Background: The optimal treatment for locally recurrent rectal cancer (LRRC) is still a matter of debate. This study assessed the outcome of LRRC patients treated with multimodality treatment, consisting of neoadjuvant radio (chemo-) therapy, extended resection, and intraoperative radiotherapy.Methods: One hundred and forty-seven consecutive patients with LRRC who underwent treatment between 1994 and 2006 were studied. The prognostic values of patient-, tumor-and treatment-related characteristics were tested with uni-and multivariate analysis.Results: Median overall survival was 28 months (range 0-146 months). Five-year overall, disease-free, and metastasis-free survival and local control (OS, DFS, MFS, and LC respectively) were 31.5%, 34.1%, 49.5% and 54.1% respectively. Radical resection (R0) was obtained in 84 patients (57.2%), microscopically irradical resection (R1) in 34 patients (23.1%), and macroscopically irradical resection (R2) in 29 patients (19.7%). For patients with a radical resection median OS was 59 months and the 5-year OS, DFS, MFS, and LC were 48.4%, 52.3%, 65.5% and 68.9%, respectively. Radical resection was significantly correlated with improved OS, DFS, and LC (P \ 0.001). Patients who received re-irradiation or full-course radiotherapy survived significantly longer (P = 0.043) and longer without local recurrence (P = 0.038) or metastasis (P \ 0.001) compared to patients who were not re-irradiated.Conclusions: Radical resection is the most significant predictor of improved survival in patients with LRRC. Neoadjuvant radio (chemo-) therapy is the best option in order to realize a radical resection. Re-irradiation is feasible in patients who already received irradiation as part of the primary rectal cancer treatment.

Tumor budding is a histological feature that reflects loss of adhesion of tumor cells and is associated with locoregional metastasis of colorectal carcinoma. Although nuclear localization of b-catenin is associated with tumor budding, the molecular mechanism remains largely elusive. In this study, we hypothesize that the epithelial cell adhesion molecule (Ep-CAM) is involved in tumor budding. In order to address this question, we performed immunohistochemistry on Ep-CAM using three different antibodies (monoclonal antibodies Ber-ep4 and 311-1K1 and a polyclonal antibody) and a double staining on b-catenin and Ep-CAM. In addition, Ep-CAM mRNA was monitored with mRNA in situ hybridization. Subsequently, we determined the effect of Ep-CAM staining patterns on tumor spread in rectal cancer. In contrast to the tumor mass, budding cells of colorectal carcinoma displayed lack of membranous but highly increased cytoplasmic Ep-CAM staining and nuclear translocation of b-catenin. mRNA in situ hybridization suggested no differences in Ep-CAM expression between the invasive front and the tumor mass. Importantly, reduced Ep-CAM staining at the invasive margin of rectal tumor specimens (n ¼ 133) correlated significantly with tumor budding, tumor grade and an increased risk of local recurrence (P ¼ 0.001, P ¼ 0.04 and P ¼ 0.03, respectively). These data demonstrate abnormal processing of Ep-CAM at the invasive margin of colorectal carcinomas. Our observations indicate that loss of membranous Ep-CAM is associated with nuclear b-catenin localization and suggest that this contributes to reduced cell-cell adhesions, increased migratory potential and tumor budding.

Purpose: After preoperative (radio)chemotherapy, histologic determinants for prognostification have changed. It is unclear which variables, including assessment of tumor regression, are the best indicators for local recurrence and survival. Experimental Design: A series of 201 patients with locally advanced rectal cancer (cT3/T4, M0) presenting with an involved or at least threatened circumferential margin (CRM) on preoperative imaging (<2 mm) were evaluated using standard histopathologic variables and four different histologic regression systems. All patients received neoadjuvant radiochemotherapy or radiotherapy. The prognostic value of all factors was tested with univariate survival analysis of time to local recurrence and overall survival. Results: Local recurrence occurred in only 8% of the patients with a free CRM compared with 43% in case of CRM involvement (P < 0.0001). None of the four regression systems were associated with prognosis, not even when corrected for CRM status. However, we did observe a higher degree of tumor regression after radiochemotherapy compared with radiotherapy (P < 0.001). Absence of tumor regression was associated with increasing invasion depth and a positive CRM (P = 0.02 and 0.03, respectively). Conclusions: Assessment of CRM involvement is the most important pathologic variable after radiochemotherapy. Although tumor regression increases the chance on a free CRM, in cases with positive resection margins prognosis is poor irrespective of the degree of therapyinduced regression.

Approximately 10% of all colorectal carcinomas are mucinous carcinomas, characterized by extracellular mucin. Occasionally, mucin accumulates intracellularly in these tumours, causing signet ring cell differentiation. We hypothesized that signet ring cells arise from a separate genetic pathway. In this study the molecular background of signet ring cell differentiation was investigated by analysing genetic changes, changes in the expression of adhesion molecules, and mucin content. Furthermore, its clinical relevance was addressed. Cell lines of colorectal tumours with non-mucinous (AC), mucinous (MC), and signet ring cell phenotype (MCSRC) were used for Multiplex Ligation-dependent Probe Amplification to detect deletions and amplifications in specific oncogenes and tumour suppressor genes. Furthermore, the expression of E-cadherin, beta-catenin, ITF (intestinal trefoil factor), and MUC2 in signet ring cells was studied by immunohistochemistry, immunofluorescence, and mRNA in situ hybridization. Results were validated using a large cohort of rectal carcinomas from which clinicopathological data were available. Specific amplifications and deletions in cell lines of AC, MC, and MCSRC were detected. Bcl-2 was amplified in MCSRC and MC cell lines, but not in AC cell lines. Bcl-2 FISH analysis confirmed this in patient material. Signet ring cells had decreased expression of adhesion molecules (E-cadherin, beta-catenin) and were strongly positive for ITF and MUC2, two peptides which are normally only produced by goblet cells. RNA in situ hybridization confirmed the production of ITF. Mucinous carcinomas with signet ring cell differentiation presented at a higher T stage than adenocarcinomas and mucinous carcinomas (16% pT4 versus 3-5%, p<0.001) and were more frequently node positive (77% vs 39-44%; p<0.001). Prognosis was significantly worse. In conclusion, the presence of signet ring cells in carcinomas with mucinous differentiation correlates with increased T-stage and poor prognosis. These cells, characterized by ITF and MUC2 production, show disruption of the E-cadherin/beta-catenin complex, as well as amplification of Bcl-2.

Purpose: The combination of radiotherapy and good quality surgery reduces local recurrence rate for rectal cancer patients. This study assesses the prognostic value of both intrinsic and radiotherapy-induced apoptosis and evaluates the relevance of radiotherapy for outcome of rectal cancer patients. Experimental Design: Tumor samples (1,198) were available from the Dutch Total Mesorectal Excision trial, in which rectal cancer patients were treated with standardized surgery and randomized for preoperative short-term radiotherapy or not. Tumor samples were obtained at time of surgery. Tissue microarrays were constructed and stained with the active caspase-specific M30 antibody to determine the amount of apoptotic epithelial tumor cells. Results: Nonirradiated patients with a negative circumferential margin displaying lower than median levels of apoptosis developed more local recurrences (10.5% versus 6.1%; P = 0.06) and more rapidly after surgery than patients with high intrinsic apoptosis in their tumors (median time to recurrence, 13.0 versus 21.3 months; P = 0.04). In multivariate analysis, intrinsic apoptosis was an independent predictor for the development of local recurrences (hazard ratio, 2.0; P = 0.05). Radiotherapy increased apoptosis level (11 versus 23 apoptotic cells/mm 2 tumor epithelium; P < 0.001), but this apoptosis did not influence patients' prognosis.Conclusions: Rectal cancer patients with low intrinsic apoptosis will benefit from radiotherapy with respect to the development of local recurrences. Because apoptosis is an inherent characteristic of tumors, patients who do not need radiotherapy may be selected based on the apoptotic index of the primary tumor.Local recurrences are a serious problem in the treatment of rectal cancer. To improve local control, total mesorectal excision (TME) surgery has been introduced (1). In addition to TME, preoperative radiotherapy resulted in a further reduction of local recurrences (2) and has been accepted recently as standard treatment for rectal cancer patients in the Netherlands.Although radiotherapy can prevent local recurrences in some patients, the majority of patients will not develop a recurrence without radiotherapy. Moreover, radiotherapy has several negative side effects (3, 4), emphasizing the need for prognostic indicators to select patients most likely benefiting from radiotherapy. Because radiotherapy is known to induce DNA damage, which can result in apoptotic cell death, the better local control observed after radiotherapy might result from the induction of apoptosis. During tumor development, tumor cells can be triggered by lymphocytes of the patient's immune system or other stress factors, such as growth factor deprivation, to undergo apoptosis (5, 6). However, tumor cells that acquired multiple antiapoptotic mutations fail to undergo apoptosis, resulting in selective outgrowth of these cells. The level of apoptosis, both intrinsic and after radiotherapy, might therefore have a prognostic value for the clinical outcome of rectal ...