Value of adding dynamic contrast-enhanced MRI visual assessment to conventional MRI and clinical assessment in the diagnosis of complete tumour response to chemoradiotherapy for rectal cancer.

PURPOSE: To determine if DCE-MRI adds diagnostic value to the combined use of T2WI and DWI-MRI in the determination of clinical complete response (cCR) after neoadjuvant treatment (NAT) in patients with locally advanced rectal cancer. METHODS AND MATERIALS: In this IRB-approved, HIPAA-compliant retrospective study, response was assessed using a 5-point confidence score by T2WI and DWI-MRI only ('standard MRI'), then with addition of DCE-MRI. Review of digital rectal exams and endoscopy notes produced a clinical overall response score. The reference standard was CR by histopathology or cCR determined after a minimum of 18 months' follow-up. Diagnostic accuracy and ROC curves were calculated for standard MRI and added DCE-MRI (to detect complete or good response), for clinical evaluation (to detect CR) and for MRI and clinical methods combined. RESULTS: Of 65 patients undergoing NAT, 20 had cCR (31%). Sensitivity, specificity and area under the ROC (AUC) were 0.55, 0.87 and 0.69 for clinical evaluation; 0.42, 0.77 and 0.66 for standard MRI, and 0.53, 0.76 and 0.68 for added DCE-MRI, respectively. Combined clinical evaluation and standard MRI with DCE-MRI resulted in the highest specificity of 0.96 and highest AUC of 0.72. CONCLUSION: For the assessment of cCR after neoadjuvant therapy using clinical and multi-sequence MRI reading strategies, the addition of DCE-MRI increased specificity and PPV, but not significantly. KEY POINTS: • The addition of dynamic contrast-enhanced MRI to standard MRI, including DWI-MRI, may not significantly improve accuracy of response assessment in rectal cancer treatment. • Clinical assessment consisting of digital rectal examination and endoscopy is the most accurate standalone test to assess response to chemoradiotherapy in rectal cancer. • Combining MRI using DWI and DCE with the clinical assessment may potentially improve the accuracy for response assessment in rectal cancer.

Changes in the multidisciplinary management of rectal cancer from 2009 to 2015 and associated improvements in short-term outcomes.

AIM: Significant recent changes in management of locally advanced rectal cancer (LARC) include preoperative staging, use of extended neoadjuvant therapies and minimally invasive surgery (MIS). This study was aimed at characterizing these changes and associated short-term outcomes. METHOD: We retrospectively analysed treatment and outcome data from patients with T3/4 or N+ LARC ≤ 15 cm from the anal verge who were evaluated at a comprehensive cancer centre in 2009-2015. RESULTS: In total, 798 patients were identified and grouped into five cohorts based on treatment year: 2009-2010, 2011, 2012, 2013 and 2014-2015. Temporal changes included increased reliance on MRI staging, from 57% in 2009-2010 to 98% in 2014-2015 (P < 0.001); increased use of total neoadjuvant therapy, from 17% to 76% (P < 0.001); and increased use of MIS, from 33% to 70% (P < 0.001). Concurrently, median hospital stay decreased (from 7 to 5 days; P < 0.001), as did the rates of Grade III-V complications (from 13% to 7%; P < 0.05), surgical site infections (from 24% to 8%; P < 0.001), anastomotic leak (from 11% to 3%; P < 0.05) and positive circumferential resection margin (from 9% to 4%; P < 0.05). TNM downstaging increased from 62% to 74% (P = 0.002). CONCLUSION: Shifts toward MRI-based staging, total neoadjuvant therapy and MIS occurred between 2009 and 2015. Over the same period, treatment responses improved, and lengths of stay and the incidence of complications decreased.

Effectiveness of a multidisciplinary patient care bundle for reducing surgical-site infections.

BACKGROUND: Surgical-site infection (SSI) is associated with significant healthcare costs. To reduce the high rate of SSI among patients undergoing colorectal surgery at a cancer centre, a comprehensive care bundle was implemented and its efficacy tested. METHODS: A pragmatic study involving three phases (baseline, implementation and sustainability) was conducted on patients treated consecutively between 2013 and 2016. The intervention included 13 components related to: bowel preparation; oral and intravenous antibiotic selection and administration; skin preparation, disinfection and hygiene; maintenance of normothermia during surgery; and use of clean instruments for closure. SSI risk was evaluated by means of a preoperative calculator, and effectiveness was assessed using interrupted time-series regression. RESULTS: In a population with a mean BMI of 30 kg/m2 , diabetes mellitus in 17·5 per cent, and smoking history in 49·3 per cent, SSI rates declined from 11·0 to 4·1 per cent following implementation of the intervention bundle (P = 0·001). The greatest reductions in SSI rates occurred in patients at intermediate or high risk of SSI: from 10·3 to 4·7 per cent (P = 0·006) and from 19 to 2 per cent (P < 0·001) respectively. Wound care modifications were very different in the implementation phase (43·2 versus 24·9 per cent baseline), including use of an overlying surface vacuum dressing (17·2 from 1·4 per cent baseline) or leaving wounds partially open (13·2 from 6·7 per cent baseline). As a result, the biggest difference was in wound-related rather than organ-space SSI. The median length of hospital stay decreased from 7 (i.q.r. 5-10) to 6 (5-9) days (P = 0·002). The greatest reduction in hospital stay was seen in patients at high risk of SSI: from 8 to 6 days (P < 0·001). SSI rates remained low (4·5 per cent) in the sustainability phase. CONCLUSION: Meaningful reductions in SSI can be achieved by implementing a multidisciplinary care bundle at a hospital-wide level.

Prognostic aspects of DCE-MRI in recurrent rectal cancer.

OBJECTIVE: To explore whether pre-reoperative dynamic contrast-enhanced (DCE)-MRI findings correlate with clinical outcome in patients who undergo surgical treatment for recurrent rectal carcinoma. METHODS: A retrospective study of DCE-MRI in patients with recurrent rectal cancer was performed after obtaining an IRB waiver. We queried our PACS from 1998 to 2012 for examinations performed for recurrent disease. Two radiologists in consensus outlined tumour regions of interest on perfusion images. We explored the correlation between K(trans), Kep, Ve, AUC90 and AUC180 with time to re-recurrence of tumour, overall survival and resection margin status. Univariate Cox PH models were used for survival, while univariate logistic regression was used for margin status. RESULTS: Among 58 patients with pre-treatment DCE-MRI who underwent resection, 36 went directly to surgery and 18 had positive margins. K(trans) (0.55, P = 0.012) and Kep (0.93, P = 0.04) were inversely correlated with positive margins. No significant correlations were noted between K(trans), Kep, Ve, AUC90 and AUC180 and overall survival or time to re-recurrence of tumour. CONCLUSION: K(trans) and Kep were significantly associated with clear resection margins; however overall survival and time to re-recurrence were not predicted. Such information might be helpful for treatment individualisation and deserves further investigation.

Progressive plasticity during colorectal cancer metastasis.

Metastasis is the principal cause of cancer death, yet we lack an understanding of metastatic cell states, their relationship to primary tumor states, and the mechanisms by which they transition. In a cohort of biospecimen trios from same-patient normal colon, primary and metastatic colorectal cancer, we show that while primary tumors largely adopt LGR5 + intestinal stem-like states, metastases display progressive plasticity. Loss of intestinal cell states is accompanied by reprogramming into a highly conserved fetal progenitor state, followed by non-canonical differentiation into divergent squamous and neuroendocrine-like states, which is exacerbated by chemotherapy and associated with poor patient survival. Using matched patient-derived organoids, we demonstrate that metastatic cancer cells exhibit greater cell-autonomous multilineage differentiation potential in response to microenvironment cues than their intestinal lineage-restricted primary tumor counterparts. We identify PROX1 as a stabilizer of intestinal lineage in the fetal progenitor state, whose downregulation licenses non-canonical reprogramming.

Multivisceral resections for rectal cancer.

BACKGROUND: En bloc resection of adjacent pelvic organ(s) may be needed to achieve clear surgical margins in rectal cancer surgery. An institutional experience is reported with perioperative morbidity and oncological outcomes. METHODS: Patients were identified retrospectively from a prospectively collected institutional database (1992-2010). Outcomes, and clinical and pathological factors were determined from medical records. Estimated overall survival, overall recurrence and local recurrence were compared using the log rank method and Cox regression analysis. RESULTS: Among 1831 patients with rectal cancer, 124 (6·8 per cent) underwent en bloc resection of part or all of an adjacent organ (vagina/uterus/ovary 90, prostate/seminal vesicle 23, bladder/ureter 15, small bowel/appendix 7). Five-year overall survival and local recurrence rates were 53·3 and 18·8 per cent respectively. There was one postoperative death, from multiple organ failure in a patient with liver cirrhosis. Fifty-two patients underwent sphincter-preserving surgery and three (6 per cent) developed an anastomotic leak. On univariable analysis, the only factor associated with local recurrence was completeness of resection (local recurrence rate 15 per cent versus 69 per cent for R0 versus R1 resection; P < 0·001). On multivariable analysis, factors associated with overall survival were sphincter-preserving surgery, absence of metastatic disease and R0 resection. CONCLUSION: Multiple organ resection for locally advanced primary rectal cancer had good oncological outcomes when clear resection margins were achieved.

Dynamic contrast enhanced-MRI for the detection of pathological complete response to neoadjuvant chemotherapy for locally advanced rectal cancer.

OBJECTIVE: To determine the ability of dynamic contrast enhanced (DCE-MRI) to predict pathological complete response (pCR) after preoperative chemotherapy for rectal cancer. METHODS: In a prospective clinical trial, 23/34 enrolled patients underwent pre- and post-treatment DCE-MRI performed at 1.5T. Gadolinium 0.1 mmol/kg was injected at a rate of 2 mL/s. Using a two-compartmental model of vascular space and extravascular extracellular space, K(trans), k(ep), v(e), AUC90, and AUC180 were calculated. Surgical specimens were the gold standard. Baseline, post-treatment and changes in these quantities were compared with clinico-pathological outcomes. For quantitative variable comparison, Spearman's Rank correlation was used. For categorical variable comparison, the Kruskal-Wallis test was used. P ≤ 0.05 was considered significant. RESULTS: Percentage of histological tumour response ranged from 10 to 100%. Six patients showed pCR. Post chemotherapy K(trans) (mean 0.5 min(-1) vs. 0.2 min(-1), P = 0.04) differed significantly between non-pCR and pCR outcomes, respectively and also correlated with percent tumour response and pathological size. Post-treatment residual abnormal soft tissue noted in some cases of pCR prevented an MR impression of complete response based on morphology alone. CONCLUSION: After neoadjuvant chemotherapy in rectal cancer, MR perfusional characteristics have been identified that can aid in the distinction between incomplete response and pCR. KEY POINTS: Dynamic contrast enhanced (DCE) MRI provides perfusion characteristics of tumours. These objective quantitative measures may be more helpful than subjective imaging alone Some parameters differed markedly between completely responding and incompletely responding rectal cancers. Thus DCE-MRI can potentially offer treatment-altering imaging biomarkers.

Mitochondrial proliferation and paradoxical membrane depolarization during terminal differentiation and apoptosis in a human colon carcinoma cell line.

Herbimycin A, a tyrosine kinase inhibitor, induces cellular differentiation and delayed apoptosis in Colo-205 cells, a poorly differentiated human colon carcinoma cell line. Cell cycle analysis in conjunction with end labeling of DNA fragments revealed that G2 arrest preceded apoptotic cell death. Ultrastructural examination of herbimycin-treated cells demonstrated morphologic features of epithelial differentiation, including formation of a microvillar apical membrane and lateral desmosome adhesions. A marked accumulation of mitochondria was also observed. Fluorometric analysis using the mitochondrial probes nonyl-acridine orange and JC-1 confirmed a progressive increase in mitochondrial mass. However these cells also demonstrated a progressive decline in unit mitochondrial transmembrane potential (DeltaPsim) as determined by the DeltaPsim-sensitive fluorescent probes rhodamine 123 and JC-1 analyzed for red fluorescence. In concert with these mitochondrial changes, Colo-205 cells treated with herbimycin A produced increased levels of reactive oxygen species as evidenced by oxidation of both dichlorodihydrofluorescein diacetate and dihydroethidium. Cell-free assays for apoptosis using rat-liver nuclei and extracts of Colo-205 cells at 24 h showed that apoptotic activity of Colo-205 lysates requires the early action of mitochondria. Morphological and functional mitochondrial changes were observed at early time points, preceding cleavage of poly (ADP-ribose) polymerase. These results suggest that apoptosis in differentiated Colo-205 cells involves unrestrained mitochondrial proliferation and progressive membrane dysfunction, a novel mechanism in apoptosis.

Ligase-based detection of mononucleotide repeat sequences.

Up to 15% of all colorectal cancers are considered to be replication error positive (RER(+)) and contain mutations at hundreds of thousands of microsatellite repeat sequences. Recently, a number of intragenic mononucleotide repeat sequences have been demonstrated to be targets for inactivating genes in RER(+)colorectal tumors. In this study, thermostable DNA ligases were tested for the ability to detect alterations in microsatellite sequences in colon tumor samples. Ligation profiles on mononucleotide repeat sequences were determined for four related thermostable DNA ligases, Thermus thermophilus ( Tth ) ligase, Thermus sp. AK16D ligase, Aquifex aeolicus ligase and the K294R mutant of the Tth ligase. While the limit of detection for point mutations was one mutation in 1000 wild-type sequences, the ability to detect a single base deletion in a 10 base mononucleotide repeat was one mutation in 100 wild-type sequences. Furthermore, the misligation error increased exponentially as the length of the mono-nucleotide repeat increased, and was 10% of the correct signal for a 19 base mononucleotide repeat. A fluorescent ligase-based assay [polymerase chain reaction/ligase detection reaction (PCR/LDR)] correlated with results obtained using a radioactive assay to detect instability within the TGF-beta Type II receptor gene. PCR/LDR was also used to detect the APCI1307K mononucleotide repeat allele which has a carrier frequency of 6.1% in Ashkenazi Jewish individuals. In a blind study, 30 samples that had been typed for the presence of the APCI1307K allele were tested. The PCR/LDR results correlated with those obtained using sequencing and allele-specific oligonucleotide hybridization for 16 samples carrying the mutation and 13 wild-type samples. Ligation assays that characterize mononucleotide repeats can be used to rapidly detect somatic mutations in tumors, and to screen for individuals who have a hereditary predisposition to develop colon cancer.

Detecting colorectal cancer in stool with the use of multiple genetic targets.

BACKGROUND: Colorectal cancer cells are shed into the stool, providing a potential means for the early detection of the disease using noninvasive approaches. Our goal was to develop reliable, specific molecular genetic tests for the detection of colorectal cancer in stool samples. METHODS: Stool DNA was isolated from paired stools and primary tumor samples from 51 colorectal cancer patients. Three genetic targets-TP53, BAT26, and K-RAS-were used to detect tumor-associated mutations in the stool prior to or without regard to the molecular analyses of the paired tumors. TP53 gene mutations were detected with a mismatch-ligation assay that detects nine common p53 gene mutations. Deletions within the BAT26 locus were detected by a modified solid-phase minisequencing method. Mutations in codons 12 and 13 of K-RAS were detected with a digital polymerase chain reaction-based method. RESULTS: TP53 gene mutations were detected in the tumor DNA of 30 patients, all of whom had the identical TP53 mutation in their stools. Tumors from three patients contained a noninherited deletion at the BAT26 locus, and the same alterations were identified in these patients' stool specimens. Nineteen of 50 tumors tested had a K-RAS mutation; identical mutations were detected in the paired stool DNA samples from eight patients. In no case was a mutation found in stool that was not also present in the primary tumor. Thus, the three genetic markers together detected 36 (71%) of 51 patients (95% confidence interval [CI] = 56% to 83%) with colorectal cancer and 36 (92%) of 39 patients (95% CI = 79% to 98%) whose tumors had an alteration. CONCLUSION: We were able to detect the majority of colorectal cancers by analyzing stool DNA for just three genetic markers. Additional work is needed to determine the specificity of these genetic tests for detecting colorectal neoplasia in asymptomatic patients and to more precisely estimate the prevalence of the mutations and sensitivity of the assay.

Incisional hernias after laparoscopic and robotic right colectomy.

PURPOSE: Incisional hernia (IH) is a common complication after colectomy, with impacts on both health care utilization and quality of life. The true incidence of IH after minimally invasive colectomy is not well described. The purpose of this study was to examine IH incidence after minimally invasive right colectomies (RC) and to compare the IH rates after laparoscopic (L-RC) and robotic (R-RC) colectomies. METHODS: This is a retrospective review of patients undergoing minimally invasive RC at a single institution from 2009 to 2014. Only patients undergoing RC for colonic neoplasia were included. Patients with previous colectomy or intraperitoneal chemotherapy were excluded. Three L-RC patients were included for each R-RC patient. The primary outcome was IH rate based on clinical examination or computed tomography (CT). Univariate and multivariate time-to-event analyses were used to assess predictors of IH. RESULTS: 276 patients where included, of which 69 had undergone R-RC and 207 L-RC. Patient and tumor characteristics were similar between the groups, except for higher tumor stage in L-RC patients. Both the median time to diagnosis (9.2 months) and the overall IH rate were similar between the groups (17.4 % for R-RC and 22.2 % for L-RC), as were all other postoperative complications. In multivariable analyses, the only significant predictor of IH was former or current tobacco use (hazard raio 3.0, p = 0.03). CONCLUSIONS: This study suggests that the incidence of IH is high after minimally invasive colectomy and that this rate is equivalent after R-RC and L-RC. Reducing the IH rate represents an important opportunity for improving quality of life and reducing health care utilization after minimally invasive colectomy.

Multiplex PCR/LDR for detection of K-ras mutations in primary colon tumors.

Point mutations in codons 12, 13, and 61 of the K-ras gene occur early in the development of colorectal cancer and are preserved throughout the course of tumor progression. These mutations can serve as biomarkers for shed or circulating tumor cells and may be useful for diagnosis of early, curable tumors and for staging of advanced cancers. We have developed a multiplex polymerase chain reaction/ligase detection reaction (PCR/LDR) method which identifies all 19 possible single-base mutations in K-ras codons 12, 13, and 61, with a sensitivity of 1 in 500 wild-type sequences. In a blinded study, 144 paraffin-embedded archival colon carcinomas were microdissected and K-ras mutations determined by both dideoxy-sequencing and multiplex PCR/LDR. Results were concordant for 134 samples. The ten discordant samples were re-evaluated using higher sensitivity uniplex PCR/LDR, and the original multiplex PCR/LDR result was confirmed in nine of these ten cases. Multiplex PCR/LDR was able to identify mutations in solid tumors or paraffin-embedded tissues containing a majority of wild-type stromal cells, with or without microdissection. The technique is well suited for large scale studies and for analysis of clinical samples containing a minority population of mutated cells.

Phase I study of hepatic arterial infusion of floxuridine and dexamethasone with systemic irinotecan for unresectable hepatic metastases from colorectal cancer.

PURPOSE: To determine the maximum-tolerated dose (MTD) and dose-limiting toxicities of concurrent systemic irinotecan and hepatic arterial infusion (HAI) of floxuridine (FUDR) and dexamethasone in patients with unresectable hepatic metastases from colorectal cancer, to determine the safety of this combination in patients who have undergone cryosurgery, and to evaluate the pharmacokinetic effects of HAI FUDR on the metabolism of irinotecan. PATIENTS AND METHODS: Forty-six previously treated patients with unresectable liver metastases and no known extrahepatic disease were treated concurrently with intravenous irinotecan weekly for 3 weeks and with HAI of FUDR and dexamethasone for 14 days (both were recycled in 28 days). Parallel cohorts of patients treated with or without cryosurgery were entered at escalating dose levels. RESULTS: The MTD for patients who did not undergo cryosurgery was 100 mg/m2 of irinotecan weekly for 3 weeks every 4 weeks with concurrent HAI FUDR (0.16 mg/kg/d x pump volume/flow rate) plus dexamethasone for 14 days of a 28-day cycle. The dose-limiting toxicities were diarrhea and neutropenia. The response rate (complete and partial) among all patients who did not undergo cryosurgery was 74%. All patients in the cryosurgery group responded, and seven of the eight cryosurgery patients developed normal positron emission tomography scans after chemotherapy. HAI FUDR had no effect on the metabolism of irinotecan. CONCLUSION: Combination therapy with HAI FUDR and dexamethasone plus systemic irinotecan may be safely administered to patients with unresectable hepatic metastases from colorectal cancer. The MTD has been reached for patients with unresectable disease, and we continue to investigate the MTD for patients who have undergone cryosurgery. Although the main objective of this study was to evaluate the toxicity of the combined regimen, a high response rate (74%) was observed.

Automated, multiplex assay for high-frequency microsatellite instability in colorectal cancer.

PURPOSE: In a series of hereditary nonpolyposis colorectal cancer (HNPCC) patients, we evaluated the sensitivities of the individual microsatellites recommended by the National Cancer Institute (NCI) consensus workshop for detection of high-frequency microsatellite instability (MSI-H). On the basis of this evaluation, we developed a three-marker assay that assigns microsatellite instability (MSI) in a multiplex polymerase chain reaction. METHODS: Individual marker sensitivity was assessed in 18 HNPCC tumors. Multiplex and NCI assays were then assessed in a series of 120 patients with early-onset colon cancer. RESULTS: The sensitivity of microsatellite markers BAT25, BAT26, D2S123, D5S346, and D17S250 for ASI in HNPCC cancers was 100%, 94%, 72%, 50%, and 50%, respectively. The three most accurate markers were combined and optimized in a multiplex assay that assigned MSI-H whenever at least two of three markers revealed ASI. In early-onset colon cancers, the prevalence of MSI-H determined by the multiplex assay and by the NCI assay was 16% and 23%, respectively. The additional MSI-H tumors and patients with MSI-H identified by the NCI assay lacked the traits characteristic of MSI-H seen in tumors and patients identified by the multiplex assay: retention of heterozygosity (NCI additional 22% v multiplex 84%; P =.003), characteristic tumor morphology (0% v 64%; P =.006), and 5-year cancer survival rate (44% v 100%; P =.0003). CONCLUSION: The multiplex assay identifies colon cancers with MSI-H by assessing three highly accurate microsatellite markers. This assay identifies a smaller MSI-H cohort with more homogeneous clinical features and is superior as a marker of favorable prognosis. It merits prospective evaluation as a marker of prognosis and as a screening test for HNPCC.

Inducible microsomal prostaglandin E synthase is overexpressed in colorectal adenomas and cancer.

Recently, an inducible microsomal human prostaglandin E synthase (mPGES) was identified. This enzyme converts the cyclooxygenase (COX) product prostaglandin (PG) H(2) to PGE(2), an eicosanoid that has been linked to carcinogenesis. Increased amounts of PGE(2) have been observed in many tumor types including colorectal adenomas and cancers. To further elucidate the mechanism responsible for increased levels of PGE(2) in colorectal tumors, we determined the amounts of mPGES and COX-2 in 18 paired samples (tumor and adjacent normal) of colorectal cancer. With immunoblot analysis, mPGES was overexpressed in 83% of colorectal cancers. COX-2 was also commonly up-regulated in these tumors; marked differences in the extent of up-regulation of mPGES and COX-2 were observed in individual tumors. Immunohistochemistry revealed increased mPGES immunoreactivity in neoplastic cells in both colorectal adenomas and cancers compared with adjacent normal colonic epithelium. Cell culture was used to investigate the regulation of mPGES and COX-2. Chenodeoxycholate markedly induced COX-2 but not mPGES in colorectal cancer cells. Tumor necrosis factor-alpha induced both mPGES and COX-2, but the time course and magnitude of induction differed. As reported previously for COX-2, overexpressing Ras caused a several-fold increase in mPGES promoter activity. Taken together, our results suggest that overexpression of mPGES in addition to COX-2 contributes to increased amounts of PGE(2) in colorectal adenomas and cancer. The mechanisms controlling the expression of these two enzymes are not identical.

K-ras mutation in adenomas and carcinomas of the ampulla of vater.

The role of K-ras mutations in the progression of tumors of the ampulla of Vater is not well understood. To study the frequency and timing of K-ras mutations in ampullary tumors, areas of invasive carcinoma and adjacent adenomas were microdissected from paraffin blocks from 96 resected tumors. DNA was extracted, PCR amplification of K-ras exon 1 was performed, and PCR products were sequenced. Statistical analysis of K-ras mutations with respect to patient survival and clinicopathological factors was performed using the chi2 test, log-rank test, and Cox proportional hazard model. Thirty-four of 92 ampullary carcinomas (37.0%) and 25 of 46 adenomas (54.3%) had mutations in K-ras exon 1. Twenty-two of 23 (95.7%) adenomas adjacent to carcinomas with K-ras mutations also had K-ras mutations. The only clinicopathological factor significantly associated with K-ras mutation was tumor size >2 cm (P = = 0.035). Patient survival did not correlate with the K-ras mutation status (P = 0.31). We conclude that K-ras mutations are frequent in both adenomas and carcinomas of the ampulla of Vater and appear to occur as an early genetic event. The spectrum of mutations is similar to that observed in colorectal neoplasms, and these do not significantly correlate with patient survival.

Sphincter preservation in rectal cancer. Technical considerations for coloanal anastomosis and J-pouch.

Most patients with midrectal cancer undergo a sphincter-preserving operation using modern bowel stapling techniques. In patients with bulky tumors or unfavorable pelvic anatomy, however, abdominoperineal resection with permanent colostomy may be performed for technical reasons, not based on oncologic clearance needs. In addition, low-lying tumors treated initially with preoperative chemoradiation are often downstaged, increasing the opportunity for restorative procedures. Treatment by total proctectomy and peranal sutured coloanal reconstruction fulfills the need for adequate oncologic clearance and satisfactory bowel function. Sharp pelvic dissection with removal of the entire rectal mesentery, adequate mobilization of the left colon, and precise anastomotic technique are required for optimal results. Creation of a colon J-pouch increases the capacity of the reconstructed rectum and greatly reduces the time required for functional adaptation in the postoperative period. Although irregular evacuation and other minor problems can persist, permanent colostomy is avoided, and patient satisfaction is high. For cancers of the middle and distal rectum, total proctectomy with coloanal reconstruction is an important treatment option that can improve quality of life without compromising cancer treatment.

Sphincter preservation with preoperative radiation therapy and coloanal anastomosis.

PURPOSE: To determine if preoperative radiation therapy allows sphincter preservation in the treatment of rectal cancer. METHODS AND MATERIALS: Thirty patients with the diagnosis of invasive, resectable, primary adenocarcinoma of the rectum limited to the pelvis were enrolled on a Phase I/II trial of preoperative radiation therapy plus low anterior resection/coloanal anastomosis. By preoperative assessment, all patients had invasive tumors (2: T2 28:T3) involving the distal half of the rectum and required an abdominoperineal resection. The median tumor size was 4 cm (range: 1.5-6 cm) and the median distance from the anal verge was 4 cm (range: 3-7 cm). The whole pelvis received 46.8 Gy followed by a 3.60 Gy boost to the primary tumor bed. The median follow-up was 43 months (range: 6-82 months). RESULTS: Of the 29 patients who underwent resection, 3 (10%) had a complete pathologic response and 24 (83%) were able to successfully undergo a low anterior resection/colonanal anastomosis. The incidence of local failure was crude: 17% and 4-year actuarial: 23%. The 4-year actuarial survival was 75%. One patient developed a partial disruption of the anastomosis and two developed rectal stenosis. Analysis of sphincter function using a previously published scale was performed at the time of last follow-up in 22 of the 24 patients who underwent a low anterior resection/coloanal anastomosis. Function was good or excellent in 77%. The median number of bowel movements/day was two (range: 1-6). CONCLUSIONS: This technique may be an alternative to an abdominoperineal resection in selected patients. Continued follow-up is needed to determine if this approach ultimately has similar local control and survival rates as an abdominoperineal resection.

Conservative management of rectal cancer with local excision and postoperative adjuvant therapy.

BACKGROUND: To determine the local control, survival, and functional outcome of local excision plus postoperative therapy for patients with rectal cancer. METHODS: A total of 39 patients underwent a local excision (2 with snare excision of a T1 polyp and 37 with full-thickness local excision) followed by postoperative radiation therapy +/- 5-FU-based chemotherapy. The median follow-up was 41 months, and 11 patients had positive margins. RESULTS: The 5-year actuarial colostomy-free survival was 87% and overall survival was 70%. Crude local failure increased with T stage: 0% T1, 24% T2, and 25% T3. Of the 8 patients (21%) who developed local failure, 5 underwent salvage APR and were locally controlled. Actuarial local failure at 5 years was 31% for T2 disease and 27% for the total patient group. In the 32 patients with an intact sphincter, 94% had good to excellent sphincter function. CONCLUSION: Although local failure in patients with T2 tumors has increased since our prior report, the survival, sphincter function, and local salvage rates are acceptable. Local excision and postoperative therapy remains a reasonable alternative to APR in selected patients.

Sphincter preservation in rectal cancer with preoperative radiation therapy and coloanal anastomosis: long term follow-up.

BACKGROUND: To determine if preoperative radiation therapy allows sphincter preservation in the treatment of rectal cancer. METHODS: Thirty six patients with the diagnosis of invasive, resectable, primary adenocarcinoma of the rectum limited to the pelvis were enrolled on a Phase I/II trial of preoperative radiation therapy plus low anterior resection/coloanal anastomosis. By preoperative assessment, all patients had invasive tumors (5,T2; 31,T3) involving the distal half of the rectum and clinically required an abdominoperineal resection. The median tumor size was 3.8 cm [range: 1.5-7 cm] and the median distance from the anal verge was 4 cm [range: 3-7 cm]. The whole pelvis received 46.80 Gy followed by a 3.60 Gy boost to the primary tumor bed. The median follow-up was 56 months [range: 4-121 months]. RESULTS: Of the 35 patients who underwent resection, 5 (14%) had a complete pathologic response and 27 (77%) were able to successfully undergo a low anterior resection/coloanal anastomosis. The incidence of local failure was crude: 17% and 5-year actuarial: 21%. The 5-year actuarial survival was 64%. Analysis of sphincter function using a previously published scale was performed at the time of last follow-up in the 27 patients who underwent a low anterior resection/coloanal anastomosis. Function was good or excellent in 85%. The median number of bowel movements/day was 2 (range: 0-8). CONCLUSIONS: Our data suggest that preoperative radiation therapy allows sphincter preservation in 77% of selected patients who would otherwise require an abdominoperineal resection, and 85% have good to excellent sphincter function. Given the moderate local failure rate, we now routinely use preoperative combined modality therapy plus postoperative chemotherapy for patients with clinical T3 disease.