Five-year follow-up of the Medical Research Council CLASICC trial of laparoscopically assisted versus open surgery for colorectal cancer.

INTRODUCTION: The UK Medical Research Council CLASICC trial assessed the safety and efficacy of laparoscopically assisted surgery in comparison with open surgery for colorectal cancer. The results of the 5-year follow-up analysis are presented. METHODS: Five-year outcomes were analysed and included overall and disease-free survival, and local, distant and wound/port-site recurrences. Two exploratory analyses were performed to evaluate the effect of age (70 years or less, or more than 70 years) on overall survival between the two groups, and the effect of the learning curve. RESULTS: No differences were found between laparoscopically assisted and open surgery in terms of overall survival, disease-free survival, and local and distant recurrence. Wound/port-site recurrence rates in the laparoscopic arm remained stable at 2.4 per cent. Conversion to open operation was associated with significantly worse overall but not disease-free survival, which was most marked in the early follow-up period. The effect of surgery did not differ between the age groups, and surgical experience did not impact on the 5-year results. CONCLUSION: The 5-year analyses confirm the oncological safety of laparoscopic surgery for both colonic and rectal cancer. The use of laparoscopic surgery to maximize short-term outcomes does not compromise the long-term oncological results. REGISTRATION NUMBER: ISRCTN74883561 (http://www.controlled-trials.com).

Tree mortality following partial harvests is determined by skidding proximity.

Recently developed structural retention harvesting strategies aim to improve habitat and ecological services provided by managed forest stands by better emulating natural disturbances. The potential for elevated mortality of residual trees following such harvests remains a critical concern for forest managers, and may present a barrier to more widespread implementation of the approach. We used a harvest chronosequence combined with dendrochronological techniques and an individual-based neighborhood analysis to examine the rate and time course of residual-tree mortality in the first decade following operational partial "structural retention" harvests in the boreal forest of Ontario, Canada. In the first year after harvest, residual-tree mortality peaked at 12.6 times the preharvest rate. Subsequently, mortality declined rapidly and approached preharvest levels within 10 years. Proximity to skid trails was the most important predictor both of windthrow and standing death, which contributed roughly equally to total postharvest mortality. Local exposure further increased windthrow risk, while crowding enhanced the risk of standing mortality. Ten years after harvest, an average of 10.5% of residual trees had died as a result of elevated postharvest mortality. Predicted cumulative elevated mortality in the first decade after harvest ranged from 2.4% to 37% of residual trees across the observed gradient of skid trail proximity, indicating that postharvest mortality will remain at or below acceptable rates only if skidding impacts are minimized. These results represent an important step toward understanding how elevated mortality may influence stand dynamics and habitat supply following moderate-severity disturbances such as partial harvests, insect outbreaks, and windstorms.