Abstract P5-22-04: Efficacy of thoracic paravertebral block for reducing acute post-mastectomy pain

Background: Mastectomy is associated with acute and chronic postoperative pain. This study investigated the efficacy of thoracic paravertebral block (TPB) compared to local anesthetic of surgical wound (LASW) in breast cancer patients undergoing mastectomy.

Methods: This phase 3, randomized controlled, single blind, parallel arms and superiority clinical trial aimed to evaluate the efficacy of TPB compared to LASW on acute pain at rest and motion at 24 hours post-mastectomy, measured by a visual analog scale (VAS). The study size of 60 patients is determined to have 90% power to detect a difference of 20% in acute pain in favor of TPB. In TPB group use of ultrasound was mandatory to guide puncture of intervertebral space T3 for infiltrating 0.5% bupivacaine at dose of 1.5 mg/kg. In LASW group was used bupivacaine 0.5% at dose of 1.5mg/kg on subcutaneous tissue of surgical area. VAS was used to measure surgical pain at rest and motion in 2,4,6,12 and 24 hours post-operatives for both groups. Trial Registry: ClinicalTrials.gov; Identifier:NCT02609321.

Findings: From 08-2015 to 09-2016, 60 breast cancer patients were enrolled; 3 dropped off consent. Mean age was 51 year; 78% had stage II and III; and 65% receive neoadjuvant chemotherapy.There were no significant differences in the VAS pain measurement for the groups of BWT compared to LASW in the 24 hour measurement, neither at rest (P=0.6525) nor in movement (P=0.7929). There were no significant differences in both groups for repeated pain measurements (5 measures mean), total dose of opioid administration, time to first dose of opioids or adverse events.

Conclusions: There were not statistical differences for post-mastectomy acute pain in first 24 hours between TPB and LASW patients. According our findings the use of TPB should not routinely recommended for breast cancer patients undergoing mastectomy.

Citation Format: Herazo-Maya F, Egurrola J, Restrepo CE, Torres L, Palacios L, Ossa CA, Borrero M, Angel GA, Marquez JJ, Valencia S, Perez A, Oyola JC, Lobo L, Gomez R, Garcia H. Efficacy of thoracic paravertebral block for reducing acute post-mastectomy pain [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-22-04.