A Meta-Analysis to Determine the Effect of Primary Tumor Resection for Stage IV Colorectal Cancer with Unresectable Metastases on Patient Survival

Background

Approximately 20 % of patients diagnosed with colorectal cancer will have distant metastases at first presentation (stage IV disease). The effect of removing the primary tumor on survival for patients with stage IV disease with unresectable metastases remains unclear. To address this a meta-analysis of all studies comparing primary tumor resection with chemotherapy alone in cases of stage IV colorectal cancer with unresectable metastases was performed.

Methods

A comprehensive search for published studies examining the effect of primary tumor resection in the setting of colorectal cancer with unresectable metastases was performed. Each study was reviewed and data extracted. Random-effects methods were used to combine data.

Results

There were 21 studies including a total of 44,226 patients that met the inclusion criteria. Resection of the primary tumor in patients with unresectable metastases compared with chemotherapy alone was associated with a lower mortality risk (OR 0.28; 95 % CI 0.165–0.474; P < 0.001), translating into a difference in mean survival of 6.4 months in favor of resection (95 % CI 5.025–7.858, P < 0.001). Patients who underwent resection of the primary tumor were more likely to have liver metastasis only (OR 1.551; 95 % CI 1.247–1.929; P < 0.001), were less likely to have ≥2 metastasis (OR 0.653; 95 % CI 0.508–0.839; P = 0.001), and were less likely to have rectal cancer (OR 0.495; 95 % CI 0.390–0.629; P < 0.001). There was significant cross-study heterogeneity.

Conclusions

Resection of the primary tumor may confer a survival advantage in stage IV colorectal cancer with unresectable metastases but significant selection bias exists in current studies. Randomized controlled trials are essential to validate these findings.     

Preoperative versus Postoperative Radiotherapy for Rectal Cancer in a Decision Analysis and Outcome Prediction Model

Purpose

Reduction of local recurrences has been achieved by radiotherapy, but also by improved surgical technique (total mesorectal excision). Radiotherapy has adverse effects and cannot exceed local dose limits. Neoadjuvant radiotherapy may result in overtreatment. We aimed to define the minimum local benefit that would have to be postulated for radiotherapy in order to bring a benefit to the overall cohort. We hypothesized that saving radiotherapy as treatment for a subset of patients with high-risk tumors and local recurrences improves the outcome of the overall cohort. We sought to simulate preoperative versus postoperative radiotherapy in theoretical decision analysis model based on published recurrence rates, with overall survival being the primary end point.

Methods

Computerized literature search for studies published between 1996 and 2011, supplemented by manual review of the retrieved reference lists.

Results

Postoperative radiotherapy evolved as preferred strategy with cure rates of 65.6?% vs. 63.7?% for postoperative and neoadjuvant radiotherapy, respectively, and a decrease of radiation exposure to 42.9?% of the cohort. The system was sensitive to (1) the fraction of stage I cancers included in the cohort, (2) the difference between local recurrence rates (LRR) for neoadjuvant radiotherapy, adjuvant radiotherapy, or surgery-only approach, and (3) the compliance with the postoperative radiotherapy. If the surgery-only recurrence was set to the published 10?%, 13?%, and 27?%, respectively, adjuvant radiotherapy had to achieve LRR below the threshold values of 6.3?%, 8.5?%, and 18.3?% to reverse the impact of compliance.

Conclusions

Radiotherapy only improves cancer-specific survival of the cohort if there is a large difference in LRR with versus without it. Routine treatment may therefore be inferior to a tailored radiotherapy regimen.     

Laparoscopic resection of curable colon and rectal cancer: an evidence-based review

The initial enthusiastic application of laparoscopic techniques to colorectal surgical procedures was tempered in the early 1990s by reports of tumor implants in the laparoscopic incisions. Substantial evidence has accumulated, including evidence from randomized controlled trials, to support that laparoscopic resection results in oncologic outcomes similar to open resection, when performed by well-trained, experienced surgeons. This review was developed in conjunction with guidelines published by the Society of American Gastrointestinal and Endoscopic Surgeons. Data from the surgical literature concerning laparoscopic resection of curable colorectal cancer was evaluated regarding diagnostic evaluation, preoperative preparation, operative techniques, prevention of tumor implants, and training and experience. Recommendations are accompanied by an assessment of the level of supporting evidence available at the time of the development of the guidelines.