Abstract

Breast cancer is the most common malignancy in women, impacting on the lives of 2.1 million women each year throughout the world. Despite improvements from earlier detection and more effective treatments, breast cancer remains the main cause of cancer deaths in women. In 2018, it was estimated that 627 000 women died from breast cancer internationally.1 While breast cancer rates are higher in more developed countries, rates are increasing in nearly every region throughout the globe.

Mastectomy is an effective surgical procedure for the treatment of local disease in breast cancer has significant side effects: psychological distress, depression and anxiety, loss of emotional well‐being and self‐esteem, altered body image, and postoperative pain.

Preemptive analgesia is a pain management method used in the perioperative period. Application of analgesic agents in the area of the surgical incision reduces the number of signals generated by pain receptors, preventing central nervous system hypersensitivity resulting in a reduction in disproportionate pain in the perioperative period.

Reducing postoperative pain following breast cancer surgery is an important objective to achieve a more rapid recovery and return to normal life and also results in a shortened hospital stay with economic benefits for healthcare systems.

Surgical wound instillation with a local anesthetic solution is routinely performed in many surgical procedures. Several published randomized controlled trials have investigated the efficacy of intraoperative instillation of two anesthetic agents, bupivacaine or ropivacaine, along the surgical wound of mastectomy. The results, however, were inconclusive.2

Complex techniques, such as thoracic epidural anesthesia and local nerve block including paravertebral and pectoral blocks, have been advocated as postoperative analgesia following mastectomy.3 These techniques are technically challenging and can be associated with complications. Infiltration of local anesthetic along the suture line also provides pain relief but is not recommended due to the risk of needle track seedling and cutaneous spread of malignancy.4 Sidiropoulou et al5 compared the analgesic effect of a single injection of thoracic paravertebral block (PVB) with ropivacaine and continuous irrigation of the wound with ropivacaine through catheters placed subcutaneously after mastectomy. The authors concluded that continuous wound irrigation is as effective as PVB with low pain scores and excellent patient satisfaction.

Talbot et al6 evaluated the effect of local anesthetic irrigation of axillary drains following modified mastectomy but concluded it did not appear to offer any contribution for postoperative analgesia in some of their patients. They opined that this could be because of a malpositioned drain, blockade of some holes of the drain, or unequal distribution of the local anesthetic due to gravity and concluded that further refinement in the technique was needed. Another pilot7 randomized controlled trial compared pain control in 60 patients after modified radical mastectomy, one control group, a group which had wound irrigation with saline and a third group that had irrigation with 0.25% bupivacaine. The mean duration of analgesia in the bupivacaine group was 14.6 hours, 10.3 in the saline group, and 4.3 hours in the control group. These differences were significant. A second RCT8 of 51 patients compared pain control in three groups after mastectomy to with arms: (a) Wound infiltration of LA; (b) Drain administration of LA; and (c) Systemic analgesia only. There was no statistically significant difference in pain scores or duration of drainage between the groups. In this study, systemic analgesia was as effective as local anesthesia after mastectomy.

Further conflicting results have been reported by Khpal9 in a study in which patients with breast cancer were randomly assigned to receive a one‐off dose of levobupivacaine following surgery, either via the surgical drain or by direct skin infiltration. Postoperative pain control at rest and on shoulder abduction was assessed as well as total analgesia consumption. Pain scores were significantly lower when local anesthesia was administered via surgical drain at both 3, 12, and 24 hours postoperatively. No differences were found in the total analgesia consumption or length of hospital stay between treatment groups.

The technique of drug instillation through the surgical drain is technically simple. Operating theater time is also not a constraint because it takes little time to instill the drug through the drains. The technique of anesthetic instillation through drains is well established in surgical procedures like laparoscopic cholecystectomy10 and abdominal hysterectomy11 where the results have shown a positive impact on postoperative analgesia.

Local anesthetic instillation through a surgical drain after mastectomy is an established low‐risk intervention that may provide improved postoperative analgesia and decrease the oral analgesic requirements. We believe this technique has considerable promise and requires rigorous evaluation incorporating a randomized controlled trial design to avoid selection bias and standardization of instillation technique as well as the assessment of agreed endpoints including analgesic usage, standardized pain scores, and complication rates. Certainly, the pilot randomized controlled trials have described above have shown this is a safe technique with some efficacy in studies with small patient numbers. Some lower resource countries may be unable to participate in and deliver studies involving anesthetic options such as complex nerve blocks. Post‐mastectomy wound instillation with local anesthetic is a low‐cost, simple intervention. Given that a proposed study would almost certainly require large numbers of patients to demonstrate efficacy of statistical significance, we would advocate that now is the time for international collaboration and for the development phase of a randomized controlled trial.