新青年麻醉论坛

标题: Regional Anesthesia and Breast Cancer Recurrence [打印本页]

---

作者: 曹锡清    时间: 2014-5-10 20:12
标题: Regional Anesthesia and Breast Cancer Recurrence
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.

登录/注册后可看大图