| Regional Anesthesia and Breast Cancer Recurrence Cathy X. Cao(曹锡清), MD Medstar Washington Hospital Center Washingon DC, USA May 10, 2014 Within the US alone, more than 3 million women are living with a history of breast cancer, about one in eight women will develop invasive breast cancer over the course of their lifetime. According to the National Center for Health Statistic, approximately 78,000 women get mastectomies each year. The number of new cases of invasive breast cancer in 2013 is estimated to be 232,000. As anesthesiologists, we often confront challenges like what can we do perioperatively to affect our patients’ long term outcome? Can we make a difference by choosing a technique to improve their quality of life, alleviate postop pain and nausea/vomiting, minimize their cardiovascular and pulmonary complications, and even help reduce the risk of cancer recurrence or metastasis? Recent research of regional anesthesia on breast cancer has shown consistent preliminary data that paravertebral analgesia for breast cancer surgery reduced risk of recurrence or metastasis approximately four-fold during 2.5 to 4 year follow-up period compared to opioid analgesia. The investigators will thus test the hypothesis that recurrence after breast cancer surgery is lower with regional anesthesia/analgesia than with general anesthesia and opioid analgesia. Currently, there is multi-center phase III clinical trial sponsored by NCI grant involving age 18-85 years old stage 1-3 women having mastectomies or isolated lumpectomies with axillary node dissection. Patients will be randomly assigned to thoracic epidural or paravertebral anesthesia/analgesia, or to general anesthesia with morphine analgesia. Participants will be followed for up to 10 years to determine the rate of cancer recurrence or metastasis. Background Information Surgery is the primary and most effective treatment of breast cancer, but residual disease in the form of scattered micrometastases and tumor cells are usually unavoidable. Whether minimal residual disease results in clinical metastases is a function of host defense and tumor survival and growth. At least three perioperative factors shift the balance toward progression of minimal residual disease: 1. Surgery per se depresses cell-mediated immunity, reduces concentrations of tumor-related anti-angiogenic factors (e.g., angiostatin and endostatin), increases concentrations of pro-angiogenic factors such as VEGF, and releases growth factors that promote local and distant growth of malignant tissue. 2. Anesthesia impairs numerous immune functions, including those of neutrophils, macrophages, dendritic cells, T-cell, and natural killer cells. 3. Opioid analgesics inhibit both cellular and humoral immune function in humans, increase angiogenesis, and promote breast tumor growth in rodents. However, regional analgesia attenuates or prevents each of these adverse effects by largely preventing the neuroendocrine surgical stress response, eliminating or reducing the need for general anesthesia, and minimizing opioid requirement. Techniques of Thoracic Paravertebral Block(TPVB) A number of approaches and techniques have been described for performing ultrasound-guided thoracic paravertebral blocks. The ultrasound probe may be placed in a transverse position, a paramedian longitudinal position, or in an oblique plain. The needle may then be inserted in an in-plane or out-of-plane fashion. In addition, a catheter may be inserted using any of these approaches. A 5-12 MHz linear array probe is most commonly used, but a curved array ultrasound probe may be used as well. These blocks may be placed in the prone, lateral decubitus or seated position. Hence, the list of possible techniques available to place a thoracic paravertebral block is quite extensive. At the current time, no single technique has been shown to be more effective, easier to perform, or safer for the patient. A single injection will cover 4-5 dermatomes and is adequate for many procedures such as a mastectomy or pain management for rib fractures. Some practitioners prefer to perform a thoracic paravertebral block at two or three levels. The most commonly used agents are Bupivicaine 0.5% and Ropivicaine 0.5% with epinephrine 1:200,000-1:400,000.  Figure 1. Anatomy of Thoracic Paravertebral Space The paramedian sagittal thoracic nerve block may be performed in plane and out of plane. An out of plane block may be placed in a parellel fashion with the probe in a longitudinal paramedian position or with the probe in a transverse position. An in plane paramedian sagittal block is placed with the probe in a vertical position approximately 2.5-3 cm lateral to the midline between two transverse processes. Both transverse processes should be visualized, with the superior costotransverse ligament and the pleura visible in between (figure 2). A 20 gauge blunt tipped block needle or a 22G Tuohy needle is introduced in a cephalad direction. The tip of the needle is advanced under direct visualization until it pierces the superior costotransverse ligament. If the superior coststransverse ligament is not easily seen, the needle is advanced until it is directly above the pleura. Due to the steep angle with which the block needle enters the tissue, the needle is often difficult to visualize. For this reason some practitioners choose to inject small aliquots of normal saline intermittently as they advance the needle to confirm the position of the tip. When the needle tip is located immediately above the pleura, the needle is aspirated to confirm the absence of blood or air. After this, 10-20 cc of local anesthetic is injected in 3-4 cc increments. Spread of local anesthetic with depression of the pleura will be clearly visualized. The extent of local anesthetic spread should be evaluated by moving the ultrasound probe superiorly and inferiorly. When performing an out of plane paramedian sagital block the probe may be placed as described above. In this case the needle is placed at the side of the probe and is advanced with small aliquots of normal saline injected to evaluate the position of the tip by "tissue dissection". When the superior costotransverse ligament is pierced and after careful aspiration, the pleura will be depressed by the injection of normal saline. This is followed by injection of 10-20 cc local anesthetic injected in 3-4cc increments. When a catheter is placed using this technique it is generally threaded approximately 3 cm beyond the tip of the needle( Figure 3). The historical incidence of pneumothorax with TPVB is 0.3-0.5%, so patients receive a chest radiograph postoperatively to rule out pneumothorax before being discharged home.  Figure 2: Longitudinal, out-of-plane approach to thoracic paravertebral block. The transducer is first placed 5-6 cm lateral to the spinous processes to identify ribs, parietal pleura and intercostal spaces (A1-A3). The transducer is then moved progressively medially to identify transverse processes (B1-B3). Transverse processes (TP) appear square and deeper then ribs (round, superficial). The needle is inserted out-of-plane to contact the TP (C1-C2 and C3, line 1) and then walked off the TP (C3, line 2) inferior or superior to TP to enter the paravertebral space and injection local anesthetic (blue). Proper injection displaces the pleura (blue arrows). PVM - paravertebral muscles.  Figure 3. Continuous thoracic paravertebral block. The catheter is inserted 3 cm past the needle tip. Mastectomy as an Outpatient Procedure Pathway Mayo clinic has developed a program featuring multimodal pain control, including PVB, celebrex and gabapentin, which enable patients to be discharged home the same day of their operation. At the preop clinic, patients need to learn to change bandages, care for the incision, understand the surgical drain and be familiar with issues that may indicate the need for a doctor’s evaluation. Furthermore, before the implementation of the program, the multidisciplinary breast staff was educated as to the protocol and reassured the requirements of the patient could be met postoperatively prior to discharge home. Not only is TPVB associated with low pain scores, low PONV and high patient satisfaction, it has also proven to be cost-effective. Boughey et al. found that the use of TPVB decreased the overnight admission rate from 97% to 61% after major breast surgery. The benefits of TPVB continue beyond the length of local anesthetic. By blocking the nociceptic inputs, patients at their one-month, six-month and one-year follow up evaluations had significant less pain than their non-block counterparts, indicating a role in preventing chronic postmastectomy pain syndrome. Reference: 1. www.cancer.gov/clinicaltrials/se ... =HealthProfessional 2. www.nysora.com 3.www2.kenes.com/asraspring2012/sci/Documents/Fleischmann_PS03_Thoracic%20Paravertebral%20Blocks.pdf 4. Exadaktylos AK et al. Can Anesthetic Technique for Primary Breast Cancer Surgery Affect Recurrence or Metastasis? Anesthesiology 2006; 105:660-664 5. Boughey JC et al. Improved postoperative pain control using thoracic paravertebral block for breast operations. The Breast Journal 2009; 15:483-488 6. Kairalumoa PH et al. Preincisional paravertebral block reduces the prevalence of chronic pain after breast surgery. Anesthesia and Analgesia 2006; 103:703-708b  Figure 1-2-3.docx |
This article demonstrated that anesthesia selection can affect long term outcome. It also proved tha ...
黄建宏 发表于 2014-5-11 07:51
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