Serrated lesions of the colorectum: review and recommendations from an expert panel

Serrated lesions of the colorectum are the precursors of perhaps one-third of colorectal cancers (CRCs). Cancers arising in serrated lesions are usually in the proximal colon, and account for a disproportionate fraction of cancer identified after colonoscopy. We sought to provide guidance for the clinical management of serrated colorectal lesions based on current evidence and expert opinion regarding definitions, classification, and significance of serrated lesions. A consensus conference was held over 2 days reviewing the topic of serrated lesions from the perspectives of histology, molecular biology, epidemiology, clinical aspects, and serrated polyposis. Serrated lesions should be classified pathologically according to the World Health Organization criteria as hyperplastic polyp, sessile serrated adenoma/polyp (SSA/P) with or without cytological dysplasia, or traditional serrated adenoma (TSA). SSA/P and TSA are premalignant lesions, but SSA/P is the principal serrated precursor of CRCs. Serrated lesions have a distinct endoscopic appearance, and several lines of evidence suggest that on average they are more difficult to detect than conventional adenomatous polyps. Effective colonoscopy requires an endoscopist trained in the endoscopic appearance of serrated lesions. We recommend that all serrated lesions proximal to the sigmoid colon and all serrated lesions in the rectosigmoid > 5 mm in size, be completely removed. Recommendations are made for post-polypectomy surveillance of serrated lesions and for surveillance of serrated polyposis patients and their relatives.

ASCO/SSO review of current role of risk-reducing surgery in common hereditary cancer syndromes

Although the etiology of solid cancers is multifactorial, with environmental and genetic factors playing a variable role, a significant portion of the burden of cancer is accounted for by a heritable component. Increasingly, the heritable component of cancer predispositions has been linked to mutations in specific genes, and clinical interventions have been formulated for mutation carriers within affected families. The primary interventions for mutations carriers for highly penetrant syndromes such as multiple endocrine neoplasias, familial adenomatous polyposis, hereditary nonpolyposis colon cancer, and hereditary breast and ovarian cancer syndromes are primarily surgical. For that reason, the American Society of Clinical Oncology (ASCO) and the Society of Surgical Oncology (SSO) have undertaken an educational effort within the oncology community. A joint ASCO/SSO Task Force was charged with presenting an educational symposium on the surgical management of hereditary cancer syndromes at the annual ASCO and SSO meetings, resulting in an educational position article on this topic. Both the content of the symposium and the article were developed as a consensus statement by the Task Force, with the intent of summarizing the current standard of care. This article is divided into four sections addressing breast, colorectal, ovarian and endometrial cancers, and multiple endocrine neoplasia. For each, a brief introduction on the genetics and natural history of the disease is provided, followed by a detailed description of modern surgical approaches, including a description of the clinical and genetic indications and timing of prophylactic surgery, and the efficacy of prophylactic surgery when known. Although a number of recent reviews have addressed the role of genetic testing for cancer susceptibility, including the richly illustrated Cancer Genetics and Cancer Predisposition Testing curriculum by the ASCO Cancer Genetics Working Group (available through http://www.asco.org), this article focuses on the issues surrounding the why, how, and when of surgical prophylaxis for inherited forms of cancer. This is a complex process, which requires a clear understanding of the natural history of the disease and variance of penetrance, a realistic appreciation of the potential benefit and risk of a risk-reducing procedure in a potentially otherwise healthy individual, the long-term sequelae of such surgical intervention, as well as the individual patient and family's perception of surgical risk and anticipated benefit.

Practice parameters for the management of rectal cancer (revised)

The American Society of Colon and Rectal Surgeons is dedicated to assuring high-quality patient care by advancing the science, prevention, and management of disorders and diseases of the colon, rectum, and anus. The Standards Committee is composed of Society members who are chosen because they have demonstrated expertise in the specialty of colon and rectal surgery. This Committee was created to lead international efforts in defining quality care for conditions related to the colon, rectum, and anus. This is accompanied by developing Clinical Practice Guidelines based on the best available evidence. These guidelines are inclusive, and not prescriptive. Their purpose is to provide information on which decisions can be made, rather than dictate a specific form of treatment. These guidelines are intended for the use of all practitioners, health care workers, and patients who desire information about the management of the conditions addressed by the topics covered in these guidelines. It should be recognized that these guidelines should not be deemed inclusive of all proper methods of care or exclusive of methods of care reasonably directed to obtaining the same results. The ultimate judgment regarding the propriety of any specific procedure must be made by the physician in light of all of the circumstances presented by the individual patient.

Calcium antagonistic drugs. Mechanism of action

Calcium antagonists represent a new class of drugs, which were suggested to act by a selective inhibition of Ca2+ influx through cell membranes. We studied the mechanism of action of three calcium antagonists, diltiazem, nifedipine, and verapamil, by investigating the effect on 45Ca uptake and efflux in rat heart and aorta and in rabbit vessels. The uptake of La3+-resistant 45Ca was not decreased by nifedipine or verapamil either in the heart or in the vessels and was increased by diltiazem in rabbit vessels. The efflux of 45Ca from the mesenteric vein of rabbit, originating presumably from intracellular and membrane-boudn fractions, was enhanced by nifedipine. These effects were observed with drug concentrations inhibiting contractions in isolated atria and the spontaneous and norepinephrine-, potassium-, or barium-induced contractions in the portal vein of rats. Thus, our results suggest that calcium antagonistic drugs act by other mechanisms than the inhibition of transmembranous Ca flux, probably on the release and binding of Ca2+ in intracellular pools. The relatively greater inhibition of norepinephrine- than K+-induced contractions in vessels by the calcium antagonistic drugs and the abolition of the inotropic effect of norepinephrine in rat atrium exposed to 0-Ca Krebs solution for a short period are other effects suggesting an intracellular action for these drugs.

The utility of capsule endoscopy small bowel surveillance in patients with polyposis

BACKGROUND

Small intestinal (SI) surveillance is recommended for polyposis patients. The utility and safety of capsule endoscopy (CE) for surveillance of SI neoplasia in patients with familial adenomatous polyposis (FAP) and Peutz-Jeghers syndrome (PJS) is unknown.

METHODS

CE was offered to consecutive FAP and PJS patients due for routine upper endoscopic surveillance. The prevalence, location (jejunum, ileum), size (1-5 mm, 6-10 mm, >10 mm) and number (1-5, 6-12, >20) of polyps detected by CE was assessed.

RESULTS

19 subjects (15 FAP/4 PJS) with a mean age of 43 were included. All subjects had previous intestinal surgery. No complications occurred with CE. CE in FAP: 9/15 (60%) of subjects with FAP had SI polyps. The prevalence of SI polyps was related to the duodenal polyposis stage and subject age. The location, size and number of polyps progressed as duodenal polyposis stage advanced. CE in PJS: 3/4 (75%) of subjects with PJS had SI polyps. The polyps were diffuse in 2/4 and only in the ileum in one subject. CE findings led to laparotomy with intra-operative endoscopic polypectomy in two PJS patients.

CONCLUSION

SI polyps are common in FAP but their importance is unknown. CE should be performed in FAP patients with stage III and IV duodenal disease. Clinically significant polyps are commonly detected by CE in PJS and lead to change in management in 50% of PJS subjects. CE should replace radiographic SI surveillance for PJS patients. CE is safe in polyposis patients who have undergone major intestinal surgery.

Implementation of universal microsatellite instability and immunohistochemistry screening for diagnosing lynch syndrome in a large academic medical center

PURPOSE

In 2009, the Evaluation of Genomic Applications in Practice and Prevention recommended that all colorectal cancers (CRCs) be screened for Lynch syndrome (LS) through microsatellite instability (MSI) or immunohistochemistry (IHC). No studies report how this process is implemented on a health system-wide basis.

METHODS

Since 2004, Cleveland Clinic has screened CRC specimens with MSI/IHC. Between January 2004 and July 2007, MSI/IHC results went only to the colorectal surgeon (approach 1). Between August 2007 and June 2008, colorectal surgeons and a genetic counselor received the MSI/IHC results, and the counselor e-mailed the colorectal surgeon regarding appropriate patients for genetic counseling (GC) referral (approach 2). After July 2008, the colorectal surgeon and counselor received MSI/IHC results, but the counselor contacted the patient to facilitate referral (approach 3). In approaches 2 and 3, patients were presumed to have sporadic CRC if the tumor lacked MLH1 expression and was also BRAF mutated or if the patient was diagnosed at age greater than 72 years and had no cancer family history.

RESULTS

Abnormal MSI/IHC results occurred in 178 (16%) of 1,108 patients. In approach 1, 21 (55%) of 38 patients with abnormal MSI/IHC were referred for GC, 12 (32%) of 38 underwent GC, and 10 (26%) of 38 underwent genetic testing (GT). In approach 2, nine (82%) of 11 patients were referred for GC, seven (64%) of 11 underwent GC, and five (45%) of 11 underwent GT. In approach 3, 56 (100%) of 56 patients were referred for GC, 40 (71%) of 56 underwent GC, and 37 (66%) of 56 underwent GT. Time from referral to GC was 10-fold quicker in approach 3 than approach 1.

CONCLUSION

Implementation of universal MSI/IHC with GC/GT, along with effective multidisciplinary communication and plans of responsibility for patient contact, resulted in increased identification of patients with LS.

Differential effects of dextrorphan and levorphanol on the excitation of rat spinal neurons by amino acids

The effects of the stereoisomers dextrorphan and levorphanol on the excitation of spinal neurons by electrophoretically administered excitatory amino acids were studied in pentobarbitone-anaesthetised rats. Both isomers reduced responses to N-methyl-DL-aspartate (NMA), dextrorphan being both more selective and more potent than levorphanol in this respect. This observation supports the proposal that the NMA-blocking activity of a variety of drugs with psychotomimetic properties is subserved by actions at phencyclidine (PCP)/sigma opiate receptors.

Meta-analysis of observational studies of ileorectal versus ileal pouch-anal anastomosis for familial adenomatous polyposis

BACKGROUND

Surgery for familial adenomatous polyposis (FAP) aims to minimize cancer risk while providing good functional outcome. Colectomy with ileorectal anastomosis and proctocolectomy with ileal pouch-anal anastomosis both offer this, but there is no clear consensus about which is better.

METHODS

This is a meta-analysis of comparative studies published between 1991 and 2003 reporting early and late postoperative adverse events, functional outcomes and quality of life.

RESULTS

Twelve studies containing 1002 patients (53.4 per cent ileal pouch, 46.6 per cent ileorectal anastomosis) were identified. Bowel frequency (weighted mean difference 1.62 (95 per cent confidence interval (c.i.) 1.05 to 2.20)), night defaecation (odds ratio (OR) 6.64 (95 per cent c.i. 2.99 to 14.74)) and use of incontinence pads (OR 2.72 (95 per cent c.i. 1.02 to 7.23)) were significantly less in the ileorectal group, although faecal urgency was reduced with the ileal pouch (odds ratio 0.43 (95 per cent c.i. 0.23 to 0.80)). Reoperation within 30 days was more common after ileal pouch construction (23.4 versus 11.6 per cent; OR 2.11 (95 per cent c.i. 1.21 to 3.70)). There was no significant difference between the techniques in terms of sexual dysfunction, dietary restriction, or postoperative complications. Rectal cancer was a diagnosis only in the ileorectal group (5.5 per cent).

CONCLUSION

Ileal pouch and ileorectal anastomoses have individual merits. Further research is needed to determine which most benefits patients with FAP.

Safety and longterm efficacy of strictureplasty in 314 patients with obstructing small bowel Crohn's disease

BACKGROUND

Since its introduction in the early 1980s, strictureplasty (SXP) has become a viable option in the surgical management of obstructing small bowel Crohn's disease. Questions still remain regarding its safety and longterm durability in comparison to resection. Precise indications and contraindications to the procedure are also not well defined.

STUDY DESIGN

A retrospective review of all patients undergoing SXP for obstructing small bowel Crohn's disease at the Cleveland Clinic between 1984 and 1999 was conducted. A total of 314 patients underwent a laparotomy that included the index SXP The total number of SXPs performed was 1,124, with a median of two (range 1 to 19) per patient. Sixty-six percent of patients underwent a synchronous bowel resection. Recurrence was defined as the need for reoperation. Followup information was determined by personal interviews, phone interviews, or both.

RESULTS

The overall morbidity rate was 18%, with septic complications occurring in 5% of patients. Preoperative weight loss (p = 0.004) and older age (p = 0.008) were found to be significant predictors of morbidity. The surgical recurrence rate was 34%, with a median followup period of 7.5 years (range 1 to 16 years). Age was found to be a significant predictor of recurrence (p = 0.02), with younger patients having a shorter time to reoperation.

CONCLUSIONS

This large series of patients with longterm followup confirms the safety and efficacy of strictureplasty in patients with obstructing small bowel Crohn's disease. The 18% morbidity and 34% operative recurrence rates compare favorably with reported results of resective surgery. Caution should be used in patients with preoperative weight loss, because they experienced higher complication rates. Although young patients seem to follow an accelerated course, SXP remains indicated as part of an overall strategy to conserve intestinal length.

Randomized, controlled trial of carbon dioxide insufflation during colonoscopy

INTRODUCTION

Insufflation of air is a cause of discomfort during and after colonoscopy. Although this can be minimized by good technique, the use of carbon dioxide insufflation may provide further benefits. Carbon dioxide is rapidly absorbed and excreted through the lungs. We hypothesized that carbon dioxide would alleviate post-colonoscopy discomfort.

METHODS

After they had provided informed consent, patients presenting for colonoscopy were randomized into two groups: those in whom air was used for colonoscopy and those in whom carbon dioxide was used. Pain during and ten minutes after colonoscopy was measured on a ten-point analog scale. Data are mean and 95 percent confidence limits.

RESULTS

There were 124 patients in the air group and 123 in the carbon dioxide group. Age, body mass index, indication, diagnosis, and number of procedures were similar for the two groups. There were no differences between the groups in the amounts of sedation or analgesia used, the percentage of examinations that were complete (air, 98.4 percent; carbon dioxide, 95.2 percent), or patient satisfaction (on a scale of 1 to 10: air, 9.4; carbon dioxide, 9.5). Although there were more females in the carbon dioxide group (69 vs. 51), hysterectomy rates were the same. Pain scores (mean +/- 95 percent confidence interval; scale of 1 to 10) immediately after the examination were 4.3 +/- 0.3 for air and 3.6 +/- 0.3 for carbon dioxide (no significant difference). Pain scores 10 minutes later were 2.1 +/- 0.2 for air and 0.9 +/- 0.2 for carbon dioxide (P < 0.05, Student's t-test).

CONCLUSION

Because there was significantly less abdominal pain ten minutes after colonoscopy in the group in whom carbon dioxide was used, carbon dioxide should be considered as an insufflating gas for colonoscopy.

Identification of individuals at risk for Lynch syndrome using targeted evaluations and genetic testing: National Society of Genetic Counselors and the Collaborative Group of the Americas on Inherited Colorectal Cancer joint practice guideline

Identifying individuals who have Lynch syndrome (LS) involves a complex diagnostic work up that includes taking a detailed family history and a combination of various genetic and immunohistochemical tests. The National Society of Genetic Counselors (NSGC) and the Collaborative Group of the Americas on Inherited Colorectal Cancer (CGA-ICC) have come together to publish this clinical practice testing guideline for the evaluation of LS. The purpose of this practice guideline is to provide guidance and a testing algorithm for LS as well as recommendations on when to offer testing. This guideline does not replace a consultation with a genetics professional. This guideline includes explanations in support of this and a summary of background data. While this guideline is not intended to serve as a review of LS, it includes a discussion of background information on LS, and cites a number of key publications which should be reviewed for a more in-depth understanding of LS. These guidelines are intended for genetic counselors, geneticists, gastroenterologists, surgeons, medical oncologists, obstetricians and gynecologists, nurses and other healthcare providers who evaluate patients for LS.

Repair of recurrent rectovaginal fistulas

BACKGROUND

Recurrent rectovaginal fistulas (RRVFs) pose a challenging problem, which can be treated by different surgical procedures. We performed this study to determine the ultimate success rate of various repair techniques.

METHODS

Using a standard data collection form, we retrospectively reviewed charts of patients treated for RRVF.

RESULTS

Between 1991 and 2000, 57 procedures were performed in 35 women who presented with RRVF. Median follow-up was 4 months (interquartile range, 1,25). The causes of RRVF included obstetrical injury (n = 15), Crohn's disease (n = 12), fistula occurring after proctocolectomy with ileal pouch-anal anastomosis (for ulcerative colitis, n = 3; indeterminate colitis, n = 1; familial polyposis, n = 1), cryptoglandular disease (n = 2), and fistula occurring immediately after low anterior resection for rectal cancer (n = 1). The methods of repair used included mucosal advancement flap (n = 30), fistulotomy with overlapping sphincter repair (n = 14), rectal sleeve advancement (n = 3), fibrin glue (n = 1), proctectomy with colonic pull-through (n = 2), and ileal pouch revision (n = 6). Twenty-seven of 34 (79%) patients with adequate follow-up eventually healed after a median of 2 operations. Logistic regression was used to analyze outcome according to etiology of fistula, patient age, number of prior repairs, time interval between last repair and current repair, and presence of fecal diversion. Crohn's disease, the presence of a diverting stoma, and decreased time interval since prior repair were associated with a poorer outcome.

CONCLUSIONS

Most RRVFs can be successfully repaired, although repeated operations may be necessary. Delaying repair may improve outcome.

The neuroprotective action of ketamine and MK-801 after transient cerebral ischemia in rats

The neuroprotective activity of two systemically administered N-methyl-D-aspartate (NMDA) receptor antagonists, ketamine and MK-801, were investigated in a long-term recovery model of near-complete forebrain ischemia in the rat. Doses of each drug were chosen on the basis of the known degree and time course of NMDA antagonism seen in vivo after their systemic administration. Ketamine, administered at a dose of 20 mg.kg-1 iv, either immediately before or shortly after the 10-min ischemic period, failed to lessen neuronal damage in the selectively vulnerable hippocampal CA1 region. Increasing doses of ketamine administered over an increasing length of time in the postischemic period, however, did provide significant protection. MK-801 0.25 or 0.5 mg.kg-1 iv administered before ischemia also resulted in significant protection. The results support the proposal that NMDA receptor-mediated events may contribute to neuronal damage in selectively vulnerable regions of the central nervous system after ischemia.

Risk of rectal cancer in patients after colectomy and ileorectal anastomosis for familial adenomatous polyposis: a function of available surgical options

PURPOSE

One of the concerns with colectomy and ileorectal anastomosis as a prophylactic procedure for patients with familial adenomatous polyposis is the risk of metachronous rectal cancer, estimated at from 12 to 43 percent. These estimates are based largely on surgeries performed at a time when the only alternative option to ileorectal anastomosis for patients with severe familial adenomatous polyposis was proctocolectomy and ileostomy. This study was designed to test the hypothesis that in the pouch era severe polyposis is now treated by proctocolectomy and ileal pouch-anal anastomosis. Ileorectal anastomosis is performed mostly in mildly affected patients and will therefore carry a very low risk of metachronous rectal cancer.

METHODS

Patients undergoing primary prophylactic surgery for familial adenomatous polyposis between 1950 and 1999 were categorized according to the year of their surgery: prepouch era (before 1983) or pouch era (after 1983). Patients undergoing colectomy and ileorectal anastomosis were the focus of the study, and rate of proctectomy and the incidence of rectal cancer were recorded for each group. Data on the severity of the polyposis for each group were abstracted.

RESULTS

A total of 197 patients underwent ileorectal anastomosis, 62 in the prepouch era (median follow-up, 212 months; interquartile range, 148 months) and 135 in the pouch era (median follow-up, 60 months; interquartile range, 80 months). Patients in the prepouch era came to surgery at the same median age as those in the pouch era (median age 23.0 years, interquartile ranges 15.5 years for prepouch and 17 years for pouch). Similar proportions of patients in the prepouch era had severe polyposis (49 percent) as in the pouch era (44 percent), although all severely affected patients had an ileorectal anastomosis in the prepouch era vs. 39 percent in the pouch era. Twenty (32 percent) prepouch-era patients underwent proctectomy compared with three (2 percent) pouch-era patients. No pouch-era patient had rectal cancer on follow-up; eight (12.9 percent) prepouch-era patients did.

CONCLUSION

Although follow-up is shorter, ileorectal anastomosis for familial adenomatous polyposis performed since 1983 carries a much lower rate of rectal cancer and proctectomy than ileorectal anastomosis performed before this time, when restorative proctocolectomy was not an option. This is related, at least in part, to a greater number of patients with severe polyposis having their rectum initially spared.

Differences in results from in vivo and in vitro studies on the use-dependency of N-methylaspartate antagonism by MK-801 and other phencyclidine receptor ligands

We have used microelectrophoretic and intravenous administration of drugs to rat spinal cord neurones in vivo and bath application to rat cortical wedges in vitro to evaluate MK-801 and other phencyclidine (PCP) receptor ligands as N-methylaspartate (NMA) antagonists, paying particular regard to the possible use-dependent nature of their action. MK-801, 0.1-0.5 mg/kg, was a selective and long-lasting NMA antagonist. We were unable to demonstrate significant use-dependent onset of antagonism of NMA by any of the drugs in vivo. Recovery, however, for MK-801 was use-dependent. In vitro there was a gradation with MK-801 being very use-dependent, followed by (PCP), cyclazocine and ketamine, the last showing little or no use-dependence. Results of experiments modulating the in vitro environment suggest that a significant difference between the in vitro and in vivo systems was temperature. Raising the temperature of the wedge chamber from 23 to 33 degrees C reduced the use-dependence of MK-801, and lowering the temperature to 13 degrees C increased the use-dependence of PCP. The mechanism of action of PCP receptor ligands is discussed in the light of these results.

Lamivudine in children with human immunodeficiency virus infection: a phase I/II study. The National Cancer Institute Pediatric Branch-Human Immunodeficiency Virus Working Group

The safety, tolerability, pharmacokinetic profile, and preliminary activity of lamivudine (2'-deoxy-3'-thiacytidine), a novel cytidine nucleoside analogue with antiretroviral activity, in human immunodeficiency virus (HIV)-infected children beyond the neonatal period were studied. Ninety children received dosages of 1-20 mg/kg/day. Pharmacokinetic evaluation demonstrated serum and cerebrospinal fluid concentrations that increased proportionally to dose. As of January 1994, 11 children had been withdrawn from study for disease progression and 10 because of possible lamivudine-related toxicity, and 6 had died. CD4 and CD8 cell counts remained stable over 24 weeks in therapy-naive children and decrease slightly in previously treated children. Quantitative immune complex-dissociated p24 antigen and HIV RNA were decreased significantly at 12 and 24 weeks. In vitro resistance to lamivudine was documented in sequential virus isolates from some patients by 12 weeks. Lamivudine was well-tolerated and exhibited virologic activity in children, although future use in children is likely to be in combination antiretroviral regimens.

Staging intra-abdominal desmoid tumors in familial adenomatous polyposis: a search for a uniform approach to a troubling disease

INTRODUCTION

Desmoid tumors are a clinical problem in 12 to 15 percent of patients with familial adenomatous polyposis. There is no predictably effective treatment for intra-abdominal desmoid tumors, which sometimes cause significant complications by their effects on the ureters or bowel. The relative rarity and the clinical heterogeneity of intra-abdominal desmoid tumors make randomized studies difficult to do. In this article a staging system is proposed to make multi-institutional studies easier.

METHODS

Intra-abdominal desmoid tumors can be staged according to their size, clinical presentation and growth pattern.

CONCLUSION

A way of staging intra-abdominal desmoid tumors is proposed to facilitate stratification by disease severity during collaborative studies of various treatments.

Ileoanal pouch neoplasia in familial adenomatous polyposis: an underestimated threat

PURPOSE

Ileal pouch-anal anastomosis is one of the two main options available for the surgical treatment of patients with familial adenomatous polyposis. Its main advantage is the minimal risk of rectal cancer but a possible Achilles heel is the recurrence of epithelial neoplasia at the ileal pouch-anal anastomosis and within the ileal pouch. The significance of ileoanal anastomotic and ileal pouch adenomas is not yet fully appreciated, and there is a false sense of security about this operation. The consequences of worsening pouch polyposis are serious in that endoscopic treatment is unlikely to be an effective way of controlling it. This study has been done to alert those caring for patients with familial adenomatous polyposis to the looming danger of pouch polyposis and to suggest ways to deal with it.

METHODS

Studies reporting ileoanal pouch adenomas, ileal pouch-anal anastomotic cancers, and ileal pouch cancers in patients with familial adenomatous polyposis were reviewed. Reports of adenomas in Kock pouches and in Brooke ileostomies in the setting of familial adenomatous polyposis were included. The primary end points of the study were the time between pouch construction and the diagnosis of neoplasia, the age of the patients at the diagnosis of neoplasia, and the severity of the neoplasia.

RESULTS

There were 18 studies reporting pouch neoplasia, 15 with adenomas, and 3 with cancer. Ten were case reports, five were retrospective studies, and three were prospective studies. All three prospective studies showed that the incidence of pouch adenomas increases with time of follow-up and that the severity of the polyposis varies. The median time from pouch construction to diagnosis of pouch adenomas was 4.7 years and the range was 0.5 to 12 years. There were six studies reporting eight patients with cancer at the ileal pouch-anal anastomosis, diagnosed a median of 8 years after pouch construction (range, 3-20 years). One-half of the cancers were locally advanced (T4) and one-half were not (T1 or T2). One-half followed stapled anastomosis and one-half were after mucosectomy. There were eight case reports of cancer described in an ileostomy in patients with familial adenomatous polyposis. The median time from ileostomy construction to the ileostomy cancers was 25 (range, 9-40) years.

DISCUSSION

The combination of fecal stasis, adenomatous epithelium, and a germline APC mutation is a potent recipe for epithelial neoplasia. There is increasing evidence that this happens in an ileostomy but that the process is much faster in an ileal pouch. Endoscopic treatment of ileal adenomas is likely to be difficult, reducing the options for their control to excising the entire pouch or chemoprevention.

Clonogenic cell assay for anchorage-dependent squamous carcinoma cell lines using limiting dilution

Clonogenic assays under either anchorage-dependent or -independent conditions are very useful for testing the sensitivity of tumor cells to cytotoxic drugs and radiation. These assays have not been widely used with squamous-cell carcinomas (SCC) because of poor tumor-cell viability and poor cloning efficiency, especially in semi-solid media. To find a clonogenic assay suitable for use with human squamous cancers we tested SCC lines, derived in our laboratory from patients with head and neck cancer, for the capacity to form colonies in soft agar and in 96-well plates. Of 13 UM-SCC lines tested for colony formation in agarose, only UM-SCC-11A was capable of growth in conventional semi-solid media. One other line, UM-SCC-14C, produced colonies in agarose only in the presence of epidermal growth factor. In contrast, all 17 of the SCC lines tested exhibited colony formation in adherent cell culture using limiting dilution in 96-well plates. The plating efficiencies of the SCC lines in the 96-well plate assay ranged from 0.02 to 0.52 colonies (wells)/cell whereas the PE values in soft agar were lower, ranging from 0.0055 to 0.0086 colonies/cell. The 96-well plate assay is not affected by cell migration, a problem encountered with some cell lines when clonogenic assays are performed in Petri dishes. UM-SCC-11A was tested for radiation sensitivity both in soft agar and in the 96-well plate assay. Comparable results were obtained. In summary, the majority of SCC cell lines did not form viable colonies in soft agar but the 96-well plate assay was applicable to a broad spectrum of anchorage-dependent human SCC cell lines and provides an efficient method for evaluating clonogenic cell survival.