Lymph node evaluation and survival in colorectal cancer: review of population-based, prospective studies.

AIM: The total number of lymph nodes retrieved, the number of positive nodes, and/or their ratio are used to evaluate the degree of progression of colorectal cancer. The aim of the present study is to review the relevant literature in order to improve lymph node evaluation and the quality of clinical practice. MATERIALS AND METHODS: The English language literature on large, population-based, prospective clinical studies of the evaluation of lymph nodes in colorectal cancer was reviewed. This review focuses on the lymph node harvest (LNH) and the lymph node ratio (LNR), and the survival was also assessed. RESULTS: The LNH was influenced by patient age, tumor size, Dukes' stage, preoperative radiotherapy, operative urgency, specimen length, pathology template, and academic status of the hospital. Many prospective studies demonstrated a significant correlation between high LNH and increased survival. LNR is an independent prognostic indicator for stage III colorectal cancer. However, there were many different cut-off values allowing for the optimal separation of subgroups according to survival. CONCLUSION: To improve lymph node evaluation and the quality of clinical practice, daily collaboration between surgeons and pathologists is important. Scientific evidence for reasonable and practical LNH and LNR values should be identified based on large, well-controlled, prospective studies.

Prognostic impact of lymphatic invasion of colorectal cancer: a single-center analysis of 1,616 patients over 24 years.

BACKGROUND: The degree of lymph node metastasis represents an important prognostic factor for cancer. Lymphovascular invasion is a traditional tool for estimating the aggressiveness of colorectal cancer. AIM: To determine correlations between lymphatic invasion and lymph node metastasis or disease stage, and clarify the prognostic impact of lymphatic invasion. PATIENTS AND METHODS: Patients (N=1,616) who underwent curative resection of primary colorectal adenocarcinoma at the Kurume University Hospital were included. Lymphatic invasion was calculated as an average and the degree was also determined (Ly0-3). Clinicopathological factors including lymphatic invasion were assessed by uni- and multivariate analyses to determine factors affecting survival. Survival was compared between different degrees of lymphatic invasion and lymph node metastasis. RESULTS: Lymphatic invasion was absent (Ly0) in 806 patients (50%), and lymph node metastasis was absent (N0) in 1,085 patients (67%). Ninety-one percent of N0 patients were Ly0-1, 72% of N1 were Ly0-1, and 54% of N2 were Ly2-3. All patients with stage 0 disease (100%) were Ly0, 95% of stage I were Ly0-1, 46% of stage II were Ly1-2, and 36% of stage III were Ly2-3. Five- and 10-year survival rates were 83% and 68% in Ly0, 73% and 56% in Ly1, 66% and 49% in Ly2, 63% and 48% in Ly3, 81% and 67% in N0, 69% and 57% in N1, and 60% and 52% in N2, respectively (p<0.0001 each). CONCLUSION: Lymphatic invasion in colorectal cancer correlates well with the status of lymph node metastasis and disease stage, representing an independent prognostic factor after curative resection. Lymphatic invasion can be used for evaluating tumor aggressiveness and estimating patient survival, irrespective of the actual number of positive lymph nodes found.

Prognostic significance of isolated tumor cells in patients with colorectal cancer in recent 10-year studies.

Circulating tumor cells (CTCs) that detach from the primary tumor and move into the circulation are detected in patients with metastatic cancer. The discovery of such cancer cells has been used as a predictor of recurrence and prognosis, although a consensus regarding such applications has not been reached. Peritoneal cytology may be used for identifying high risk of recurrence or mortality, whereas the intraoperative presence of tumor cells in drainage veins, bone marrow, or the liver is not always useful for evaluating the prognosis. The reported positive rate for tumor cells in the peripheral blood of patients with colorectal cancer, including metastasis, has varied from 10 to 80%; however, numerous studies have demonstrated significant differences in the recurrence and mortality rates between patients with and without isolated tumor cells (ITCs) in the peripheral blood. However, the clinical significance of CTCs as an absolute prognostic factor has not been elucidated, since the measurement methodologies and/or the number of cases differed between the studies. Future prospective studies including larger patient populations may elucidate the utility of routine detection of ITCs in daily practice.

Clinicopathological features of hepatocellular carcinoma evaluated by vascular endothelial growth factor expression.

AIM: To evaluate the significance of the expression of vascular endothelial growth factor (VEGF), its correlation with clinicopathological variables were studied in the tissue of hepatocellular carcinoma (HCC) and surrounding liver. METHODS: In 56 samples (tumor and non-tumor liver tissue) collected from 28 patients, VEGF expression was examined by immunohistochemistry and western blot analysis. RESULTS: The value of VEGF expression by western blotting was correlated with immunohistochemical staining grade. In tumor tissue, the value of VEGF expression correlated with tumor size (P = 0.034), á-fetoprotein (P = 0.036) and protein induced by vitamin K absence-II by simple regression, and histological grade (P = 0.0132) by the unpaired t-test. The level of VEGF expression in non-tumor liver was found to correlate with the value of serum albumin (P = 0.008), cholinesterase (P = 0.012) and prothrombin activity (P = 0.046). The frequency of simple nodular type in gross appearance decreased in cases with high tumor/non-tumor (T/N) ratio (P = 0.022), and the degree of portal vein invasion progressed with an increase in the T/N ratio (P = 0.008). The T/N ratio was significantly higher in early recurrence cases (P = 0.0081). CONCLUSION: This study on the expression of VEGF might be useful to estimate the liver condition and the clinicopathological features of HCC.

Development of gastric tumors in Apc(Min/+) mice by the activation of the beta-catenin/Tcf signaling pathway.

Although several lines of evidence suggest the involvement of the Wnt pathway in the development of gastric cancers, the functional significance of the pathway in gastric carcinogenesis is still poorly defined. To examine the role of the Apc/beta-catenin signaling pathway in the development of gastric cancers, we investigated the gastric mucosa of the Apc(Min/+) mouse, which is a murine model for familial adenomatous polyposis, carrying a germ-line mutation at codon 850 of Apc. We found that aged Apc(Min/+) mice spontaneously develop multiple tumors in the stomach, which are accompanied by loss of heterozygosity of Apc. Such tumors consisted of adenomatous glands with strong nuclear accumulation of beta-catenin. Even a single adenomatous gland already showed nuclear accumulation of beta-catenin, suggesting that Apc/beta-catenin pathway is an initiating event in gastric tumorigenesis in Apc(Min/+) mice. Myc and cyclin D1 expressions, which are transcriptional targets of beta-catenin/Tcf, increased in the adenomatous lesions. Furthermore, beta-catenin/Tcf reporter transgenic mice with Apc(Min) allele showed higher levels of the transcriptional activity of beta-catenin/Tcf in the gastric tumors. We also treated Apc(Min/+) and wild-type mice with N-methyl-N-nitrosourea (MNU), an alkylating agent that induces adenomas and adenocarcinomas in the stomach. Consequently, MNU-treated Apc(Min/+) mice significantly enhanced the tumor development in comparison with Apc(Min/+) mice or MNU-treated wild-type mice. Several gastric tumors in MNU-treated Apc(Min/+) mice showed invasion into the submucosal layer. These results indicate that the Apc/beta-catenin pathway may play an important role in at least subset of gastric carcinomas. In addition, Apc(Min/+) mice combined with MNU could be a useful short-term model to investigate multistage carcinogenesis in the stomach.

Depletion of CD4+CD25+ regulatory T cells enhances interleukin-2-induced antitumor immunity in a mouse model of colon adenocarcinoma.

Interleukin 2 (IL)-2 induces antitumor immunity and clinical responses in melanoma and renal cell carcinoma. However, IL-2 also increases the number of CD4(+)CD25(+) regulatory T (Treg) cells that suppress antitumor immune responses. The aim of the present study was to elucidate the effect of depletion of Treg cells on IL-2-induced antitumor immunity. IL-2-transfected mouse colon adenocarcinoma (MC38/IL-2) cells were implanted subcutaneously or intrahepatically into male C57BL/6 mice, and tumor growth and the proportion of tumor-infiltrating lymphocytes with Treg-cell depletion in response to treatment with anti-CD25 monoclonal antibody (PC61) were determined. In mice treated with phosphate-buffered saline, 40-60% of MC38/IL-2 tumors were rejected. In contrast, all MC38/IL-2 tumors were rejected in mice treated with PC61. The number of tumor-infiltrating CD8(+) T cells in mice treated with PC61 was approximately twice that in mice treated with PBS. The numbers of tumor-infiltrating CD4(+) and natural killer cells were also increased significantly. To test the antimetastatic effects of IL-2 treatment in combination with Treg-cell depletion, human recombinant IL-2 (rIL-2) and PC61 were administered to mice implanted with MC38/mock cells in the spleen, and hepatic metastasis was investigated. The average liver weight in mice treated with rIL-2 plus PC61 was 1.04 +/- 0.03 g, less than that in mice treated with rIL-2 (2.04 +/- 0.51 g) or PC61 alone (1.81 +/- 0.38 g). We conclude that IL-2-induced antitumor immunity is enhanced by Treg-cell depletion and is due to expansion of the tumor-infiltrating cytotoxic CD8(+) T-cell population.

Expression of vascular endothelial growth factor receptors is closely related to the histological grade of hepatocellular carcinoma.

Angiogenesis is important for tumor growth, and is regulated by angiogenetic factors such as vascular endothelial growth factor (VEGF). In the present study, we investigated whether or not expression of VEGF receptors (VEGFRs) is related to the proliferation of tumor cells in hepatocellular carcinoma (HCC). We simultaneously stained proliferation marker Ki-67 antigen and either VEGFR1 (Flt-1) or VEGFR2 (Flk-1) on paraffin-embedded tissue sections from 50 cases of surgically resected human HCC. Based on the staining pattern of VEGFRs, we classified the cases into 4 categories; receptor double-negative, Flt-1 single-positive, Flk-1 single-positive, receptor double-positive. Interestingly, the Ki-67 index was significantly lower in receptor double-negative cases in comparison to that in either Flt-1 single-positive or Flk-1 single-positive cases (P = 0.0491, P = 0.0196, respectively). Moreover, the index was also significantly lower in receptor double-positive cases in comparison to either Flt-1 single-positive or Flk-1 single-positive cases (P = 0.0026, P < 0.0001, respectively). We further investigated 35 cases showing a Ki67 index > 10% to determine the expression of VEGFRs on Ki-67 antigen-positive proliferating cells. Surprisingly, the histological grade of HCC and the expression pattern of VEGFRs showed a characteristic relation; the well-differentiated HCC cases were all distributed in the Flk-1-positive group (7/7), moderately differentiated HCC cases were distributed in either the Flt-1 or Flk-1 single-positive group (20/21), and poorly differentiated HCC cases were predominantly distributed in either the receptor double-negative or double-positive group (6/7). These findings suggest that the expression pattern of VEGFRs influences the histological differentiation of HCC.

Diffusive separation of the lower atmosphere.

The separation of atmospheric constituents by gravity has been proposed theoretically for almost two centuries. However, turbulent mixing has prevented the detection of this phenomenon in the lower atmosphere. By using precise measurements of the Ar/N2 ratio of air samples taken under strong nocturnal inversions, we have detected such separation in near-surface layers. The effect is shown to be consistent with combined influence of thermal and gravimetric separation, with the thermal contribution being more important.

Length of laparotomy incision and surgical stress assessed by serum IL-6 level.

BACKGROUND: Because surgical stress is thought to have an effect on morbidity, mortality, and remnant tumour progression after surgery, diminishing surgical stress is important. The purpose of this study was to assess in a murine model whether the length and type of laparotomy incision influence surgical stress. METHODS: Serum IL-6 concentrations were measured sequentionally in 220 male BALB/c mice who were assigned to different basic laparotomies, (1-cm versus 2-cm versus 3-cm laparotomy with or without caecal resection), other types of laparotomy (3-cm, 1-cm x 3, 3-cm transverse, 3-cm laparotomy with rapid closure), or 3-cm skin incision with or without laparotomy. The serum level of IL-6 was measured by ELISA. RESULTS: Serum IL-6 levels at 3 and 6h after surgery were significantly higher in the 3-cm laparotomy group (1,680+/-802pg/ml and 1,066+/-507pg/ml, respectively), than in the 1-cm laparotomy group (797+/-427pg/ml and 515+/-212pg/ml, respectively). When caecal resection was added, the serum IL-6 level at 6h was significantly higher in the 3-cm laparotomy group (2,844+/-134pg/ml) than in the 1-cm laparotomy group (2,200+/-379pg/ml). Although the type of laparotomy incision was not associated with the serum level of IL-6, the serum IL-6 level after midline skin incision without laparotomy (245+/-142pg/ml) was significantly lower than that after 3-cm laparotomy (1,680+/-802pg/ml). CONCLUSIONS: The length of laparotomy incision was correlated with the serum level of IL-6 in a murine model. The surgical stress related to abdominal procedures might be decreased when laparotomy wounds are kept as small as possible.

Adenocarcinoma in bladder diverticulum, metastatic from gastric cancer.

BACKGROUND: Metastasis to the urinary bladder from gastric cancer is rare. Metastasis to a diverticulum of the bladder from gastric cancer is extremely rare. We report a case of isolated bladder metastasis from gastric cancer and invasion localized to the muscularis propria of the primary site (stomach). CASE PRESENTATION: A 90-year-old female presented with nausea and vomiting that was diagnosed as gastric cancer, the patient also had intermittent hematuria. Pelvic computed tomography identified an abnormally thickened area in the bladder wall that was diagnosed as a diverticulum of the bladder. A biopsy of the bladder wall revealed well differentiated tubular adenocarcinoma metastatic from gastric carcinoma. CONCLUSION: Almost all cases of bladder metastasis from gastric cancer had peritoneal dissemination. This particular presentation of bladder metastasis from gastric cancer, to the best of our knowledge, has not been previously reported.

Identification of an immune tolerance reaction in response to pretreatment with frozen pancreatic tissue in islet cell transplantation in rats.

OBJECTIVES: Whereas transplantation of insulin-secreting pancreatic islets may provide long-term control of glucose metabolism in patients with diabetes mellitus, transplant rejection remains a problem. In this study, we tried pretreatment with frozen pancreatic tissue in a rat model of islet cell transplantation to determine whether induction of immune tolerance is feasible. METHODS: Isolated islet cells from Wistar rats were transplanted into the spleen of recipient rats that were sensitized and rats that were not sensitized with frozen pancreatic tissue. Spleens were analyzed histologically and then examined immunohistochemically for expression of insulin, a pancreas-specific gene. With the use of cDNA primers for proinsulin, RT-PCR was performed to detect islet cells in the spleen. RESULTS: Although islet cells were present in spleens at posttransplantation day (PTD) 1, islet cell clusters in recipients without pretreatment were markedly destroyed on PTD 14 on histologic examination. In contrast, islet cell clusters in recipients sensitized with frozen pancreatic tissue appeared similar to those at PTD 1 even at PTD 14. Proinsulin gene expression was found to be specific to pancreatic tissue. In recipients sensitized with frozen pancreatic tissue, proinsulin gene expression was identified in recipient spleens, even at PTD 14, whereas it was undetected in the absence of pretreatment. In recipients transplanted with islet cells and treated simultaneously with frozen pancreatic tissue, proinsulin gene expression was completely eliminated. The immunohistologic study also showed the presence of insulin-producing islet cells in the spleens of rats sensitized with frozen pancreatic tissue. CONCLUSIONS: Inhibition of the immune reaction in transplant rejection may be mediated by pretreatment with frozen donor tissue.

Gastrointestinal stromal tumor with diffuse mesenteric metastases.

Although malignant gastrointestinal stromal tumors (GISTs) sometimes show peritoneal dissemination, diffuse metastasis to only the mesentery is rare. We describe the unusual case of GIST in a 69-year-old woman who showed multiple nodules restricted only to the mesentery except the surface of the small and large bowel, omentum, and abdominal wall. These small nodules were similar to those seen in leiomyomatosis peritonealis disseminata. Histological and immunohistochemical findings were consistent with GIST. This case of GIST shows an apparently unique and rare spreading pattern.

Less impaired cell-mediated immune response in the murine peritoneal cavity after CO(2) pneumoperitoneum.

PURPOSE: We compared changes in the populations of peritoneal T lymphocytes and natural killer (NK) cells after CO(2) pneumoperitoneum and laparotomy to clarify whether pneumoperitoneum affects cell-mediated immune responses in the peritoneal cavity. METHODS: We analyzed and compared populations of T lymphocytes and NK cells among peritoneal exudative cells (PECs) collected from 185 female mice subjected to pneumoperitoneum, laparotomy, or anesthesia only. PECs were collected postoperatively, and the populations of T lymphocytes and NK cell subsets were analyzed by flow cytometry. The NK cell cytotoxicity (NKCC) of PECs and splenocytes was measured. RESULTS: The populations of CD3(+), CD4(+), and CD8(+) lymphocytes in the PECs continued to increase up until postoperative day (POD) 7 after laparotomy. The CD4/8 ratio on POD 3 was significantly lower after laparotomy than after pneumoperitoneum. The percentages of NK cells in the pneumoperitoneum group were significantly lower than those in the laparotomy group. On POD 1, the NKCC of splenocytes was less impaired in the pneumoperitoneum group than in the laparotomy group (10.3% vs 5.0%, P << 0.05). CONCLUSION: Laparoscopic surgery is preferable to open surgery because it results in less impairment of systemic and intraperitoneal cell-mediated immune responses.

Quality of life after laparoscopic or open colonic resection for cancer.

BACKGROUND/AIMS: Although laparoscopic colectomy has been widely accepted, little is known about the subjective clinical results of this less invasive surgery. The aim of this study was to evaluate the quality of life of patients who had undergone laparoscopic or open colonic resection for cancer. METHODOLOGY: The study included 26 patients with laparoscopic colectomy and 87 with conventional open colectomy for cure of colon cancer. Body temperature, serum C-reactive protein and albumin levels, lymphocyte count, and weight loss during hospital stay were compared between the two groups. Quality of life was estimated by the 9-item questionnaire with scoring system of 1 (high), 2 (fair), and 3 (low). RESULTS: Laparoscopic colectomy was significantly different from open colectomy with regard to the body temperature (37.8 degrees C vs. 38.0 degrees C, p < 0.01) and C-reactive protein level (6.34 mg/dL vs. 11.15 mg/dL, p < 0.01) on postoperative day 1, albumin level (3.54 g/dL vs. 3.36 g/dL, p < 0.05) and lymphocyte count (1354/mm3 vs. 995/mm3, p < 0.01) on postoperative day 7, and weight loss on postoperative day 14 (3.95% vs. 5.45%, p < 0.01). Although all patients with laparoscopic colectomy were satisfied with their surgical results, total score of the quality-of-life questionnaire was not significantly different between the two groups (10.95 vs. 11.81). Both laparoscopic and open colonic resections were similarly accepted by the patients as a good operation that they would recommend to others (1.105 vs. 1.206). CONCLUSIONS: These results indicate that although laparoscopic colonic resection for cancer was less invasive than conventional open colectomy, both laparoscopic and open colonic resections were favorably accepted by the patients, and quality of life after operation was not significantly different between the two procedures.

Surgical technique influences bowel function after low anterior resection and sigmoid colectomy.

BACKGROUND/AIMS: Since June 1996, we have changed surgical strategies to preserve the pelvic autonomic nerve and abandon high ligation of the inferior mesenteric artery. The aim of this study was to clarify the influence of this surgical technique on subjective bowel function of patients with low anterior resection and sigmoid colectomy for cancer. METHODOLOGY: Forty-eight patients who underwent low anterior resection or sigmoid colectomy for cancer during June 1996 and February 2000 replied to the questionnaire which consisted of eight categories of bowel symptoms. Subjective bowel function and operative data of these patients were compared with those obtained from 84 patients with low anterior resection or sigmoid colectomy during April 1984 and May 1996. RESULTS: When recent series were compared with previous series, the frequency of bowel movement at night (21% vs. 60%, p < 0.01) and patient's own judgment as fair or poor (0% vs. 29%, p < 0.01) was decreased in patients with low anterior resection; whereas the frequency of defecation > 2 per day (5% vs. 34%, p < 0.01), difficulty in emptying (32% vs. 71%, p < 0.01), and incomplete evacuation (32% vs. 66%, p < 0.05) was decreased in patients with sigmoid colectomy. Patient judged as poor bowel function was less frequent in the recent group after low anterior resection (25% vs. 71%, p < 0.01) and sigmoid colectomy (18% vs. 42%, p < 0.05) compared with the previous group. Operative data including volume of blood loss, frequency of transfusion, and length of resected specimen were also different between the two groups. CONCLUSIONS: Surgical technique had a significant impact on bowel function following low anterior resection and sigmoid colectomy for cancer. When high ligation of the inferior mesenteric artery is abandoned and the pelvic autonomic nerve is preserved by careful technique, postoperative bowel dysfunction in patients with rectosigmoid colon cancer can be minimized.

AFP-producing gastric carcinoma: multivariate analysis of prognostic factors in 270 patients.

Serum alpha-fetoprotein (AFP) is sometimes high in patients with primary gastric carcinoma, and there is no comprehensive study on the clinicopathologic characteristics and prognostic factors of AFP-producing gastric carcinoma (AGC). To clarify the variables associated with the survival after gastrectomy for AGC, we reviewed the data of patients with AGC and examined the independent prognostic factors. We studied 270 cases of AGC reported in the Japanese literature from June 1982 to March 2001, together with 1 patient of our own experience. The clinicopathologic findings, including serum AFP level, operative curability, and stage of the disease were examined, and factors associated with survival were determined by multivariate analysis. There were 15 stage I tumors (6%), 50 stage II tumors (19%), 51 stage III tumors (20%), and 145 stage IV tumors (55%). The tumors were characterized by frequent serosal invasion (75%), lymph node metastasis (83%), liver metastasis (33%), stage III or IV disease (75%), and noncurative operation (48%). The survival was influenced by the serum AFP level, tumor size, serosal invasion, lymph node metastasis, and liver metastasis, but the independent prognostic factors were operative curability (curative vs. noncurative) and stage of the disease (I, II vs. III, IV). Although the 5-year survival rate and median survival period in all patients were 22% and 14 months, respectively, those in patients with curative gastrectomy were 42% and 29 months, respectively. The results indicate that operative curability and stage of the disease are factors associated with the survival of patients with AGC. Although tumors are often advanced and complicated with liver metastases, long-term survival can be achieved when patients with stage I or II tumor undergo curative gastrectomy.