What factors influence 10-year survival after curative resection of a colorectal carcinoma?

BACKGROUND: Ten-year survival rates are only rarely reported and frequently include a large proportion of censored data-that is, most of the patients have not survived the 10 years. We therefore selected patients in a prospectively maintained, hospital-based tumor register who had been operated on for colorectal carcinoma (CRC) more than 10 years earlier and who were classified as long-term survivors. METHODS: For 589 consecutive CRC patients who underwent R0 resection in the period 1990-1998, we compared prognosis-relevant characteristics and calculated the survival rate as a function of age, sex, location of the tumor, general state of health, urgency of the operation, and pT and pN class. All patients were observed until their death or until at least 10 years after resection. Patients who died of other causes were censored. Overall survival and relative survival (the latter based on tumor-related death) were assessed. RESULTS: The 10-year survivors were more often female (not significant), younger (p < 0.001), in good general health (p < 0.001), had undergone elective resection (p < 0.001), and had early-stage tumors (p < 0.001). In the univariate analysis emergency operation, impaired general health, invasion beyond the muscularis propria, and lymph-node metastasis were found to reduce relative survival. In the multivariate analysis, location, emergency resection, pT, and pN were found to be statistically independent risk factors. CONCLUSIONS: Long-term freedom from tumor recurrence, like-short-term, is influenced largely by factors that are beneficially influenced by early recognition. The patient's age at resection is immaterial.

Evaluation of the biocompatibility of a new vascular prosthesis coating by detection of prosthesis-specific antibodies.

In recent experimental studies, we could demonstrate the occurrence of antibodies against the prosthesis matrix and coating following implantation of polyester-based vascular grafts. Therefore, this study aimed at evaluating the biocompatibility of a new absorbable polymer coating by detection of antibodies against the coating and the polyester matrix. Two polyester vascular prostheses coated either with the polymer (PP-prosthesis) or with gelatine (PG-prosthesis) were functionally implanted into sheep (n = 22 per group). Blood was drawn on days 1 (pre-OP) and 7, 14, 28, 56, 84, 140 (post-OP). Homogenates from both prostheses (PP-target or PG-target) or from an uncoated prosthesis (P-target) were used as assay targets in a particle-based immunoassay. The antibody binding against the P-target was significantly higher in the PP-group than in the PG-group on days 7-56, but not on days 84 and 140. Within both groups, no significant differences but a significant correlation between the binding against the P-target and the coated target was found. Therefore, the absorbable polymer did not induce a specific humoral immune response. In conclusion, the overall immunogenicity of the polymer-coated graft was comparable to the gelatine-coated graft. The detection of prosthesis-specific antibodies seems to be useful for in vivo biocompatibility testing.

Local tissue reaction and differentiation of the prosthesis-specific antibody response following functional implantation of vascular grafts in pigs.

The study was aimed at investigating the local tissue reactions through a histological examination of beta-1-integrin expression and neointima formation, and humoral immune responses by detection of prosthesis-specific antibodies, after functional implantation of vascular prostheses. In three groups of pigs, the infrarenal aorta was replaced with segments of collagen-impregnated Dacron-prostheses: M-prosthesis--medium primary porosity, double velour layer, crimping; C-prosthesis--low primary porosity, no velour, crimping; T-prosthesis--high primary porosity, no velour, no crimping. For each prosthesis type, one series with four animals was used for examining the tissue reactions, and a second series with eight animals was used to study the antibody response, both until 116 days postoperative. In the first three weeks, the M-prosthesis caused the highest tissue reactions and the highest antipolyester antibodies, but the lowest anticollagen antibodies, whereas the T-prosthesis caused the highest anticollagen antibodies, but the least tissue response and antipolyester antibodies in the early phase. On day 116, the C-prosthesis caused the highest tissue reactions and highest polyester-specific antibodies. These results indicate a possible association between local inflammatory reactions and humoral immune responses, influenced by properties of vascular grafts.

Digital image analysis for morphometric evaluation of tissue response after implanting alloplastic vascular prostheses.

The aim of this study was to examine the suitability of digital image analysis, using the KS400 software system, for the morphometric evaluation of the tissue response after prosthesis implantation in an animal model. Twenty-four female pigs aged 10 weeks were implanted with infrarenal Dacron(R) prostheses for 14, 21, 28, and 116 days. Following the explantation and investigation of the neointima region, the expression of beta-1-integrin, the proliferation rate by means of Ki-67 positive cells, and the intima thickness were evaluated as exemplary parameters of the tissue response after implantation. Frozen tissue sections were immunohistochemically stained and subsequently examined using computer-aided image analysis. A maximum expression of 32.9% was observed for beta-1-integrin 14 days after implantation, gradually declining over time to 9.8% after 116 days. The proliferation rate was found to be 19% on day 14, increasing to 39% on day 21 with a subsequent gradual decline to 5% after 116 days. The intima thickness increased from 189.9 microm on day 14 to 1228.0 microm on day 116. In conclusion, digital image analysis was found to be an efficient and reproducible method for the morphometric evaluation of a peri-prosthetic tissue response.

The impact of the risk factor "age" on the early postoperative results of surgery for colorectal carcinoma and its significance for perioperative management.

The risks and benefits of surgery for colorectal cancer in old patients have not been unequivocally defined. The present investigation was carried out in 309 hospitals as a prospective multicenter study. In the period between 1 January 2000 and 31 December 2001, a total of 19,080 patients were recruited for the study; 16,142 (84.6%) patients were younger than 80 years (<80) and 2932 (15.4%) were 80 years and older (> or =80). Significant differences between the age groups were observed for general postoperative complications (22.3% for <80 years; 33.9% for > or =80). Specific postoperative complications were identical in both groups. Overall, significantly elevated morbidity and mortality rates were found with increasing age (morbidity: 33.9% vs. 43.5%; mortality: 2.6% vs. 8.0%). The distribution of tumor stages revealed a significantly higher percentage of locally advanced tumors in the older age group (stage II: 28.0% vs. 34.4%). In contrast, no increase in metastasizing tumors was found in the older age group (stage IV: 17.4% vs. 14.1%). Logistic regression showed that, in concert with a number of other parameters, age is a significant influencing factor on postoperative morbidity and mortality. The increase in postoperative morbidity and mortality rates associated with aging is a result of the increase in general postoperative complications, in particular, pneumonia and cardiovascular complications. Age as such does not represent a contraindication for surgical treatment. The short-term outcome and quality of life are of overriding importance for the geriatric patient.

Vascular graft infections: in vitro and in vivo investigations of a new vascular graft with long-term protection.

We investigated a polyester vascular prosthesis (PET) coated with elemental silver (SC). Measurement of silver release over a period of 52 weeks by means of inductively coupled plasma atomic emission spectrometry of PET with (PET-G) and without (PET-N) gelatine impregnation revealed a silver release on the first day of 1.2 +/- 0.2 microg (PET-N) and 1.2 +/- 0.1 microg (PET-G) (calculated for 1 g of prosthesis); from the 90th day onward, it was between 0.22 +/- 0.14 microg (PET-N) and 0.18 +/- 0.12 microg (PET-G) per day. The prostheses were incubated with Staphylococcus aureus (S.a.), Staphylococcus epidermidis (S.e.), or Escherichia coli (E.c.) to investigate in vitro antibacterial efficacy. After 6 h of incubation, no colony-forming units were to be seen for any of the bacterial suspensions for PET with SC (p < 0.001). To investigate in vivo antibacterial efficacy, PET-G rings with and without SC contaminated with S.a., S.e., or E.c. were implanted in 18 albino rabbits and examined 7 days after agar culture for 48 h. The silver coating was associated with a significant reduction in bacterial growth (S.a., p = 0.001; S.e., p < 0.005; E.c., p < 0.001). The silver-coated prosthesis, with and without gelatine impregnation, had a significantly antibacterial effect with continuous release of silver.

Comparison of the ovine and porcine animal models for biocompatibility testing of vascular prostheses.

OBJECTIVE: Evaluation of the pig and sheep models for biocompatibility investigations of vascular prostheses (VP). DESIGN: Comparative analysis of animal experimental investigations involving two different animal models. MATERIALS AND METHODS: Commercially available polyester vascular prostheses (PET-VP) were implanted into two different animal models (infrarenal porcine aorta and ovine carotid artery). The costs, surgical handling, patency rate, and healing on the basis of macroscopic, microscopic, and immunohistochemical criteria were analyzed over a period of 3 months. RESULTS: Handling and operating times (63 +/- 10 versus 76 +/- 16 min; P = 0.125) did not differ significantly. The cost of the two animal models was comparable. Integration of the VP was complete in the sheep model, but varied in the pig model (two complete, four incomplete). Complete endothelialization of all VPs was observed in the pig, which contrasted with the sheep with complete (circular) endothelialization only in the region of the anastomosis. The thickness of neointima in the region of the anastomosis differed insignificantly; immunohistochemically, only periprosthetic Ki67 was significantly reduced (28.7 +/- 9.9 versus 6 +/- 0.9%; P = 0.002) in the sheep. CONCLUSIONS: In the porcine model, extremely good endothelialization of the VP was observed, with formation of a rapid neointimal hyperplasia. The ovine model was characterized by the fact that postoperative follow-up investigations were easy to perform. Complete endothelialization was not observed.

The significance of Meckel's diverticulum in appendicitis--a retrospective analysis of 233 cases.

Conflicting reports are found in the literature concerning whether to remove an incidentally discovered Meckel's diverticulum (MD). Between 1.1.1974 and 31.12.2000, at a single center, the perioperative data associated with appendectomy (AE) were recorded consecutively and analyzed retrospectively. All patients in whom an MD was discovered during an AE were included in the study. The clinical presentation, postoperative course, and follow-up in all MDs left in place were analyzed. During the course of 7927 AE, 233 MD (2.9%) were detected. Of these 80.7% (n = 188) were removed and 19.3% (n = 45) were left untouched. In 9% (n = 21) of all detected diverticula pathological changes were found. Ectopic tissue was seen in 12.2% (n = 23) of the MDs removed. The postoperative complication rates did not differ significantly between patients in whom the MD was removed (9.5%; n = 18) and those in whom it was not (17.7%; n = 8); in the latter group the appendicitis was of the more acute type (gangrenous or perforated) (24.4% vs. 4.3%). In 18 patients (40.0%) with non-removed MDs, a follow-up period of 14.1 5.8 years was achieved. Complications associated with a non-removed MD were not observed. If during the course of an AE a MD is detected, the present data, as well as those in the literature, suggest that an individualized approach should be taken. Meckel's diverticulum with obvious pathology should always be removed. In cases of gangrenous or perforated appendicitis, an incidentally discovered MD should be left in place, whereas in an only mildly inflamed appendix it should be removed.

Characteristics of titanium-coated polyester prostheses in the animal model.

Commercially available polyester vascular prostheses (n = 6) in the control group (CG) and titanium-coated vascular prostheses (TP; n = 7) were interposed within the infrarenal aorta of pigs. The respective healing characteristics and patency rates were compared after 3 months. For evaluation purposes, macroscopic, histological, and immunohistochemical criteria were applied. The macroscopic evaluation revealed complete healing of the TP in comparison with the CG. Extraluminal inspection revealed prominent firm cicatricial tissue in the prosthesis bed of the TP group. All TP were occluded. In the CG, occlusion of the prostheses occurred in n = 1 (16 %). On average, neointimal hyperplasia (NIH) in the proximal part of the anastomosis was not significantly different to the CG. The extraluminal proliferation index (Ki67) was reduced in the TP group (p = 0.002). The immunohistochemical analysis of intraluminal changes revealed no significant differences between CG and TP. All of the titanium-coated polyester vascular prostheses were found to be occluded. The additional coating of polyester prostheses with titanium would not appear to be of any particular benefit.

Ninety-four appendectomies for suspected acute appendicitis during pregnancy.

Acute appendicitis during pregnancy is a rare event, and large numbers of cases reported in the literature stem entirely from data stored in national registers. Between 1974 and 2000 relevant perioperative data on the treatment of appendicitis were collected consecutively and analyzed retrospectively. Surgical and obstetric data relating to the medical history, the clinical, intraoperative, and histologic findings, and the course of the pregnancy were recorded. Altogether, 9793 appendectomies were performed, 94 of which were in pregnant women (24.5% during the first trimester, 51% during the second trimester, and 24.5% during the third trimester). This represents 0.2% of the 46,960 deliveries during the period under observation. Fifty percent of the case histories during the second trimester were atypical. The overall perforation rate was 14.9%; it was 8.7%, 12.5%, and 26.1% during the three trimesters, respectively. Maternal mortality was 0%; the combined miscarriage/abortion rate was 8.5% (n = 8); and infant mortality was 3.2% (n = 3). The postoperative spontaneous abortion rate was 13.0% and the additional therapeutic/requested abortion rate 21.7% during the first trimester. In view of the elevated postoperative abortion rate and the facility of the clinical diagnosis during the first trimester, the indication for invasive diagnostic measures and surgery requires careful consideration. During the second and third trimesters the difficulty of establishing a clinical diagnosis makes it necessary to undertake exploratory surgery early.