Stage-Dependent Frequency of Lymph Node Metastases in Patients With Rectal Carcinoma After Preoperative Chemoradiation: Results from the CAO/ARO/AIO-94 Trial and From a Comparative Prospective Evaluation With Extensive Pathological Workup.

BACKGROUND: For patients with ycT1/2 rectal carcinomas after neoadjuvant chemoradiotherapy, local excision instead of radical surgery has increasingly been discussed as a way to avoid postoperative morbidity associated with radical surgery. OBJECTIVE: The purpose of this study was to determine the incidence of lymph node metastases in total mesorectal excision specimens with ypT0, ypT1/2, and ypT3/4 rectal cancers. DESIGN: This is a prospective and retrospective cohort study. SETTINGS: This study was conducted in tertiary referral hospitals that are part of the German Rectal Cancer Study Group. PATIENTS: A total of 479 patients with stage II and III rectal cancers treated within phase III trials of the German Rectal Cancer Study Group were evaluated. Specimens from 81 patients treated in the Working Group of Surgical Oncology/Working Group of Radiation Oncology/Working Group of Medical Oncology of the Germany Cancer Society (CAO/ARO/AIO-04) trial were prospectively studied with extensive microscopic screening of the entire mesorectum. The frequency and localization of nodal metastases were specified and compared with those of 398 patients having received neoadjuvant chemoradiation within the CAO/ARO/AIO-94 trial. MAIN OUTCOME MEASURES: Frequency and localization of mesorectal lymph node metastases in patients with ypT0, ypT1/2, or ypT3/4 cancer were measured. RESULTS: A mean number of 28.0 ± 13.7 nodes were detected per specimen within the prospective group. A total of 25% of patients in the ypT1/2 group had nodal metastases compared with 40% in the ypT3/4 group. Patients with node-positive ypT1/2 had a mean number of 2.2 metastases, and 55% of these metastases were located far from the primary lesion in the proximal mesorectum. Within the CAO/ARO/AIO-94 cohort (n = 398), 19% of patients with ypT1/2 (ypT1 = 22%; ypT2 = 18%) had ypN+ status compared with 43% with ypT3/4 cancers (ypT3 = 40%; ypT4 = 73%). LIMITATIONS: Low numbers of patients with ypT0 limited the evaluation of nodal metastases in pathologic complete responders. CONCLUSIONS: Even in good responders (ypT1/2), >20% of rectal carcinomas still harbored residual lymph node metastases. Local excision for patients with ycT1/2 rectal cancers would, thus, miss metastases in a considerable percentage and might involve the risk of significant undertreatment in a number of patients.

Lymph node metastases in rectal cancer after preoperative radiochemotherapy: impact of intramesorectal distribution and residual micrometastatic involvement.

INTRODUCTION: After neoadjuvant chemoradiation (CRT), the pathologic determined lymph node (LN) status is the most important prognostic factor in rectal cancer patients. Here we assessed the prognostic impact of residual LN micrometastases (<0.2 cm) and the intramesorectal distribution of LN metastases. PATIENTS AND METHODS: Surgical specimens from 81 patients with cUICC II/III rectal cancer undergoing neoadjuvant CRT and total mesorectal excision within the German Rectal Cancer Trial CAO/ARO/AIO-04 were prospectively evaluated. The entire mesorectal compartment was paraffin embedded and screened microscopically. The number and distribution of mesorectal LN macrometastases and micrometastases were correlated with disease-free (DFS) and cancer-specific overall survival (CSS). RESULTS: A total of 2412 LNs were detected (mean 29.8±13.7). Twenty-five patients had residual LN metastases (ypN+). The incidence of metastases in the peritumoral mesorectum was higher (7.7%) than that proximal to the tumor (1.5%), whereas no metastases were identified below the tumor level. Patients with both proximal and peritumoral involvement showed a significantly reduced CSS (hazard ratio=5.4; P<0.05). Fourteen patients with ypN+ status (56%) had micrometastases, 9 patients (36%) had only micrometastatic involvement. Patients with nodal macrometastases had a reduced DFS (P<0.01) and CSS (P<0.005) as compared with ypN0 patients, whereas residual micrometastases had no influence on survival. CONCLUSIONS: Despite the high incidence of residual LN micrometastases they did not seem to have a prognostic impact in this series. Micrometastases might indicate responsive tumors to CRT with a more favorable biology. The intramesorectal distribution of LN metastases had a prognostic impact and should be validated in further studies.

Thymidylate synthase as a prognostic biomarker for locally advanced rectal cancer after multimodal treatment.

PURPOSE: For years, 5-fluorouracil (5-FU) has been the backbone of radiochemotherapy (RCT) of locally advanced rectal cancer. Its main target, thymidylate synthase (TS), is speculated to be an important biomarker for response prediction and long-term prognosis. In this study, we analyzed TS expression in the rectal cancer tissue of 208 patients to evaluate its predictive/prognostic potential. METHODS: All patients included were diagnosed with locally advanced adenocarcinoma of the rectum (UICC II and III) and were treated within randomized clinical trials of the German Rectal Cancer Study Group. Preoperative RCT (50.4 Gy and concomitant either 5-FU or 5-FU and oxaliplatin) was administered in 167 patients followed by surgical resection with total mesorectal excision (TME). Another 41 patients received postoperative RCT. TS levels and further clinicopathological parameters were assessed in univariate and multivariate analyses. Additionally, a TS gene polymorphism was analyzed with respect to the intratumoral protein levels. RESULTS: Low TS expression in pretreatment biopsies correlated with impaired patient survival (p = 0.015). Analysis of a 28-bp repeat revealed a correlation between the *3/*3 genotype and high TS expression in pretherapeutic biopsies. In this study, a correlation of TS expression and grade of RCT-induced tumor regression was not found. Histopathological examination confirmed a complete tumor remission in 16 patients (9.6%). Analyses of the resection specimen indicated an unfavorable prognosis for patients with low intratumoral TS expression in case of detected lymph node metastases (p = 0.04). CONCLUSIONS: TS can serve as a prognostic biomarker indicating an unfavorable prognosis for patients with low TS expression.

Failure of downregulation of survivin following neoadjuvant radiochemotherapy in rectal cancer is associated with distant metastases and shortened survival.

PURPOSE: Valid molecular markers need to be implemented in clinical trials to fulfill the demand of a risk-adapted and more individualized multimodal therapy of locally advanced primary rectal cancer. In this study, the expression of the inhibitor-of-apoptosis (IAP) protein survivin was evaluated in pretreatment biopsies and corresponding posttreatment resection specimens, and was correlated to histo-pathological tumor characteristics and clinical follow-up. PATIENTS AND METHODS: One hundred sixteen patients with stage II/III rectal cancer treated with 5-FU-based neoadjuvant radiochemotherapy (RCT) at a single university medical centre within the German Rectal Cancer Trials were investigated. Survivin expression in pretreatment biopsies and surgical resection specimens were determined by immunohistochemistry by two independent institutions and correlated with histopathologic parameters, tumor recurrences, disease-free (DFS), and overall cancer-specific survival (CSS). RESULTS: In pretreatment biopsies, a higher survivin expression correlated with advanced ypT (P = 0.026) and ypUICC (P = 0.05) stage as well as DFS (P = 0.038) after preoperative RCT. High posttreatment survivin levels were associated with advanced ypT stage (P = 0.03) and residual lymph node metastases (P = 0.04). Moreover, neoadjuvant RCT resulted in a significant downregulation of survivin expression (P < 0.0001). A failure of RCT-induced downregulation was associated with development of distant metastases (P = 0.0056) and cancer-related death (P = 0.026), and correlated significantly with DFS (P = 0.011*/0.02**) and CSS (P = 0.0017*/0.01**) in uni-* and multivariate** analyses. CONCLUSIONS: Survivin expression displays a marker with prognostic utility in rectal cancers. These results underline the potential of survivin to monitor individual response to RCT and encourage anti-survivin strategies in multimodal rectal cancer therapy within future randomized clinical trials.

Stage II/III rectal cancer with intermediate response to preoperative radiochemotherapy: do we have indications for individual risk stratification?

BACKGROUND: Response to preoperative radiochemotherapy (RCT) in patients with locally advanced rectal cancer is very heterogeneous. Pathologic complete response (pCR) is accompanied by a favorable outcome. However, most patients show incomplete response. The aim of this investigation was to find indications for risk stratification in the group of intermediate responders to RCT. METHODS: From a prospective database of 496 patients with rectal adenocarcinoma, 107 patients with stage II/III cancers and intermediate response to preoperative 5-FU based RCT (ypT2/3 and TRG 2/3), treated within the German Rectal Cancer Trials were studied. Surgical treatment comprised curative (R0) total mesorectal excision (TME) in all cases. In 95 patients available for statistical analyses, residual transmural infiltration of the mesorectal compartment, nodal involvement and histolologic tumor grading were investigated for their prognostic impact on disease-free (DFS) and overall survival (OS). RESULTS: Residual tumor transgression into the mesorectal compartment (ypT3) did not influence DFS and OS rates (p = 0.619, p = 0.602, respectively). Nodal involvement after preoperative RCT (ypN1/2) turned out to be a valid prognostic factor with decreased DFS and OS (p = 0.0463, p = 0.0236, respectively). Persistent tumor infiltration of the mesorectum (ypT3) and histologic tumor grading of residual tumor cell clusters were strongly correlated with lymph node metastases after neoadjuvant treatment (p < 0.001). CONCLUSIONS: Advanced transmural tumor invasion after RCT does not affect prognosis when curative (R0) resection is achievable. Residual nodal status is the most important predictor of individual outcome in intermediate responders to preoperative RCT. Furthermore, ypT stage and tumor grading turn out to be additional auxiliary factors. Future clinical trials for risk-adapted adjuvant therapy should be based on a synopsis of clinicopathologic parameters.

High-grade acute organ toxicity during preoperative radiochemotherapy as positive predictor for complete histopathologic tumor regression in multimodal treatment of locally advanced rectal cancer.

PURPOSE: To test for a possible correlation between high-grade acute organ toxicity during preoperative radiochemotherapy and complete tumor regression after total mesorectal excision in multimodal treatment of locally advanced rectal cancer. PATIENTS AND METHODS: From 2001 to 2008, 120 patients were treated. Preoperative treatment consisted of normofractionated radiotherapy at a total dose of 50.4 Gy, and either two cycles of 5-fluorouracil (5-FU) or two cycles of 5-FU and oxaliplatin. Toxicity during treatment was monitored weekly, and any toxicity CTC (Common Toxicity Criteria) >or= grade 2 of enteritis, proctitis or cystitis was assessed as high-grade organ toxicity for later analysis. Complete histopathologic tumor regression (TRG4) was defined as the absence of any viable tumor cells. RESULTS: A significant coherency between high-grade acute organ toxicity and complete histopathologic tumor regression was found, which was independent of other factors like the preoperative chemotherapy schedule. The probability of patients with acute organ toxicity >or= grade 2 to achieve TRG4 after neoadjuvant treatment was more than three times higher than for patients without toxicity (odds ratio: 3.29, 95% confidence interval: [1.01, 10.96]). CONCLUSION: Acute organ toxicity during preoperative radiochemotherapy in rectal cancer could be an early predictor of treatment response in terms of complete tumor regression. Its possible impact on local control and survival is under further prospective evaluation by the authors' working group.

Preoperative chemoradiotherapy does not necessarily reduce lymph node retrieval in rectal cancer specimens--results from a prospective evaluation with extensive pathological work-up.

PURPOSE: Preoperative chemoradiotherapy (CRT) is supposed not only to reduce lymph node metastases but also lymph node recovery in rectal cancer specimens. The objective of this prospective study was to determine the effects of chemoradiation on mesorectal lymph node retrieval under terms of a meticulous histopathological evaluation. METHODS: Specimens from 64 consecutive patients with stage II/III rectal cancer receiving preoperative 5-FU-based CRT were investigated. All patients were treated within the German Rectal Cancer Trial CAO/ARO/AIO-04. After surgery (including quality assessed total mesorectal excision), extensive pathological diagnostics was performed with embedding and microscopic evaluation of the whole mesorectal soft tissue compartment. RESULTS: A total number of 2,021 lymph nodes were recovered (31.6 per specimen) within pathological work-up. There was no significant correlation between the number of retrieved nodes and patient- as well as tumor-dependent parameters. Lymph node size constantly amounted for less than 0.5 cm. Twenty patients (31.3%) had persistent nodal metastases. A considerable incidence of residual micrometastatic involvement in lymph nodes <0.3 cm (in 9.4% of all patients) was detected by extensive pathologic work-up. CONCLUSION: Reliable nodal staging with high numbers of detected nodes was feasible after neoadjuvant CRT. Micrometastases frequently occur in small lymph nodes detected by microscopic evaluation.

Gold markers for tumor localization and target volume delineation in radiotherapy for rectal cancer.

BACKGROUND AND PURPOSE: In locally advanced rectal cancer, neoadjuvant radiochemotherapy is indicated. To improve target volume definition for radiotherapy planning, the potential of implanted gold markers in the tumor region was evaluated. PATIENTS AND METHODS: In nine consecutive patients, two to three gold markers were implanted in the tumor region during rigid rectoscopy. Computed tomography scans were performed during treatment planning. All electronic portal imaging devices (EPIDs) recorded during treatment series were analyzed. All patients underwent complete tumor resection with meticulous histopathologic examination. RESULTS: The gold markers could easily be implanted into the mesorectal tissue at the caudal tumor border without any complications. They were helpful in identifying the inferior border of the planning target volume in order to spare normal tissue (in particular anal structures). No significant shift of the markers was found during the course of therapy. Marker matching of the EPIDs did not improve patient positioning in comparison to bone structure matching. The former position of at least one marker could be identified in all patients during histopathologic examination. CONCLUSION: The use of gold marker enables a more precise definition of the target volume for radiotherapy in patients with rectal cancer. This could eventually allow a better protection of anal structures of patients with a tumor localization > or = 5 cm cranial of the anal sphincter. The implantation of the gold markers improved communication between the surgeon, the radiooncologist and the pathologist resulting in intensified exchange of relevant informations.

Irradiation as preparative regimen for hepatocyte transplantation causes prolonged cell cycle block.

PURPOSE: Hepatocyte transplantation following liver irradiation (IR) and partial hepatectomy (PH) leads to extensive liver repopulation. We investigated the changes in the liver induced by IR explaining the loss of reproductive integrity in endogenous hepatocytes. MATERIALS AND METHODS: Right lobules of rat liver underwent external beam IR (25 Gy). A second group was subjected to additional 33% PH of the untreated left liver lobule. Liver specimens and controls were analyzed for DNA damage, apoptosis, proliferation and cell cycle related genes (1 hour to up to 12 weeks). RESULTS: Double strand breaks (phosphorylated histone H2AX) induced by IR rapidly declined within hours and were no longer detectable after 4 days. No significant apoptosis was noted and steady mRNA levels (B-cell lymphoma 2-associated X protein (BAX), caspase 3 and 9) were in line with the lack of DNA fragmentation. However, gene expression of p53 and p21 in irradiated liver tissue increased. Transcripts of cyclin D1, proliferating cell nuclear antigen (PCNA), and cyclin B augmented progressively, whereas cyclin E was only affected moderately. Following PH, irradiated livers displayed persistently high protein levels of p21 and cyclin D1. However, cell divisions were infrequent, as reflected by low PCNA levels up to four weeks. CONCLUSION: IR leads to a major arrest in the G(1)/S phase and to a lesser extent in the G(2)/M transition of the cell cycle, resulting in reduced regenerative response following PH. The persistent block of at least four weeks may promote preferential proliferation of transplanted hepatocytes in this milieu.