Neoadjuvant chemoradiotherapy with or without panitumumab in patients with wild-type KRAS, locally advanced rectal cancer (LARC): a randomized, multicenter, phase II trial SAKK 41/07.

BACKGROUND: We conducted a randomized, phase II, multicenter study to evaluate the anti-epidermal growth factor receptor (EGFR) mAb panitumumab (P) in combination with chemoradiotherapy (CRT) with standard-dose capecitabine as neoadjuvant treatment for wild-type KRAS locally advanced rectal cancer (LARC). PATIENTS AND METHODS: Patients with wild-type KRAS, T3-4 and/or N+ LARC were randomly assigned to receive CRT with or without P (6 mg/kg). The primary end-point was pathological near-complete or complete tumor response (pNC/CR), defined as grade 3 (pNCR) or 4 (pCR) histological regression by Dworak classification (DC). RESULTS: Forty of 68 patients were randomly assigned to P + CRT and 28 to CRT. pNC/CR was achieved in 21 patients (53%) treated with P + CRT [95% confidence interval (CI) 36%-69%] versus 9 patients (32%) treated with CRT alone (95% CI: 16%-52%). pCR was achieved in 4 (10%) and 5 (18%) patients, and pNCR in 17 (43%) and 4 (14%) patients. In immunohistochemical analysis, most DC 3 cells were not apoptotic. The most common grade ≥3 toxic effects in the P + CRT/CRT arm were diarrhea (10%/6%) and anastomotic leakage (15%/4%). CONCLUSIONS: The addition of panitumumab to neoadjuvant CRT in patients with KRAS wild-type LARC resulted in a high pNC/CR rate, mostly grade 3 DC. The results of both treatment arms exceeded prespecified thresholds. The addition of panitumumab increased toxicity.

Endocavitary contact radiation therapy for ultrasonographically staged T1 N0 and T2 N0 rectal cancer.

BACKGROUND: The purpose of this study was to determine the long-term outcomes of patients undergoing endocavitary contact radiation therapy (ECR) for stage I rectal cancer. METHODS: A database of patients treated with ECR for biopsy-proven rectal adenocarcinoma from July 1986 to June 2006 was reviewed retrospectively. Only patients with primary, non-metastatic, ultrasonographically staged T1 N0 and T2 N0 cancer who had no adjuvant treatment were included. Patients received a median of 90 (range 60-190) Gy contact radiation, delivered transanally by a 50-kV X-ray tube in two to five fractions. RESULTS: Of 149 patients, 77 (40 T1, 37 T2) met the inclusion criteria. Median age was 74 (range 38-104) years, and median follow-up 69 (range 10-219) months. ECR failed in 21 patients (27 per cent) (persistent disease, four; recurrence, 17), of whom ten remained disease free after salvage therapy. The estimated 5-year disease-free survival rate was 74 (95 per cent confidence interval 63 to 83) per cent after ECR alone, and 87 (76 to 93) per cent when survival after salvage therapy for recurrence was included. CONCLUSION: ECR is a minimally invasive treatment option for early-stage rectal cancer. However, similar to other local therapies, ECR has a worse oncological outcome than radical surgery.

CPT-11 and concomitant hyperfractionated accelerated radiotherapy induce efficient local control in rectal cancer patients: results from a phase II.

Patients with rectal cancer are at high risk of disease recurrence despite neoadjuvant radiochemotherapy with 5-Fluorouracil (5FU), a regimen that is now widely applied. In order to develop a regimen with increased antitumour activity, we previously established the recommended dose of neoadjuvant CPT-11 (three times weekly 90 mg m(-2)) concomitant to hyperfractionated accelerated radiotherapy (HART) followed by surgery within 1 week. Thirty-three patients (20 men) with a locally advanced adenocarcinoma of the rectum were enrolled in this prospective phase II trial (1 cT2, 29 cT3, 3 cT4 and 21 cN+). Median age was 60 years (range 43-75 years). All patients received all three injections of CPT-11 and all but two patients completed radiotherapy as planned. Surgery with total mesorectal excision (TME) was performed within 1 week (range 2-15 days). The preoperative chemoradiotherapy was overall well tolerated, 24% of the patients experienced grade 3 diarrhoea that was easily manageable. At a median follow-up of 2 years no local recurrence occurred, however, nine patients developed distant metastases. The 2-year disease-free survival was 66% (95% confidence interval 0.48-0.83). Neoadjuvant CPT-11 and HART allow for excellent local control; however, distant relapse remains a concern in this patient population.

Transanal endoscopic microsurgery versus conventional transanal excision for patients with early rectal cancer.

OBJECTIVE: To compare transanal endoscopic microsurgery (TEMS) with conventional transanal excision (TAE) in terms of the quality of resection, local recurrence, and survival rates in patients with stage I rectal cancer. BACKGROUND: Although TEMS is often considered a superior surgical technique to TAE, it is poorly suited for excising tumors in the lower third of the rectum. Such tumors may confer a worse prognosis. METHODS: We retrospectively reviewed information on all patients with stage pT1 and pT2 rectal adenocarcinoma who underwent local excision from 1997 through mid-2006. We excluded patients with node-positive, metastatic, recurrent, previously irradiated, or snare-excised tumors. RESULTS: Our study included 42 TEMS and 129 TAE patients. We found no significant differences in patient characteristics, adjuvant therapy, tumor stage, or adverse histopathologic features. In the TAE group, 52 (40%) of tumors were <5 cm from the anal verge (AV); in the TEMS group, only 1 (2%) (P = 0.0001). Surgical margins were less often positive in the TEMS group (2%) than in the TAE group (16%) (P = 0.017). For patients with tumors > or =5 cm from the AV, the estimated 5-year disease-free survival (DFS) rate was similar between the TEMS group (84.1%) and the TAE group (76.1%) (P = 0.651). But within the TAE group, the estimated 5-year DFS rate was better for patients with tumors > or =5 cm from the AV (76.1%) vs. <5 cm from the AV (60.5%) (P = 0.029). In our multivariate analysis, the tumor distance from the anal verge, the resection margin status, the T stage, and the use of adjuvant therapy--but not the surgical technique (i.e., TEMS or TAE) itself--were independent predictors of local recurrence and DFS. CONCLUSIONS: The quality of resection is better with TEMS than with TAE. However, the apparently better oncologic outcomes with TEMS can be partly explained by case selection of lower-risk tumors of the upper rectum.

L'ultrasonographie endorectale dans les cancers du rectum [Endorectal ultrasound of rectal cancers].

Endorectal ultrasonography has become the preferred exam to assess the local extent of rectal cancers. From 1990 to 1992, we have examined 28 patients with a rectal cancer. The tumours were classified according to the TNM. The objective of this exam is to identify patients whose tumours have invaded the perirectal fat. These patients are first treated in our clinic by an accelerated hyperfractionated radiotherapy and then operated. The preoperative staging made with the endorectal ultrasound was then compared with the anatomopathologic staging. The depth of the invasion was assessed precisely in 78.5% of cases. The exam's sensitivity to detect the invasion of the perirectal fat was 96% and its specificity 75%. Lymph node involvement was accurately identified in 67.8% of cases with a sensitivity of 81% and a specificity of 50%. This short retrospective study confirms that endorectal ultrasonography is a highly accurate tool for the staging of rectal carcinoma prior to operation and hence to select the patients that can benefit from preoperative irradiation.

Development of CBCT-based prostate setup correction strategies and impact of rectal distension.

BACKGROUND: Cone-beam computed tomography (CBCT) image-guided radiotherapy (IGRT) systems are widely used tools to verify and correct the target position before each fraction, allowing to maximize treatment accuracy and precision. In this study, we evaluate automatic three-dimensional intensity-based rigid registration (RR) methods for prostate setup correction using CBCT scans and study the impact of rectal distension on registration quality. METHODS: We retrospectively analyzed 115 CBCT scans of 10 prostate patients. CT-to-CBCT registration was performed using (a) global RR, (b) bony RR, or (c) bony RR refined by a local prostate RR using the CT clinical target volume (CTV) expanded with 1-to-20-mm varying margins. After propagation of the manual CT contours, automatic CBCT contours were generated. For evaluation, a radiation oncologist manually delineated the CTV on the CBCT scans. The propagated and manual CBCT contours were compared using the Dice similarity and a measure based on the bidirectional local distance (BLD). We also conducted a blind visual assessment of the quality of the propagated segmentations. Moreover, we automatically quantified rectal distension between the CT and CBCT scans without using the manual CBCT contours and we investigated its correlation with the registration failures. To improve the registration quality, the air in the rectum was replaced with soft tissue using a filter. The results with and without filtering were compared. RESULTS: The statistical analysis of the Dice coefficients and the BLD values resulted in highly significant differences (p<10(-6)) for the 5-mm and 8-mm local RRs vs the global, bony and 1-mm local RRs. The 8-mm local RR provided the best compromise between accuracy and robustness (Dice median of 0.814 and 97% of success with filtering the air in the rectum). We observed that all failures were due to high rectal distension. Moreover, the visual assessment confirmed the superiority of the 8-mm local RR over the bony RR. CONCLUSION: The most successful CT-to-CBCT RR method proved to be the 8-mm local RR. We have shown the correlation between its registration failures and rectal distension. Furthermore, we have provided a simple (easily applicable in routine) and automatic method to quantify rectal distension and to predict registration failure using only the manual CT contours.

Primary localized rectal/pararectal gastrointestinal stromal tumors: results of surgical and multimodal therapy from the French Sarcoma group.

BACKGROUND: Rectal and pararectal gastrointestinal stromal tumors (GISTs) are rare. The optimal management strategy for primary localized GISTs remains poorly defined. METHODS: We conducted a retrospective analysis of 41 patients with localized rectal or pararectal GISTs treated between 1991 and 2011 in 13 French Sarcoma Group centers. RESULTS: Of 12 patients who received preoperative imatinib therapy for a median duration of 7 (2-12) months, 8 experienced a partial response, 3 had stable disease, and 1 had a complete response. Thirty and 11 patients underwent function-sparing conservative surgery and abdominoperineal resection, respectively. Tumor resections were mostly R0 and R1 in 35 patients. Tumor rupture occurred in 12 patients. Eleven patients received postoperative imatinib with a median follow-up of 59 (2.4-186) months. The median time to disease relapse was 36 (9.8-62) months. The 5-year overall survival rate was 86.5%. Twenty patients developed local recurrence after surgery alone, two developed recurrence after resection combined with preoperative and/or postoperative imatinib, and eight developed metastases. In univariate analysis, the mitotic index (≤5) and tumor size (≤5 cm) were associated with a significantly decreased risk of local relapse. Perioperative imatinib was associated with a significantly reduced risk of overall relapse and local relapse. CONCLUSIONS: Perioperative imatinib therapy was associated with improved disease-free survival. Preoperative imatinib was effective. Tumor shrinkage has a clear benefit for local excision in terms of feasibility and function preservation. Given the complexity of rectal GISTs, referral of patients with this rare disease to expert centers to undergo a multidisciplinary approach is recommended.

Use of limitations of radiolabeled anti-CEA antibodies and their fragments for photoscanning detection of human colorectal carcinomas.

Fifty-three patients with histologically proven carcinoma were injected with highly purified [131I]-labeled goat antibodies or fragments of antibodies against carcinoembryonic antigen (CEA). Each patient was tested by external photoscanning 4, 24, 36 and 48 h after injection. In 22 patients (16 of 38 injected with intact antibodies, 5 of 13 with F(ab')2 fragments and 1 of 2 with Fab' fragments), an increased concentration of 131I radioactivity corresponding to the previously known tumor location was detected by photoscanning 36-48 h after injection. Blood pool and secreted radioactivity was determined in all patients by injecting 15 min before scanning, [99mTc]-labeled normal serum albumin and free 99mTc04-. The computerized subtraction of 99mTc from 131I radioactivity enhanced the definition of tumor localization in the 22 positive patients. However, in spite of the computerized subtraction, interpretation of the scans remained doubtful for 12 patients and was entirely negative for 19 additional patients. In order to provide a more objective evaluation for the specificity of the tumor localization of antibodies, 14 patients scheduled for tumor resection were injected simultaneously with [131I]-labeled antibodies or fragments and with [125I]-labeled normal goat IgG or fragments. After surgery, the radioactivity of the two isotopes present either in tumor or adjacent normal tissues was measured in a dual channel scintillation counter. The results showed that the antibodies or their fragments were 2-4 times more concentrated in the tumor than in the normal tissues. In addition, it was shown that the injected antibodies formed immune complexes with circulating CEA and that the amount of immune complexes detectable in serum was roughly proportional to the level of circulating CEA.

Transanal endoscopic microsurgery resection of rectal tumors: outcomes and recommendations.

PURPOSE: Transanal endoscopic microsurgery provides a minimally invasive alternative to radical surgery for excision of benign and malignant rectal tumors. The purpose of this study was to review our experience with transanal endoscopic microsurgery to clarify its role in the treatment of different types of rectal pathology. METHODS: A prospective database documented all patients undergoing transanal endoscopic microsurgery from October 1996 through June 2008. We analyzed patient and operative factors, complications, and tumor recurrence. For recurrence analysis, we excluded patients with fewer than 6 months of follow-up, previous excisions, known metastases at initial presentation, and those who underwent immediate radical resection following transanal endoscopic microsurgery. RESULTS: Two hundred sixty-nine patients underwent transanal endoscopic microsurgery for benign (n = 158) and malignant (n = 111) tumors. Procedure-related complications (21%) included urinary retention (10.8%), fecal incontinence (4.1%), fever (3.8%), suture line dehiscence (1.5%), and bleeding (1.5%). Local recurrence rates for 121 benign and 83 malignant tumors were 5% for adenomas, 9.8% for T1 adenocarcinoma, 23.5% for T2 adenocarcinoma, 100% for T3 adenocarcinoma, and 0% for carcinoid tumors. All 6 (100%) recurrent adenomas were retreated with endoscopic techniques, and 8 of 17 (47%) recurrent adenocarcinomas underwent salvage procedures with curative intent. CONCLUSIONS: Transanal endoscopic microsurgery is a safe and effective method for excision of benign and malignant rectal tumors. Transanal endoscopic microsurgery can be offered for (1) curative resection of benign tumors, carcinoid tumors, and select T1 adenocarcinomas, (2) histopathologic staging in indeterminate cases, and (3) palliative resection in patients medically unfit or unwilling to undergo radical resection.

Perineal stapled prolapse resection for external rectal prolapse: is it worthwhile in the long-term?

BACKGROUND: Perineal stapled prolapse (PSP) resection is a novel operation for treating external rectal prolapse. However, no long-term results have been reported in the literature. This study analyses the long-term recurrence rate, functional outcome, and morbidity associated with PSP resection. METHODS: Nine consecutive patients undergoing PSP resection between 2007 and 2011 were prospectively followed. Surgery was performed by the same surgeons in a standardised technique. Recurrence rate, functional outcome, and complication grade were prospectively assessed. RESULTS: All 9 patients undergoing PSP resection were investigated. The median age was 72 years (range 25-88 years). No intraoperative complications occurred. Faecal incontinence, preoperatively present in 2 patients, worsened postoperatively in one patient (Vaizey 18-22). One patient developed new-onset faecal incontinence (Vaizey 18). The median obstructive defecation syndrome score decreased postoperatively significantly from 11 (median; range 8-13) to 5 (median; range 4-8) (p < 0.005). At a median follow-up of 40 months (range 14-58 months), the prolapse recurrence rate was 44 % (4/9 patients). CONCLUSIONS: The PSP resection is a fast and safe procedure associated with low morbidity. However, the poor long-term functional outcome and the recurrence rate of 44 % warrant a cautious patient selection.

Dukes B colorectal cancer: distinct genetic categories and clinical outcome based on proximal or distal tumor location.

PURPOSE: The aim of this study was to determine whether tumor location proximal or distal to the splenic flexure is associated with distinct molecular patterns and can predict clinical outcome in a homogeneous group of patients with Dukes B (T3-T4, N0, M0) colorectal cancer. It has been hypothesized that proximal and distal colorectal cancer may arise through different pathogenetic mechanisms. Although p53 and Ki-ras gene mutations occur frequently in distal tumors, another form of genomic instability associated with defective DNA mismatch repair has been predominantly identified in the proximal colon. To date, however, the clinical usefulness of these molecular characteristics remains unproven. METHODS: A total of 126 patients with a lymph node-negative sporadic colon or rectum adenocarcinoma were prospectively assessed with the endpoint of death by cancer. No patient received either radiotherapy or chemotherapy. p53 protein was studied by immunohistochemistry using DO-7 monoclonal antibody, and p53 and Ki-ras gene mutations were detected by single strand conformation polymorphism assay. RESULTS: During a mean follow-up of 67 months, the overall five-year survival was 70 percent. Nuclear p53 staining was found in 57 tumors (47 percent), and was more frequent in distal than in proximal tumors (55 vs. 21 percent; chi-squared test, P < 0.001). For the whole group, p53 protein expression correlated with poor survival in univariate and multivariate analysis (log-rank test, P = 0.01; hazard ratio = 2.16; 95 percent confidence interval = 1.12-4.11, P = 0.02). Distal colon tumors and rectal tumors exhibited similar molecular patterns and showed no difference in clinical outcome. In comparison with distal colorectal cancer, proximal tumors were found to be statistically significantly different on the following factors: mucinous content (P = 0.008), degree of histologic differentiation (P = 0.012), p53 protein expression, and gene mutation (P = 0.001 and 0.01 respectively). Finally, patients with proximal tumors had a marginally better survival than those with distal colon or rectal cancers (log-rank test, P = 0.045). CONCLUSION: In this series of Dukes B colorectal cancers, p53 protein expression was an independent factor for survival, which also correlated with tumor location. Eighty-six percent of p53-positive tumors were located in the distal colon and rectum. Distal colon and rectum tumors had similar molecular and clinical characteristics. In contrast, proximal neoplasms seem to represent a distinct entity, with specific histopathologic characteristics, molecular patterns, and clinical outcome. Location of the neoplasm in reference to the splenic flexure should be considered before group stratification in future trials of adjuvant chemotherapy in patients with Dukes B tumors.

Der Radioimmunoassay zur Ermittlung des carcinoembryonalen Antigens (CEA), seine Bedeutung und Limitierung während der postoperativen Kontrollperiode von Patienten mit colorectalem Carcino

Carcinoembryonic antigen (CEA) is a tumor marker defined by specific heterologous antisera. Elevated levels of circulating CEA can be detected by radioimmunoassay in most cases of colorectal carcinoma, depending on the degree of tumor spread. The fact that elevation of CEA level can also be observed in other types of carcinomas and in several nonmalignant conditions greatly limits the value of the CEA test for the early diagnosis of colorectal carcinomas. Repeated CEA measurements and their critical interpretation, however, appear to be of importance after tumor resection for the detection of tumor recurrence during the postoperative follow-up period.