Lena-Christin Conradi

Irradiation with protons for the individualized treatment of patients with locally advanced rectal cancer: A planning study with clinical implications

BACKGROUND AND PURPOSE Ongoing clinical trials aim to improve local control and overall survival rates by intensification of therapy regimen for patients with locally advanced rectal cancer. It is well known that whenever treatment is intensified, risk of therapy-related toxicity rises. An irradiation with protons could possibly present an approach to solve this dilemma by lowering the exposure to the organs-at-risk (OAR) without compromising tumor response. MATERIAL AND METHODS Twenty five consecutive patients were treated from 04/2009 to 5/2010. For all patients, four different treatment plans including protons, RapidArc, IMRT and 3D-conformal-technique were retrospectively calculated and analyzed according to dosimetric aspects. RESULTS Detailed DVH-analyses revealed that protons clearly reduced the dose to the OAR and entire normal tissue when compared to other techniques. Furthermore, the conformity index was significantly better and target volumes were covered consistent with the ICRU guidelines. CONCLUSIONS Planning results suggest that treatment with protons can improve the therapeutic tolerance for the irradiation of rectal cancer, particularly for patients scheduled for an irradiation with an intensified chemotherapy regimen and identified to be at high risk for acute therapy-related toxicity. However, clinical experiences and long-term observation are needed to assess tumor response and related toxicity rates.

CpG island methylator phenotype infers a poor disease-free survival in locally advanced rectal cancer

BACKGROUND Locally advanced rectal cancers are treated with preoperative radiochemotherapy (RCT). However, subsets of patients have no benefit from preoperative treatment. Since epigenetic modifications, including DNA methylation, may influence response to neoadjuvant treatment we studied the CpG island methylator phenotype (CIMP) in patients who received a 5-fluouracil based RCT. METHODS One hundred fifty patients with locally advanced rectal cancer, treated within a phase III clinical trial (CAO/ARO/AIO-94 and -04), were included in this analysis. CIMP was assessed by methylation specific PCR (MSP) using RUNX3, SOCS1, NEUROG1, IGF2, and CACNA1G as a marker panel. Loss of mismatch repair gene (MMR) expression was assessed by immunohistochemistry for a subset of patients. KRAS and BRAF mutation status were assessed using Sanger sequencing. RESULTS The CIMP status could be established in all 150 patients. Fifteen (10%) revealed CIMP positivity (≥3 methylated promoters), whereas 135 patients (90%) where classified as CIMP negative. Analysis for MMR status did not reveal any microsatellite instability (MSI). A single mutation of the BRAF gene (D594G) was detected. The KRAS gene (exon 1, 2, and 3) was mutated in 65 tumors (43%) but was not correlated to a specific CIMP status. Three- and 5-year disease-free survival was notably worse in CIMP positive patients (56% and 0% vs 80% and 75%; P < .01) suggesting an increased likelihood of poor clinical outcome (HR 5.5; 95%CI: [2.1, 13.9]). CONCLUSION CIMP positivity, defined by methylation of at least 3 specific gene promoters, is an infrequent event in locally advanced rectal cancer. However, it increases the likelihood of distant metastases. Therefore, the CIMP status may be included as a molecular marker for the identification of high-risk patients and might contribute to individual treatment stratification.

Optimal lymph node harvest in rectal cancer (UICC stages II and III) after preoperative 5-FU-based radiochemotherapy. Acetone compression is a new and highly efficient method.

Introduction:Preoperative 5-fluorouracil–based radiochemotherapy (RCT), followed by total mesorectal excision, is accepted as standard therapy in rectal cancers (UICC stages II and III). The accurate evaluation of ypN status after RCT with valuable lymph node (LN) harvest is essential for postoperative risk-adapted treatment decisions. Actual numbers of assessed LNs and validity of ypN status vary extensively depending on the methods used. Material and Methods:This prospective study validates the acetone compression (AC), whole mesorectal compartment embedding (WME), and fat clearance (FC) methods for LN retrieval in n=257 rectal cancer specimens obtained from 2 high-volume surgical centers. For optimal LN retrieval, the AC method (n=161 specimens: 52 cases with RCT, 109 cases without RCT) was compared with the WME (n=64 cases, with RCT) and FC methods (n=32 cases: 17 cases with RCT, 15 cases without RCT). The efficacy of LN retrieval, costs involved, and molecular diagnostics were measured. Results:Using the AC method, 41 LNs (mean; range 14 to 86 LNs) were detectable in total mesorectal excision specimens after RCT and 44 LNs (mean; range 9 to 78 LNs) in cases without RCT. The LN yield after RCT obtained by using the AC method was equivalent to that of the WME method (mean 32 LNs/specimen; range 12 to 81 LNs) but demonstrated a better time and cost-efficacy. In addition, the AC method facilitated assessment of any tumor deposits, including perineural invasion, and did not hamper molecular analyses. The AC method increased LN retrieval 4- to-6-fold as compared with the literature and 2-fold compared with manual dissection after the FC method. Discussion:The AC method is the method of choice for accurate LN staging in locally advanced rectal cancer, especially after preoperative RCT, and is well suited for routine gastrointestinal pathology workup.

Frequency of HER-2 positivity in rectal cancer and prognosis.

In patients with advanced rectal cancer (cUICC II and III) multimodality therapy resulted in better long-term local tumor control. Ongoing clinical trials are focusing on therapy intensification to improve disease-free (DFS) and cancer-specific survival (CSS), the integration of biomarkers for prediction of individual recurrence risk, and the identification of new targets. In this context, we investigated HER-2, a member of the epidermal growth factor receptor family, whose expression pattern and role was unclear in rectal cancer. A total of 264 patients (192 male, 72 female; median age 64 y) received standardized multidisciplinary treatment according to protocols of phase II/III trials of the German Rectal Cancer Study Group. HER-2 status was determined in pretherapeutic biopsies and resection specimens using immunohistochemistry scoring and detection of silver in situ hybridization amplification. Tumors with an immunohistochemistry score of 3+ or silver in situ hybridization ratios of ≥2.0 were classified HER-2 positive; these results were correlated with clinicopathologic parameters [eg, resection (R) status, nodal status ((y)pN)], DFS, and CSS. Positive HER-2 status was found in 12.4% of biopsies and in 26.7% of resected specimens. With a median follow-up of 46.5 months, patients with HER-2 positivity showed in trend a better DFS (P=0.1) and a benefit in CSS (P=0.03). The 5-year survival rate was 96.0% (HER-2 positive) versus 80.0% (HER-2 negative). In univariate and multivariate analyses, HER-2 was an independent predictor for CSS (0.02) along with the (y)pN status (P<0.00001) and R status (P=0.011). HER-2 amplification is detectable in a relevant proportion (26.7%) of rectal cancer patients. For the development of innovative new therapies, HER-2 may represent a promising target and should be further assessed within prospective clinical trials.

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. Clin Cancer Res; 17(6); 1623–31. ©2010 AACR.

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.

Enrichment of CD133-expressing cells in rectal cancers treated with preoperative radiochemotherapy is an independent marker for metastasis and survival

The transmembrane glycoprotein CD133 (cluster of differentiation 133; also known as Prominin or PROM1) has been described as a potential stem cell marker in colorectal cancer and is associated with higher tumorigenic potential and resistance to radiochemotherapy (RCT). In this study, CD133 expression was evaluated in pre‐RCT tumor biopsies and the corresponding post‐RCT surgical specimens from patients with locally advanced rectal adenocarcinoma, and expression levels were correlated with histopathologic features and clinical follow‐up.

Gender-Specific Acute Organ Toxicity during Intensified Preoperative Radiochemotherapy for Rectal Cancer

Patients with locally advanced rectal cancer (cUICC stages II/III) are typically treated with preoperative 5-fluorouracil-based (5-FU-based) radiochemotherapy (RCT). However, trials are currently being conducted to improve the complete remission rates and the systemic control by combining 5-FU with oxaliplatin. The primary objective was to identify the subgroups of rectal cancer patients who were at risk for high-grade toxicity. All 196 patients who were included in the present study were treated with 50.4 Gy and chemotherapy that included either 5-FU (n = 115) or 5-FU+oxaliplatin (n = 81). The preoperative RCT was followed by a total mesorectal excision and adjuvant chemotherapy. Acute toxicity was monitored weekly and a toxicity grade ≥3 (Common Toxicity Criteria) for a skin reaction, cystitis, proctitis, or enteritis was defined as high-grade acute organ toxicity. After RCT with 5-FU+oxaliplatin, complete tumor remission was achieved in 13.6% of the patients and in 11.3% after RCT with 5-FU alone. Complete irradiation dosages of 50.4 Gy were given to 99% (5-FU) and 95% (5-FU+oxaliplatin) of the patients. Concomitant chemotherapy was fully administered in 95% of the patients treated with 5-FU compared with the 84% of patients treated with 5-FU+oxaliplatin. A significantly higher proportion of acute organ toxicity was found in the patients who were treated with 5-FU+oxaliplatin compared with those who were treated with 5-FU. Additionally, women with a low body mass index were at the highest risk for acute organ toxicity. These results suggest that there are basic clinical parameters, such as gender and body mass index, that may be potential markers for generating individual risk profiles of RCT-induced toxicity.

Gender affects acute organ toxicity during radiochemotherapy for rectal cancer: Long-term results of the German CAO/ARO/AIO-94 phase III trial

INTRODUCTION The CAO/ARO/AIO-94 phase-III-trial demonstrated a significant improvement of preoperative chemoradiotherapy (CRT) versus postoperative CRT on local control for UICC stage II/III rectal cancer patients, but no effect on long-term survival. In this add-on evaluation, we investigated the association of gender and age with acute toxicity and outcome. PATIENTS AND METHODS According to actual treatment analyses, 654 of 799 patients had received pre- (n=406) or postoperative CRT (n=248); in 145 patients postoperative CRT was not applied. Gender, age and clinicopathological parameters were correlated with CRT-associated acute toxicity and survival. RESULTS The 10-year survival was higher in women than in men, with 72.4% versus 65.6% for time to recurrence (p=0.088) and 62.7% versus 58.4% for overall-survival (OS) (p=0.066), as expected. For patients receiving CRT, women showed higher hematologic (p<0.001) and acute organ toxicity (p<0.001) in the entire cohort as well as in subgroup analyses according to pre- (p=0.016) and postoperative CRT (p<0.001). Lowest OS was seen in patients without acute toxicity (p=0.0271). Multivariate analyses for OS showed that acute organ toxicity (p=0.034) was beneficial while age (p<0.001) was associated with worse OS. DISCUSSION Female gender is significantly associated with CRT-induced acute toxicity in rectal cancer. Acute toxicity during CRT may be associated with improved long-term outcome.

Acute Toxicity of Radiochemotherapy in Rectal Cancer Patients: A Risk Particularly for Carriers of the TGFB1 Pro25 variant

PURPOSE Transforming growth factor-beta1 is related to adverse events in radiochemotherapy. We investigated TGFB1 genetic variability in relation to quality of life-impairing acute organ toxicity (QAOT) of neoadjuvant radiochemotherapy under clinical trial conditions. METHODS AND MATERIALS Two independent patient cohorts (n = 88 and n = 75) diagnosed with International Union Against Cancer stage II/III rectal cancer received neoadjuvant radiation doses of 50.4 Gy combined with 5-fluorouracil-based chemotherapy. Toxicity was monitored according to Common Terminology Criteria for Adverse Events. QAOT was defined as a CTCAE grade ≥2 for at least one case of enteritis, proctitis, cystitis, or dermatitis. Nine germline polymorphisms covering the common genetic diversity in the TGFB1 gene were genotyped. RESULTS In both cohorts, all patients carrying the TGFB1 Pro25 variant experienced QAOT (positive predictive value of 100%, adjusted p = 0.0006). In a multivariate logistic regression model, gender, age, body mass index, type of chemotherapy, or disease state had no significant impact on QAOT. CONCLUSION The TGFB1 Pro25 variant could be a relevant marker for individual treatment stratification and carriers may benefit from adaptive clinical care or specific radiation techniques.