Effect of preoperative fever-range whole-body hyperthermia on immunological markers in patients undergoing colorectal cancer surgery
Previous studies have demonstrated beneficial immunological effects of fever-range whole-body hyperthermia (FR-WBH) as an adjunct to non-surgical cancer therapy. We conducted a study of preoperative FR-WBH in patients undergoing colorectal cancer surgery to evaluate perioperative, hyperthermia-induced immunomodulation.
The trial was conducted as a subject-blinded, controlled, randomized study. Subjects in the FR-WBH group (n=9) were treated with FR-WBH before operation under propofol sedation; the target core temperature was 39 (0.5)°C with 1 h warming and 2 h plateau phase. Subjects in the control group (n=9) were treated with propofol sedation only. Blood samples were acquired before and after treatment, after operation, and 24, 48 h, and 5 days after the end of surgery. The following parameters were measured: lipopolysaccharide (LPS)-induced tumour necrosis factor (TNF)-α, procalcitonin (PCT), interleukin (IL)-6/10, heat shock proteins (HSPs) 60, 70, and 90, human leucocyte antigen-DR (HLA-DR), and LPS-binding protein (LBP).
HSPs were increased in the FR-WBH group after treatment [HSP60, 48 h postop: 143 (41)% vs 89 (42)%, P=0.04; HSP90, postop: 111 (33)% vs 64 (31)%, P=0.04; HSP70: P=0.40; FR-WBH vs control, P-values for area under the level/time curve]. TNF-α levels were elevated after surgery in the control group and remained near baseline in the FR-WBH group [24 h postop: 73 (68)% vs 151 (72)%, P=0.04]. PCT increased in both groups 24 h after surgery; in the control group, this increase was significantly higher (P=0.02). There were no significant differences for IL, HLA-DR, or LBP.
The immune system to react to surgical stress, as measured by a panel of laboratory indicators, might be improved by preoperative FR-WBH.
- Therapeutic hyperthermia might have beneficial immunological effects as an adjunct to cancer surgery.
- The effects of preoperative hyperthermia on a panel of immune system indicators were studied in patients undergoing cancer surgery.
- Two hours of hyperthermia before surgery had potentially beneficial effects on the immune responses to the stress of cancer surgery in this small pilot study.
After surgical cancer therapy, immunological host defence mechanisms of patients are often significantly impaired. This immunological impairment can increase the likelihood of postoperative infections, delay postoperative recovery, and promote metastatic growth.1,2 Perioperatively, immunomodulation is caused to some degree by a stress response to surgical trauma. However, animal and human experiments have demonstrated additional contributing immunosuppressive effects of general anaesthesia. Several inhalation and i.v. drugs have immunomodulatory effects,3,4 and opioids are currently seen as the primary culprits.5,6 Regional anaesthesia, alone or as an adjunct to general anaesthesia, would thus be an obvious choice to avoid or reduce opioid-induced immunosuppression.7 Minimization of surgical trauma, preservation of normothermia, and avoidance of allogeneic blood transfusions are other evidence-based approaches.8 However, the general problem of perioperative immunosuppression remains mostly unresolved.
Induction of fever-range core temperatures in patients has been used as supportive oncological therapy in combination with radiotherapy and/or chemotherapy. The American Cancer Society mentions fever-range whole-body hyperthermia (FR-WBH) as a mostly experimental technique intended to boost the activity of the immune system.9 Several studies have demonstrated beneficial immunological effects of FR-WBH, such as increased survival in experimental sepsis,10 induction of immunostimulatory heat shock proteins (HSPs), monocyte stimulation,11 and improved immunocompetence during radiotherapy/chemotherapy.12
We performed the present study to investigate if preoperative FR-WBH can enhance perioperative immunocompetence in a subject-blinded, controlled, randomized study.
The study was approved by the research ethics committee of the Medical University of Vienna as medical device study (Ref: 16/2009) and registered at Clinicaltrials.gov (Ref: NCT00876954). After obtaining written informed consent, 18 subjects were included in the study. Inclusion criteria were age of 18–75 yr and undergoing curative, colorectal cancer surgery. Exclusive criteria included pregnancy, ongoing immunosuppressive treatment, immunosuppressive treatment in the last 3 months, ongoing chemotherapy, acute infections, or palliative surgical treatment. The trial was conducted as a subject-blinded, controlled, randomized study.
Whole-body hyperthermia system
Over the last decade, patient warming with infrared radiation has been established as a standard procedure for FR-WBH treatment. FR-WBH systems differ with regard to the spectrum of infrared radiation used and the area of application (front or back of the patient). The HECKEL HT-3000 (Heckel medizintechnik GmbH, Esslingen, Germany), used in the present study (Fig. 1), uses water-filtered infrared radiation (wIRA) delivered by four wIRA emitters to the chest, and two heating elements for warming the air under the tent-like canopy.
Heckel HT-3000 whole-body hyperthermia device. The four water-filtered infrared emitters and the tent-like structure enclosing a regular patient bed are displayed.
Subjects were transferred to the preoperative holding area ∼3.5 h before the scheduled start of surgery. In the preoperative holding area, which doubles as the postoperative recovery unit, subjects were first moved to a bed with the warming device attached, and heart rate, electrocardiography, oxygen saturation, mean arterial pressure, and core temperature via a rectal probe were monitored. After the start of sedation with propofol (3–5 mg kg−1 h−1), an opaque envelope containing a computer-generated randomization list was opened and treatment allocation was revealed. In the control group, only the heating elements for warming the air under the canopy were activated to avoid accidental hypothermia during sedation. In the FR-WBH group, all four wIRA emitters and the air heaters were activated. The core temperature of the hyperthermia group was raised to 39.0°C for a duration of 2 h. Once 39.0°C was reached, the wIRA emitters were turned off, and were turned on again if temperature decreased below 39.0°C.
Oxygen saturation, mean arterial pressure, and heart rate were registered at 5 min intervals. Isotonic crystalloid solution (Elo-mel isoton, Fresenius Kabi, Graz, Austria) was administered by continuous infusion during control and hyperthermia treatment (5–10 ml kg−1 h−1). In both groups, after treatment and during surgery, normothermia was maintained with forced air (BairHugger, Arizant, Eden Prairie, MN, USA) until arrival in the postoperative recovery unit. Anaesthesia was induced with fentanyl (1–3 µg kg−1), propofol (2–3 mg kg−1), and rocuronium (0.6 mg kg−1) and maintained with sevoflurane (1.5–2.0%) and fentanyl to keep mean arterial pressure within ±20% of the preinduction value according to a standardized protocol.
Blinding of researchers during treatment was not possible due to safety concerns as close control of core temperature and other vital parameters was paramount. However, subjects, surgeons, attending anaesthesiologists, and laboratory personnel were blinded to group assignment.
To evaluate immunomodulation, the following parameters were assessed: lipopolysaccharide (LPS)-induced tumour necrosis factor (TNF)-α, procalcitonin (PCT), interleukin (IL)-6, IL-10, HSPs 60, 70, and 90, and human leucocyte antigen (HLA)-DR. Blood samples were obtained: (i) before and (ii) after study treatment; (iii) after surgery; (iv) 24, (v) 48 h, and (vi) 5 days after surgery.
Quality of Recovery questionnaire
Twenty-four hours after surgery, the Quality of Recovery (QoR)-40 questionnaire for the quality of recovery after anaesthesia was assessed. The score ranges from 40 to 200, with higher values representing better quality of recovery. Five clinically relevant dimensions are derived, which encompass most aspects of postoperative recovery. The dimensions are emotional state, physical comfort psychological support, physical independence, and pain.13
Each blood sample consisted of 14 ml collected into a heparinized blood collection tube. After removing 100 µl for TNF-α and HLA-DR measurements, the blood was centrifuged (2500g, 10 min), the supernatant was removed, and serum samples were stored at −80°C for later analysis of PCT, HSPs, and other cytokines.
Heat shock proteins 60, 70, and 90
Stressgen® and Assay Designs® ELISA kits (Enzo Life Sciences, Farmingdale, NY, USA), and a Wallac Victor 3 V microplate reader (PerkinElmer Life Sciences, Boston, MA, USA) were used for HSP measurements.
Immediately after blood sampling, 50 µl of fresh whole blood was mixed with 500 μl of LPS solution (0.5 ng ml−1) at a clean bench. The mixture was then incubated in a water bath at 37°C for 4 h. After centrifugation, the supernatant was frozen at −80°C and measured with a standardized kit (Milenia® QuickLine TNF-α ex vivo, Milenia Biotec GmbH, Gießen, Germany) at a later date.
Human leucocyte antigen-DR
Immediately after blood sampling, 50 μl of whole blood was mixed with 20 μl of FITC Mouse Anti-Human HLA-DR (BD Pharmingen™, Franklin Lakes, NJ, USA). After incubation for 30 min at room temperature, 450 μl of BD FACS Lysing solution (BD Pharmingen™) was added to lyse red blood cells, and the sample was incubated for 30 min at room temperature. HLA-DR expression was measured by flow cytometric analysis on a FACS Cytomics FC500 (Becton Dickinson, San Jose, CA, USA).
Cytokine analysis [IL-6, IL-10, TNF-α, LPS-binding protein (LBP)] was performed using enzyme-linked immunoassay kits (DPC/Siemens Healthcare Diagnostic, Eschborn, Germany). PCT levels were measured by a fully automatic, multi-channel analyser using electrochemiluminescence technology (Cobas e 411, Roche Diagnostics Limited, Burgess Hill, UK). TNF-α was measured additionally as a validation with Siemens DPC; values in the paper are from the Milenia® QuickLine TNF-α ex vivo measurements.
As data of the immunomodulatory effect of preoperative therapeutic hyperthermia were not available at the time of protocol design, sample size estimation relied on data of perioperative, LPS-induced TNF-α levels in another context.14 Assuming a slightly larger standard deviation for both groups of 30%, a sample size of eight subjects per group was calculated for a difference of 30% with an α-error of 0.05 and a power (1−β error) of 90%. To account for a 10% dropout of subjects, who might not be able to tolerate sedation, hyperthermia treatment, or both, nine subjects per group were included in the study.
As primary analysis, the area under the variable–time curve (AUC) per subject for each variable was calculated and compared using Student’s t-test. Differences between treatment groups for variables over time were assessed by analysis of variance (ANOVA) for repeated measurements with group as the between-subject factor and time as the within-subject factor. If a significant difference between the groups was detected, Fisher’s least significant differences contrast was performed to assess differences at individual time points. The preoperative baselines of all parameters subsequently compared as percentage of baseline were initially compared using Student’s t-test between the groups to exclude any a prioriimbalances as sensitivity analysis. All immunological parameters except IL-10 were standardized to the preoperative baseline (i.e. before treatment=100%); IL-10 was below the limit of detection before operation. All data are presented as mean (SD), unless otherwise specified. PASW 18.0.3 (IBM, Armonk, NY, USA) was used for all statistical analysis; P<0.05 was considered statistically significant.
All enrolled subjects (n=18) completed the study. Patient characteristic, morphometric, anaesthesiological, and surgical data are displayed in Table 1. The core temperature of 38.5°C was reached in 71.2 (18.4) min; the mean peak temperature was 39.4 (0.4)°C; the mean duration of hyperthermia treatment was 132 (16.2) min.
|Control (n=9)||Hyperthermia (n=9)|
|Age (yr)||59.1 (46–69)||56.4 (45–72)|
|Weight (kg)||77.1 (12.8)||74.0 (8.0)|
|Height (cm)||173 (7.3)||172.0 (6.6)|
|BMI (kg m−2)||25.6 (3.8)||25.1 (3.1)|
|Propofol (mg kg−1 h−1)||5.6 (1.4)||5.5 (1.3)|
|Crystalloid (ml)||667 (240)||2140 (210)|
|Duration of surgery (min)||164 (32)||179 (60)|
|Length of hospital stay (days)||10.2 (1.7)||10.0 (3.5)|
PCT increased in both groups 24 h after surgery (time points 4–6); in the control group, this increase was significantly higher than in the FR-WBH group (P=0.02; Fig. 6).