The Analgesic Effect of Magnetic Acupressure During Bone Marrow Aspiration and Biopsy Procedure in Cancer Patients: A Randomized, Blinded, Placebo Controlled Trial.

Bone marrow aspiration and biopsy (BMAB) is one of the most frequently performed and painful procedures in cancer patients. Magnetic acupressure has been used to reduce pain in patients in China. Our study was designed to study the efficacy of magnetic acupressure in reducing pain in cancer patients undergoing BMAB.

Patients eligible for this IRB approved study had cancer, had a BMAB planned, and had not previously had acupuncture or acupressure. They were stratified by the number of prior BMAB they had experienced and randomly assigned to receive either magnetic acupressure at large intestine 4 point or at a non-acupuncture point (placebo) located in the proximal fourth interosseus space of the hand. All BMAB procedures were done by one operator (JS) and all acupressure was performed by one experienced operator (TB). All patients as well as the BMAB operator and data collector were blinded to treatment assignment. A visual analog score (VAS) was used to measure the patient's baseline pre-BMAB pain and the pain associated with the BMAB procedure. The acupressure operator was blinded to baseline pain scores and the pain associated with the BMAB by having the patient complete a form which was seen only by an independent data collector. The differences in VAS associated with the BMAB in the real versus placebo acupressure cohorts were compared to determine the analgesic efficacy of magnetic acupressure.

From 5/08 to 6/09, 77 cancer patients (47 male, 63 Caucasian, with a median age: 56 yrs, range: 21-80) undergoing BMAB at the Johns Hopkins Kimmel Sidney Comprehensive Cancer Center were enrolled in the study. Thirty-seven patients were randomized to the intervention arm and 40 to the control arm. Thirty-one patients (84%) in the intervention arm and 30 patients (75%) in the control arm had more than 1 BMAB prior to this study (p=0.34). Gender, analgesic or anxiolytic medications intake within 12 hours of BMAB and the pain score before BMAB were well balanced between two arms. The primary outcome was patient rated VAS pain score (0 to 10) during BMAB assessed after the procedure. Only one patient (2.7%) in the intervention arm experienced severe pain (VAS≥7) compared to 8 patients (20%) in the control arm (p=0.03, two- tailed Fisher's exact test). Using a multivariate logistic regression analysis to adjust for the number of BMAB patients had prior to this study, the odds of patients experiencing severe pain during BMAB procedure was 8.4 times (95% CI: 0.98-71.9) higher in the control arm versus the intervention arm. Forty-five percent of patients in each arm requested acupressure for future BMABs. No significant side effects or discomforts related to acupressure were reported by patients in either arm.

These results suggest that magnetic acupressure significantly reduces the proportion of patients experiencing severe pain during BMAB. As acupressure requires minimal training and expense and was not associated with adverse events, it could be readily incorporated as a treatment option in this patient population. A larger, multi-centered, randomized, placebo controlled trial is planned to confirm these observations.

No relevant conflicts of interest to declare.