Mats Enlund1, Anders Berglund2, Rebecca Ahlstrand3, Jakob Walldén4, Johan Lundberg5,6, Fredrik Wärnberg7, Andreas Ekman8, Nina Sjöblom Widfeldt9, Anna Enlund1,7, Leif Bergkvist1. 1. Center for Clinical Research, Västmanland Hospital, Uppsala University, Västerås, Sweden. 2. Epistat, Uppsala, Sweden. 3. Department of Anesthesia & Intensive Care, University Hospital, Örebro, Sweden. 4. Department of Surgical and Perioperative Sciences, Anesthesiology and Intensive Care Medicine (Sundsvall), Umeå University, Sundsvall, Sweden. 5. Department of Anesthesiology and Intensive Care, Lund University, Lund, Sweden. 6. Skane University Hospital, Lund, Sweden. 7. Department of Surgical Sciences, Uppsala University, Uppsala, Sweden. 8. Kalmar Hospital, Kalmar, Sweden. 9. Södra Älvsborg Hospital, Borås, Sweden.
Abstract
BACKGROUND: Retrospective studies indicate that the choice of anesthetic can affect long-term cancer survival. Propofol seems to have an advantage over sevoflurane. However, this is questioned for breast cancer. We gathered a large cohort of breast cancer surgery patients from seven Swedish hospitals and hypothesized that general anesthesia with propofol would be superior to sevoflurane anesthesia regarding long-term breast cancer survival. METHODS: We identified all patients who were anaesthetized for breast cancer surgery between 2006 and 2012. The patients were matched to the Swedish Breast Cancer Quality Register, to retrieve tumor characteristics, prognostic factors, and adjuvant treatment as well as date of death. Overall survival between patients undergoing sevoflurane and propofol anesthesia was analyzed with different statistical approaches: (a) multiple Cox regression models adjusted for demographic, oncological, and multiple control variables, (b) propensity score matching on the same variables, but also including the participating centers as a cofactor in a separate analysis. RESULTS: The database analysis identified 6305 patients. The 5-year survival rates were 91.0% and 81.8% for the propofol and sevoflurane group, respectively, in the final model (P = .126). Depending on the statistical adjustment method used, different results were obtained, from a non-significant to a "proposed" and even a "determined" difference in survival that favored propofol, with a maximum of 9.2 percentage points higher survival rate at 5 years (hazard ratio 1.46, 95% CI 1.10-1.95). CONCLUSIONS: It seems that propofol may have a survival advantage compared with sevoflurane among breast cancer patients, but the inherent weaknesses of retrospective analyses were made apparent.
BACKGROUND: Retrospective studies indicate that the choice of anesthetic can affect long-term cancer survival. Propofol seems to have an advantage over sevoflurane. However, this is questioned for breast cancer. We gathered a large cohort of breast cancer surgery patients from seven Swedish hospitals and hypothesized that general anesthesia with propofol would be superior to sevoflurane anesthesia regarding long-term breast cancer survival. METHODS: We identified all patients who were anaesthetized for breast cancer surgery between 2006 and 2012. The patients were matched to the Swedish Breast Cancer Quality Register, to retrieve tumor characteristics, prognostic factors, and adjuvant treatment as well as date of death. Overall survival between patients undergoing sevoflurane and propofol anesthesia was analyzed with different statistical approaches: (a) multiple Cox regression models adjusted for demographic, oncological, and multiple control variables, (b) propensity score matching on the same variables, but also including the participating centers as a cofactor in a separate analysis. RESULTS: The database analysis identified 6305 patients. The 5-year survival rates were 91.0% and 81.8% for the propofol and sevoflurane group, respectively, in the final model (P = .126). Depending on the statistical adjustment method used, different results were obtained, from a non-significant to a "proposed" and even a "determined" difference in survival that favored propofol, with a maximum of 9.2 percentage points higher survival rate at 5 years (hazard ratio 1.46, 95% CI 1.10-1.95). CONCLUSIONS: It seems that propofol may have a survival advantage compared with sevoflurane among breast cancerpatients, but the inherent weaknesses of retrospective analyses were made apparent.