide allelotypes of 348 markers were examined, along with comparative genomic hybridization (CGH) on ordered BAC microarrays, microsatellite instability, and inter-(simple sequence repeat) polymerase chain reaction instability. Tumors from nonsmokers exhibited losses of heterozygosity, particularly on chromosomes 14 and 18, whereas tumors from smokers exhibited a more diffuse pattern of allelic losses. Tumors from smokers exhibited higher overall rates of loss of heterozygosity, but showed lower rates of background microsatellite instability (MSI-L). On BAC array CGH, higher levels of generalized amplifications and deletions were observed in tumors from smokers, differentially affecting male smokers. In the transforming growth factor-beta signaling pathway, MADH4 mutations were more common in tumors from smokers, whereas transforming growth factor-beta RII mutations were more common among nonsmokers.

Genomic instability of human aberrant crypt foci measured by inter-(simple sequence repeat) PCR and array-CGH.

Aberrant crypt foci (ACF) are the earliest identifiable neoplastic lesions in the colon. Thirty-two ACFs were examined for genomic instability in forms detectable either by inter-(simple sequence repeat) PCR or by array comparative genomic hybridization [array-CGH]. One-fourth of ACFs revealed moderate instability by inter-(simple sequence repeat) PCR; none showed amplifications or deletions on array-CGH. The absence of genomic events detectible by BAC array-CGH indicates early events in colorectal tumor progression are typically smaller than the approximate 150 kb size of a BAC clone insert.

Genomic instability measurement in the diagnosis of thyroid neoplasms.

BACKGROUND: Clinically palpable thyroid nodules are present in approximately 10% of the population, although only 5% to 7% of these nodules harbor malignancy. Fine-needle aspiration has become one of the central tools in the diagnostic armamentarium of the surgeon/endocrinologist. There is, however, up to a 30% indeterminate diagnostic rate associated with this technique, resulting in unnecessary surgical interventions for patients harboring benign disease. A second issue of clinical importance is the unreliability of predicting outcomes based either on histologic findings alone or in combination with clinical staging. To address these diagnostic and clinical shortcomings, we have used measurement of genomic instability as a diagnostic and prognostic indicator for thyroid neoplasms. METHODS: Genomic instability of thyroid tissue samples was determined by inter-(simple sequence repeat) PCR, microsatellite instability analysis, and fluorescence in situ hybridization (FISH) on thyroid neoplasms from 22 patients. RESULTS: Inter-(simple sequence repeat) PCR detected genomic instability with an index range 0% to 1.9% (mean, 0.56%) in patients with benign disease, whereas in patients with malignant histologic findings the values ranged from 0% to 6.6% (mean, 2.9%). This difference between benign and malignant values was statistically significant (p =.004). There was no demonstrable microsatellite instability or loss of heterozygosity for six markers examined in this group. Losses of chromosomes 17 and X in benign disease and gains of chromosomes 7, 12, 17, and X in Hurthle cell carcinoma were observed, although not at a significant rate. CONCLUSIONS: Genomic instability as measured by inter-(simple sequence repeat) PCR was significantly higher for malignant diseases compared with benign thyroid tissues, but no such association was seen with aneuploidy or microsatellite instability.