Target volume delineation variation in radiotherapy for early stage rectal cancer in the Netherlands.

PURPOSE: The aim of this study was to measure and improve the quality of target volume delineation by means of national consensus on target volume definition in early-stage rectal cancer. METHODS AND MATERIALS: The CTV's for eight patients were delineated by 11 radiation oncologists in 10 institutes according to local guidelines (phase 1). After observer variation analysis a workshop was organized to establish delineation guidelines and a digital atlas, with which the same observers re-delineated the dataset (phase 2). Variation in volume, most caudal and cranial slice and local surface distance variation were analyzed. RESULTS: The average delineated CTV volume decreased from 620 to 460 cc (p<0.001) in phase 2. Variation in the caudal CTV border was reduced significantly from 1.8 to 1.2 cm SD (p=0.01), while it remained 0.7 cm SD for the cranial border. The local surface distance variation (cm SD) reduced from 1.02 to 0.74 for anterior, 0.63 to 0.54 for lateral, 0.33 to 0.25 for posterior and 1.22 to 0.46 for the sphincter region, respectively. CONCLUSIONS: The large variation in target volume delineation could significantly be reduced by use of consensus guidelines and a digital delineation atlas. Despite the significant reduction there is still a need for further improvement.

Concomitant hyperthermia and radiation therapy for treating locally advanced rectal cancer.

BACKGROUND: Surgery has been the treatment of choice for patients with rectal cancer. For locally advanced cancer results were poor, with high rates of locoregional recurrences and poor overall survival data. Adding (chemo)radiotherapy upfront improved results mainly in locoregional control. Adding hyperthermia to radiotherapy preoperatively might have an equivalent beneficial effect. OBJECTIVES: To quantify the potential beneficial effect of thermo radiation compared to chemo-radiation with respect to pathological complete responses, overall survival and toxicity in rectal cancer therapy. SEARCH STRATEGY: We identified the relevant phase II and III randomised controlled trials in any language trough electronic searches May 2007 of the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2007), the Cochrane Colorectal Cancer Groups Specialised Register, MEDLINE (from 1966), EMBASE (from 1974), CINAHL (from 1982). Furthermore, various trial databases were searched for the identification of recent completed and ongoing trials (metaRegister of Controlled Trials, Cancer Research UK, Cancer.gov, The Eastern Cooperative Oncology Group Trials Database). All studies identified until May 2007 were considered for inclusion in the present study. SELECTION CRITERIA: Only phase II and III randomised controlled clinical trials were included in the analysis. DATA COLLECTION AND ANALYSIS: All identified studies were assessed by two independent reviewers. A weighted estimate of the treatment effect was computed for 2, 3, 4 and 5-year survival, for local tumour recurrence, severe acute and late toxicity and complete tumour response (CR). CR was defined either clinically by disappearance of all pretreatment signs of local tumour or pathologically by microscopically free margins. The risk ratio (RR) and hazard ratio (HR) were used. Analyses were performed with the Reference Manager (RevMan). MAIN RESULTS: Six RCTs published between 1990 and 2007 were identified. A total number of 520 patients was treated, 258 in the radiotherapy only arm (RT) and 262 in the radiotherapy-hyperthermia arm (RHT). Four studies (424 patients) reported overall survival (OS) rates. After 2 years, OS was significantly better in the RHT group (HR 2.06; 95% CI 1.33-3.17; p=.001), but this difference disappeared after a longer period (3, 4 and 5 year OS). All but one studies reported CR rates. A significant higher CR rate was observed in the RHT group (RR 2.81; 95% CI 1.22-6.45; p=.01). Only 2 studies reported on acute toxicity. In these 2 studies no significant differences were observed between the RT and the RHT group. Late toxicity data were not reported. AUTHORS' CONCLUSIONS: Further studies are needed to compare chemoradiation versus thermoradiation versus chemoradiation plus hyperthermia in well selected/conducted and quality controlled randomised trials.

Multislice CT as a primary screening tool for the prediction of an involved mesorectal fascia and distant metastases in primary rectal cancer: a multicenter study.

PURPOSE: The purposes of this study were to assess whether multislice CT can identify tumors having a free or involved circumferential margin, to investigate the additional role of multislice CT as a "one-stop shopping" staging tool for staging nodal and distant metastases. METHODS: A total of 250 patients with adenocarcinoma of the rectum underwent multislice CT scans of the chest and abdomen before undergoing total mesorectal excision. The scans were scored by two teams. The main outcome was yes/no involvement of the mesorectal fascia. Histology was taken as the standard for determining the involvement. RESULTS: The overall sensitivity for predicting an involved mesorectal fascia was 74.2 percent and the overall specificity was 93.9 percent. The overall sensitivity for low tumors was 65.6 percent and the overall specificity was 81.5 percent. The overall sensitivity for mid-/high rectal tumors was 76.1 percent and the overall specificity was 96.3 percent. The interobserver agreement was substantial (kappa 0.695). The overall sensitivity for the prediction of liver metastases was 64.3 percent and the overall specificity was 94.4 percent with kappa 0.82. The accuracy in predicting lymph node metastases was low. CONCLUSIONS: Multislice CT can be used for the assessment of mesorectal fascia involvement in primary rectal cancer, especially those located in the middle rectum and the high rectum; however, in the prediction of an involved margin of tumors located in the distal rectum, the accuracy of multislice CT falls short.

Conventional CT for the prediction of an involved circumferential resection margin in primary rectal cancer.

PURPOSE: To determine the accuracy of conventional computed tomography (CT) scan in the preoperative prediction of an involved circumferential resection margin (CRM) in primary rectal cancer. METHODS: 125 patients with biopsy-proven adenocarcinoma of the rectum underwent CT of the abdomen before undergoing total mesorectal excision. Scans were scored by three observers, differing in experience. The main outcome was yes/no involvement of the CRM. Histology was taken as reference standard. RESULTS: For the most experienced observer, observer A, sensitivity was 46.7% and specificity 92.6%. For observer B, sensitivity was 46.7% and specificity 89.5%. For the least experienced observer C, sensitivity was 43.3% and specificity 92.6%. Inter-observer variability was good between observers A and B (kappa 0.648), B and C (kappa 0.648), and intermediate between A and C (kappa 0.542). Discrepancies occurred in a total of 34 patients; 25 had a CT scan of low technical quality, 10 an anteriorly located distal tumor. CONCLUSION: Conventional CT scan lacks sensitivity for a clinical use in the preoperative assessment of an involved CRM in primary rectal cancer. Modern multislice spiral CT will probably resolve some of the problems of conventional CT; however, further research is needed to establish its role.