Regional anesthesia and analgesia in cancer care: is it time to break the bad news?

The Intersection of Regional Anesthesia and Cancer Progression: A Theoretical Framework

The surgical stress and inflammatory response and volatile anesthetic agents have been shown to promote tumor metastasis in animal and in-vitro studies. Regional neuraxial anesthesia protects against these effects by decreasing the surgical stress and inflammatory response and associated changes in immune function in animals. However, evidence of a similar effect in humans remains equivocal due to the high variability and retrospective nature of clinical studies and difficulty in directly comparing regional versus general anesthesia in humans. We propose a theoretical framework to address the question of regional anesthesia as protective against metastasis.

This theoretical construct views the immune system, circulating tumor cells, micrometastases, and inflammatory mediators as distinct populations in a highly connected system. In ecological theory, highly connected populations demonstrate more resilience to local perturbations but are prone to system-wide shifts compared with their poorly connected counterparts. Neuraxial anesthesia transforms the otherwise system-wide perturbations of the surgical stress and inflammatory response and volatile anesthesia into a comparatively local perturbation to which the system is more resilient. We propose this framework for experimental and mathematical models to help determine the impact of anesthetic choice on recurrence and metastasis and create therapeutic strategies to improve cancer outcomes after surgery.

Effects of propofol and sevoflurane on tumor killing activity of peripheral blood natural killer cells in patients with gastric cancer

Objective

This study aimed to investigate the effects of propofol and sevoflurane on cytotoxicity of natural killer (NK) cells in patients with gastric cancer.

Methods

Patients with gastric cancer were anesthetized by propofol or sevoflurane. Peripheral blood NK cells were isolated and co-cultured with BGC-823 gastric cancer cell culture supernatant, and the rate of apoptosis and effector molecules were analyzed by flow cytometry. Effects of propofol and sevoflurane on NK cell function and SMAD4 protein expression were investigated.

Results

Cytotoxicity of NK cells in patients with gastric cancer was inhibited before surgery, but it was enhanced in patients who were anesthetized by propofol compared with those who had sevoflurane. In vitro co-culture with BGC-823 cells significantly inhibited the cytotoxicity of NK cells, which was abolished by treatment of propofol or transforming growth factor (TGF)-β1. SMAD4 protein expression in the NK cell nucleus was significantly downregulated by TGF-β1 treatment and BGC-823 supernatant co-culture, and this expression could be restored by propofol.

Conclusions

Cytotoxicity of NK cells in patients with gastric cancer is low, but it can be promoted by propofol. Propofol regulates cytotoxicity in NK cells by promoting SMAD4, thereby affecting cellular function.

Opioid free onco-anesthesia: Is it time to convict opioids? A systematic review of literature

The epidemic of opioid crisis started getting recognised as a public health emergency in view of increasing opioid-related deaths occurring due to undetected respiratory depression. Prescribing opioids at discharge has become an independent risk factor for chronic opioid use, following which, prescription practices have undergone a radical change. A call to action has been voiced recently to end the opioid epidemic although with the pain practitioners still struggling to make opioids readily available. American Society of Anesthesiologist (ASA) has called for reducing patient exposure to opioids in the surgical setting. Opioid sparing strategies have emerged embracing loco-regional techniques and non-opioid based multimodal pain management whereas opioid free anesthesia is the combination of various opioid sparing strategies culminating in complete elimination of opioid usage. The movement away from opioid usage perioperatively is a massive but necessary shift in anesthesia which has rationalised perioperative opioid usage. Ideal way moving forward would be to adapt selective low opioid effective dosing which is both procedure and patient specific while reserving it as rescue analgesia, postoperatively. Many unknowns persist in the domain of immunologic effects of opioids, as complex interplay of factors gets associated during real time surgery towards outcome. At present it would be too premature to conclude upon opioid-induced immunosuppression from the existing evidence. Till evidence is established, there are no recommendations to change current clinical practice. At the same time, consideration for multimodal opioid sparing strategies should be initiated in each patient undergoing surgery.

Anesthetic effect of propofol combined with remifentanil or sevoflurane anesthesia on patients undergoing radical gastrectomy

Anesthetic effect of propofol combined with remifentanil or sevoflurane intravenous anesthesia on patients undergoing radical gastrectomy was evaluated. The clinical data of 516 cancer patients who received radical gastrectomy in the First Bethune Hospital of Jilin University between January 2011 and December 2017 were retrospectively analyzed. In total 203 patients with propofol combined with remifentanil anesthesia were used as group A, and 313 patients with propofol combined with sevoflurane anesthesia as group B. The changes of respiration and circulation were analyzed at the time of entering the operating room (t0), the beginning of the operation (t1), 10 min after the beginning of the operation (t2) and 10 min after operation (t3). The onset time of anesthesia, the total time of operation, the time of waking up after operation and the time of leaving the operating room were analyzed. The effects of sedation and amnesia were evaluated, and the occurrence of adverse reactions were recorded. The inhibition of circulation and respiration was more obvious at t1 and t2 in group A when compared to group B (P<0.05), and the respiration and circulation in group B was more stable than that in group A (P<0.001). Patients' sedation scores in group A were lower than those in group B, and the difference was statistically significant (P<0.05); there were 56 (27.59%) patients and 30 (9.58%) patients with postoperative pain in group A and group B, respectively (P<0.001). The application of propofol combined with sevoflurane in the anesthesia of patients undergoing radical gastrectomy can make the respiration and circulation more stable, and reduce the incidence of postoperative pain and adverse reactions.