Staging of rectal carcinoma with transrectal ultrasonography.

BACKGROUND AND AIMS: Transrectal ultrasonography (TRUS) has proven useful for loco-regional staging of rectal carcinoma in specialised centres, but the investigation is not widely used. The aim of this study was to audit the introduction of TRUS performed by surgeons without previous experience with ultrasonography. MATERIAL AND METHODS: All patients admitted with rectal carcinoma in the period 1996-2002 entered this prospective, comparative study. TRUS with a stiff endorectal probe was performed preoperatively in 118 consecutive patients, 91 of whom subsequently had rectal resection without preoperative radiotherapy (PRT), and seven who had rectal resection after PRT. Twenty patients did not have resection. The main outcome measures was the feasibility of TRUS in staging of rectal cancer, and the accuracy of T- and N-staging, comparing TRUS with the histopathological examination of resected specimens. RESULTS: TRUS was successful in 81/91 patients who underwent rectal resection without PRT. The accuracy of T-staging was 74% overall; 40% in five pT1 tumours, 81% in 26 pT2 tumours, 80% in 45 pT3 tumours and 25% in four pT4-tumours. With regard to perirectal tissue invasion, the sensitivity and specificity of TRUS was 82% and 84%, respectively, and the positive and negative predictive values were 89% and 71%, respectively. The accuracy of TRUS for N-staging was 65%. The sensitivity for detection of lymph node metastases was 41% and the specificity 68%. TRUS was unsuccessful in 21/118 patients, in 12/98 who had rectal resection, and in 9/ 20 who did not have resection, because of stenosis or high location of the tumour precluding correct placing of the probe. CONCLUSIONS: TRUS is often unsuccessful in patients with advanced tumours, especially when the tumour is located in the upper rectum. The predictive values for perirectal tumour invasion were acceptable, but the sensitivity for detection of lymph node metastases was low. These results were obtained by surgeons without previous experience with ultrasonographic examinations.

Genetic and protein markers related to in situ growth and multiplicity in small sporadic colorectal adenomas.

BACKGROUND: Some early genetic events in the development of colorectal adenomas are known, but their relationship to in vivo growth characteristics is uncertain. This study compared in situ size changes and other clinicopathological variables with selected genetic and protein markers. METHODS: 56 adenomas (< or = 10 mm) from 39 patients were analysed for APC, CTNNB1 and K-ras mutations, allelic imbalance on 1p and 18q, microsatellite instability and immunohistochemical expression of HLA-DR, BAX, BCL-2 and Ki-67. For 42 of the adenomas, in situ growth was measured over 3 years. The total number of polyps in each patient was recorded. RESULTS: K-ras was mutated in 8/56 adenomas. None of the regressing adenomas revealed such mutations, compared to 20% in those that maintained or increased their size. Multivariate linear regression analysis showed that tumour growth was higher in females compared to males, and was even higher in the presence of a K-ras mutation. APC mutations were found in 37/56 adenomas. CTNNB1 mutations were found in 2/19 adenomas without APC mutation. Deletions of 1p were found in 12/56 adenomas and, seemingly, most frequent in patients with few tumours. The most frequently expressed protein was BAX (33/41), but neither this nor the other proteins showed associations with an in situ growth pattern. CONCLUSION: The multivariate linear regression model showed that patient gender and the presence of K-ras mutation had significant effects on tumour growth. The lack of the proliferative stimulus resulting from a K-ras mutation may contribute to the process of adenoma regression.

APC and CTNNB1 mutations in a large series of sporadic colorectal carcinomas stratified by the microsatellite instability status.

BACKGROUND: Adenomatous polyposis coli (APC) and beta-catenin (encoded by CTNNB1) are important components in the WNT signalling pathway, a pathway altered in nearly all colorectal tumours. Conflicting results are reported on whether APC mutations are less common in tumours with a high degree of microsatellite instability (MSI-H) than in microsatellite stable (MSS) ones, and whether mutations in the regulatory domain of CTNNB1 substitute for APC mutations in the MSI-H tumours. METHODS: A consecutive series of 218 primary colorectal carcinomas, stratified by MSI status, were analysed for mutations in the APC gene (by the protein truncation test) and in the CTNNB1 gene (by single-strand conformation polymorphism). RESULTS: APC mutations detected in 66% of the patients were significantly more frequent in the MSS and MSI-L (low) tumours than in the MSI-H tumour group (P < 0.001). The MSI-H tumours tended to have more frameshift mutations than the MSS/MSI-L tumours. The majority of the APC mutations were located in the mutation cluster region (MCR). Patients that had lost all beta-catenin binding sites of the APC gene showed a shorter survival time than patients who retained some or all of these binding sites (P = 0.045). Two mutations were found in the CTNNB1 gene, but neither of them was located in the regulatory domain in exon 3. CONCLUSION: This study confirms that APC mutations are less frequent in MSI-H tumours than in MSS and MSI-L tumours. However, CTNNB1 mutations do not substitute for APC mutations in MSI-H tumours in these Norwegian patients.

Strong HLA-DR expression in microsatellite stable carcinomas of the large bowel is associated with good prognosis.

Progression of colorectal cancer may follow either of two main genetic routes: the chromosome- or microsatellite-instability pathways. Association between the patients' prognosis and microsatellite instability has been questioned. Improved survival has previously been found in patients with expression of HLA-DR antigens on their tumour cells. In this study, the expression of HLA-DR antigen was investigated by immunohistochemistry in 357 large bowel carcinomas stratified by microsatellite instability status. Sixteen per cent of the tumours showed strong HLA-DR expression and 35% had weak DR expression. We confirmed that patients with strong positive HLA-DR staining had improved survival (P<0.001) compared to patients with no HLA-DR expression. Strong epithelial HLA-DR staining was significantly associated with high level of microsatellite instability (P<0.001). In the subgroup of tumours with characteristics typical of the chromosomal instability phenotype, i.e. in microsatellite-stable tumours, the patients positive for the HLA-DR determinants showed better survival than those without HLA-DR expression. The protective effect of HLA-DR expression on survival was confirmed by multivariate analysis, both in the whole patient group and in the microsatellite-stable/microsatellite instability-low group. This might be explained by enhanced T-cell mediated anti-tumour immune responses against tumour cells in the HLA-DR positive tumours. The finding of better patient survival in the subgroup of strong HLA-DR positive microsatellite-stable tumours may have clinical implications for these patients.

Kirsten ras mutations in patients with colorectal cancer: the 'RASCAL II' study.

Researchers worldwide with information about the Kirsten ras (Ki-ras) tumour genotype and outcome of patients with colorectal cancer were invited to provide that data in a schematized format for inclusion in a collaborative database called RASCAL (The Kirsten ras in-colorectal-cancer collaborative group). Our results from 2721 such patients have been presented previously and for the first time in any common cancer, showed conclusively that different gene mutations have different impacts on outcome, even when the mutations occur at the same site on the genome. To explore the effect of Ki-ras mutations at different stages of colorectal cancer, more patients were recruited to the database, which was reanalysed when information on 4268 patients from 42 centres in 21 countries had been entered. After predetermined exclusion criteria were applied, data on 3439 patients were entered into a multivariate analysis. This found that of the 12 possible mutations on codons 12 and 13 of Kirsten ras, only one mutation on codon 12, glycine to valine, found in 8.6% of all patients, had a statistically significant impact on failure-free survival (P = 0.004, HR 1.3) and overall survival (P = 0.008, HR 1.29). This mutation appeared to have a greater impact on outcome in Dukes' C cancers (failure-free survival, P = 0.008, HR 1.5; overall survival P = 0.02, HR 1.45) than in Dukes' B tumours (failure-free survival, P = 0.46, HR 1.12; overall survival P = 0.36, HR 1.15). Ki-ras mutations may occur early in the development of pre-cancerous adenomas in the colon and rectum. However, this collaborative study suggests that not only is the presence of a codon 12 glycine to valine mutation important for cancer progression but also that it may predispose to more aggressive biological behaviour in patients with advanced colorectal cancer.

Villous, hypermucinous mucosa in long standing ulcerative colitis shows high frequency of K-ras mutations.

BACKGROUND: K-ras mutation is one of the first genetic alterations in classical colorectal carcinogenesis. AIMS: To investigate the role of K-ras mutations in carcinogenesis, in long standing ulcerative colitis. METHODS: A total of 161 microdissected and 100 DNA samples from 13 patients were analysed for K-ras codons 12 and 13 mutations by means of a combination of enriched polymerase chain reaction amplification and temporal temperature gradient electrophoresis. RESULTS: K-ras mutations were found in 21/161 (13%) microdissected samples in 7/13 large bowels (16 and five in codons 12 and 13, respectively), and in 10/100 (10%) mucosal DNA samples (six and four, respectively). One of four patients with six adenocarcinomas had a K-ras mutation in a carcinoma, as well as one of two patients with large dysplasia associated lesion or mass (DALM). Eight of 13 (61%) areas with villous architecture and large, distended goblet cells, had a K-ras mutation, which was significantly more frequent than in low grade dysplasia (one of 23, 4%) but did not reach significance versus high grade dysplasia (four of 14, 28.5%). K-ras mutations were found in one of 20 (5%) flat lesions indefinite for dysplasia, two of 14 (14%) in non-villous, hypermucinous mucosa, and in one of 57 flat areas negative for dysplasia. CONCLUSION: The highest K-ras mutation frequency was found in villous, hypermucinous mucosa. We suggest that this entity should be investigated further as a potential risk lesion for cancer development. It may represent a pathway directly from non-classical dysplasia to cancer, not previously described.

Germline and somatic mutations in exon 15 of the APC gene and K-ras mutations in duodenal adenomas in patients with familial adenomatous polyposis.

BACKGROUND: In sporadic colorectal adenomas mutations in the adenomatous polyposis gene (APC) are among the first gene aberrations to appear. In familial adenomatous polyposis (FAP) the patients already have a germline mutation in the APC gene. To investigate the natural history of duodenal adenomas in FAP patients, we examined germline and somatic mutations of the APC gene and K-ras mutations in these lesions. METHODS: Frozen sections from 54 duodenal polyps from 31 FAP patients were used to histologically verify the presence of adenomatous growth in the mucosa; the rest of each biopsy specimen was processed for DNA extraction. APC exon 15 was investigated with the protein truncation test (PTT), using four overlapping polymerase chain reaction (PCR) fragments, and samples showing an APC mutation were thereafter sequenced. The adenomas were examined for K-ras mutations by use of a combination of the 'enriched PCR method' and temporal temperature gradient electrophoresis. RESULTS: APC germline mutations in exon 15 were found in 19 of 31 (61%) patients, whereas somatic mutations were localized to 12 of 54 (22%) duodenal adenomas. In seven adenomas both the germline and the somatic mutations were found, whereas five small adenomas showed somatic mutations only. There was no tendency for more mutations to be detected in large and severely dysplastic adenomas compared with small and mildly dysplastic ones. K-ras mutations were found in four (7%) duodenal adenomas. CONCLUSIONS: The low rate of somatic APC and K-ras mutations in duodenal adenomas may indicate another neoplastic pathway than in FAP adenomas of the large bowel, or that a modifier gene is cosegregating with the disease.

K-ras mutations and prognosis in large-bowel carcinomas.

BACKGROUND: Colorectal carcinogenesis is regarded as a multistep process involving several genetic alterations, with mutation in the K-ras gene in about half of the tumours. We aimed at clarifying the role of this genetic alteration related to survival and clinicopathologic variables. METHODS: One hundred large-bowel carcinomas operated on between 1978 and 1982 were studied for the presence of point mutations in codons 12 and 13 of the K-ras gene, using enriched polymerase chain reaction amplification, restriction fragment length polymorphism analysis, and direct sequencing. RESULTS: Forty mutations were found (40%): 31 in codon 12 and 9 in codon 13, 7 different types. There was no relationship between tumours with and without K-ras mutations with regard to Dukes' stages, age or sex of the patient, tumour localization, histologic grade, DNA ploidy pattern, HLA-DR staining pattern, or survival. Samples from 5 different localizations in 7 carcinomas showed identical K-ras mutation pattern, as did 19 recurrences/ metastases originating from 11 carcinomas. CONCLUSIONS: When present, the primary tumour shows homogeneous distribution of K-ras mutation, and the mutation follows the carcinoma in the secondary deposit, regardless of lymphogenous or hematogenous spread. The presence of K-ras mutation does not seem to have prognostic significance for the patient, and the precise nucleotide change is furthermore not predictive of tumour behaviour.

K-ras mutations and HLA-DR expression in large bowel adenomas.

A total of 72 sporadic colorectal adenomas in 56 patients were studied for the presence of point mutations in codons 12 and 13 of the K-ras gene and for HLA-DR antigen expression related to clinicopathological variables. Forty K-ras mutations in 39 adenomas were found (54%): 31 (77%) in codon 12 and nine (23%) in codon 13. There was a strong relationship between the incidence of K-ras mutations and adenoma type, degree of dysplasia and sex. The highest frequency of K-ras mutations was seen in large adenomas of the villous type with high-grade dysplasia. Fourteen out of 15 adenomas obtained from 14 women above 65 years of age carried mutations. HLA-DR positivity was found in 38% of the adenomas, large tumours and those with high-grade dysplasia having the strongest staining. Coexpression of K-ras mutations and HLA-DR was found significantly more frequently in large and highly dysplastic adenomas, although two-way analysis of variance showing size and grade of dysplasia to be the most important variable. None of the adenomas with low-grade dysplasia showed both K-ras mutation and HLA-DR positivity (P = 0.004). K-ras mutation is recognised as an early event in colorectal carcinogenesis. The mutation might give rise to peptides that may be presented on the tumour cell surface by class II molecules, and thereby induce immune responses against neoplastic cells.

Characterization of 'winners' to enoxaparin in the prevention of postoperative venous thromboembolism in digestive surgery.

BACKGROUND: A total of 826 patients were included in three 'play-the-winner' studies to investigate the safety of prophylaxis against venous thromboembolism in digestive surgery. To characterize patients benefiting from prophylaxis with low-molecular heparin, the 445 patients allocated to enoxaparin were investigated. METHODS: A training set consisting of 292 patients from 2 of the studies was analysed by using a linear discriminant model. The reliability of the results was verified on a test set consisting of 153 patients from the third study. RESULTS: A typical 'winner' was a young patient, preferably female, with serum bilirubin in the lower normal range, combined with body temperature, serum sodium, creatinine, and albumin in the upper normal ranges. By using the discriminant function on the test set, 81.7% of the 'winners' and 21.1% of the "losers' were correctly classified. CONCLUSION: The discriminant function for characterization of winners to enoxaparin was found adequate. No rule was acceptable for characterization of losers.

Safety of enoxaparin and dextran-70 in the prevention of venous thromboembolism in digestive surgery. A play-the-winner-designed study.

A total of 327 patients were included in a play-the-winner (PTW)-designed study comparing the safety of prophylaxis with enoxaparin and dextran-70 in patients undergoing digestive surgery. In a PTW-designed study the treatment of any next patient will depend on the outcome of the previous one. If successful, the next patient will receive the same treatment. Excessive bleeding, on the basis of specified criteria, severe adverse effects, or occurrence of clinically detected venous thromboembolism was classified as failure. The PTW design allocates most patients to the superior treatment. In this study 200 patients were given enoxaparin and 127 dextran-70. The success rate was 83% in the enoxaparin group and 74.8% in the dextran-70 group (p = 0.05). The survival analysis of 'Number of patients before change in treatment' shows a significant difference in favour of enoxaparin (p = 0.05). Enoxaparin seems to be superior to dextran-70 as a prophylaxis in digestive surgery. The PTW model is a suitable design in such studies.

Gastric banding for morbid obesity: five years follow-up.

This paper reports on a five year follow-up of 174 morbidly obese patients (132 women) with gastric banding performed between 1981 and 1985. Mean preoperative weight was 122.6 +/- 1.4 kg (s.e.m.) (body mass index (BMI) = 41.8 +/- 0.4 kg/m2) and mean overweight was 73.2 +/- 1.6%. After rapid weight loss during the first six months weight levelled off reaching a nadir at 12-18 months. At 12 months mean weight loss was 36.5 +/- 1.2 kg (BMI = 29.1 +/- 0.4 kg/m2). At 60 months BMI had increased to 32.3 +/- 0.6 kg/m2 (P < 0.05 vs. 12 and 24 months). Mean excess weight at 60 months was 33.5 +/- 2.4% with 47.5% of patients maintaining less than 30% overweight. There were no differences in relative weight loss between men and women and no differences between stomal diameter of 12 or 15 mm 60 months after the operation. Early post-operative complications occurred in 25 patients (14.4%), four of whom required reoperation. Three of these re-operations were for perforations, one of which was fatal. Forty-eight patients (28%) had altogether 60 late complications requiring 26 reoperations (14.9%). There has been a total of four deaths (one clearly unrelated, one unknown) in the series. We conclude that gastric banding is a simple and safe gastric restrictive operation that is effective in about 50% of patients weighing between 90-181 kg (BMI 33-69 kg/m2).

Pulmonary function and energy expenditure after marked weight loss in obese women: observations before and one year after gastric banding.

Pulmonary function and pulmonary gas exchange at rest, and during and after a standard exercise load of 500 kpm in 1 min on bicycle ergometer were studied in 34 women with severe, uncomplicated obesity, aged 37.8 (20-59) years, before and 1 year after gastric banding, resulting in a weight loss from 113.2 (84-156) to 81.7 (60-110) kg. Following the weight loss, TLC and VC rose from 93 and 94 per cent of expected to 98 and 101 per cent, respectively. FRC, ERV and FRC/TLC rose more markedly from 77, 64 and 83 per cent to 98, 109 and 99 per cent. IC fell from 108 to 99 per cent. RV and RV/TLV remained unchanged. FEV1.0 rose from 97 to 103 per cent, while MVV rose from 102 to 112 per cent, i.e. above normal. TLCO and PaCO2 remained unchanged, at 90 and 95 per cent, whereas PaO2 rose from 86 to 91 per cent. Resting O2 intake (VO2) decreased from 147 to 115 per cent of the expected for normal weight women, while VO2/BSA decreased from 113 to 99 per cent, the changes being greater than expected from commonly used formulas for prediction of metabolic rate. O2 cost of work (EO2) decreased from 142 to 105 per cent. Resting ventilation (V) declined from 136 to 113 per cent, while ventilatory cost of work (EV) decreased from 142 to 105 per cent. CO2 recovery time after work (CO2RT) decreased from 121 to 100 per cent, while the ratios CO2RT to EO2 and to extra CO2 output of work (ECO2) rose slightly. Thus, the loss of weight led to increased filling of the lungs, improved dynamic function, reduced ventilation/perfusion disturbances and greater than expected reduction of energy expenditure, both at rest and exercise. In the obese state there was no evidence of alveolar hypoventilation or impaired ventilatory control. The beneficial effect of weight reduction on the exertional dyspnea included a combination of marked reduction of ventilatory demands and moderate rise in ventilatory capacity.

Gastric banding for morbid obesity: early results.

During the years 1981-85, 163 patients were treated with gastric banding for morbid obesity. Mean preoperative body weight (+/- s.e.m.) was 121.3 kg +/- 1.4, and mean overweight was 71.5% +/- 1.6 according to Broca's formula. Twenty-four patients had postoperative complications during the first 30 days, mostly minor. Four required reoperation and one of these died. Seventeen patients had late complications, six persistent vomiting necessitating reoperation, eight incisional hernia and three penetration of gastric wall by band. The weight loss was rapid during the first 6 months, and thereafter levelled off. After 2 years the weight loss was 33.4 kg +/- 2.4, corresponding to a mean weight loss of 27.6 percent +/- 1.9 of preoperative weight. There was no significant difference in weight loss expressed as a percentage of preoperative weight between patients operated with an outlet of 12 mm (45 patients) or 15 mm (118 patients), nor between males (37 patients) or females (126 patients). We conclude that our technique of gastric banding seems to be a relatively safe and reliable surgical treatment for morbid obesity. But our follow-up period has been limited to 2 years or less, and a longer follow-up is necessary before the method can be fully evaluated.