Anesthesia and Cancer Recurrence : Context for Divergent Study Outcomes

The metastatic process is highly inefficient--very few of the many cells that migrate from the primary tumour successfully colonize distant sites. One proposed mechanism to explain this inefficiency is provided by the cancer stem cell model, which hypothesizes that micrometastases can only be established by tumour stem cells, which are few in number. However, recent in vitro and in vivo observations indicate that apoptosis is an important process regulating metastasis. Here we stress that the inhibition of cell death, apart from its extensively described function in primary tumour development, is a crucial characteristic of metastatic cancer cells.

Although early reports on laparoscopy-assisted colectomy (LAC) in patients with colon cancer suggested that it reduces perioperative morbidity, its influence on long-term results is unknown. Our study aimed to compare efficacy of LAC and open colectomy (OC) for treatment of non-metastatic colon cancer in terms of tumour recurrence and survival. From November, 1993, to July, 1998, all patients with adenocarcinoma of the colon were assessed for entry in this randomised trial. Adjuvant therapy and postoperative follow-up were the same in both groups. The main endpoint was cancer-related survival. Data were analysed according to the intention-to-treat principle. 219 patients took part in the study (111 LAC group, 108 OC group). Patients in the LAC group recovered faster than those in the OC group, with shorter peristalsis-detection (p=0.001) and oral-intake times (p=0.001), and shorter hospital stays (p=0.005). Morbidity was lower in the LAC group (p=0.001), although LAC did not influence perioperative mortality. Probability of cancer-related survival was higher in the LAC group (p=0.02). The Cox model showed that LAC was independently associated with reduced risk of tumour relapse (hazard ratio 0.39, 95% CI 0.19-0.82), death from any cause (0.48, 0.23-1.01), and death from a cancer-related cause (0.38, 0.16-0.91) compared with OC. This superiority of LAC was due to differences in patients with stage III tumours (p=0.04, p=0.02, and p=0.006, respectively). LAC is more effective than OC for treatment of colon cancer in terms of morbidity, hospital stay, tumour recurrence, and cancer-related survival.

Surgical resection remains the best option for long-term survival in many solid tumors. Surgery can, however, lead to tumor cell release into the circulation. Data have suggested differential effects of anesthetic agents on cancer cell growth. This retrospective analysis investigated the association of anesthetic technique with long-term survival in patients presenting for elective surgery in a comprehensive cancer center over 3 yr.