Acute Postsurgical Pain Management in Patients with Cancer

Introduction

Postoperative pain management is an integral component of the perioperative management of patients requiring surgery. Perioperative management starts early, even before the patient is admitted to the hospital for surgical procedures. The perioperative care team's preoperative optimization of underlying comorbid diseases and associated medications ensures that optimal anesthesia and analgesic strategies are utilized. For example, patients with cardiac disease may have anticoagulants prescribed that need careful discontinuation when neuraxial analgesic modalities, such as epidural catheter placement, are considered. Patients with brain metastases may have compromised neurologic function, which requires careful consideration of centrally acting analgesics. Similarly, patients with hepatic metastases may have impaired metabolic and synthetic liver function and therefore altered drug metabolism and coagulopathy, which may impact the choice of anesthetic and analgesic techniques.

Cancer is one of the leading causes of morbidity and mortality and is associated with a significant burden of pain. The World Health Organization (WHO) executive summary (2018) reported 18.1 million new cases and 9.6 million deaths related to cancer in 2018, with 70% of patients experiencing cancer-related pain while undergoing cancer-related treatment or during the terminal stages of illness. ^, A multidisciplinary approach to pain management in cancer patients is essential and should include pharmacologic, interventional, surgical, and psychologic approaches. Given that surgery remains a cornerstone of cancer care, an acute postoperative pain management strategy is essential. Perioperative pain management in patients with cancer poses distinct challenges that require a systematic, well-thought-out approach starting in the preoperative phase tailored to the individual patient's surgery, underlying comorbid disease, patient's previous experience, and outcomes.

Postoperative Pain Management in Cancer Patients

The perioperative team managing patients undergoing cancer-related surgery may experience specific challenges with regard to postoperative pain management. Some of these challenges include the following.

• Abnormal coagulation profile, particularly in patients with liver dysfunction. Impaired liver function and coagulation factors may be related to primary liver cancer, metastatic liver disease, chemotherapy, immunotherapy, or comorbid disease such as hepatitis C. Thrombocytopenia related to cancer treatment or bone marrow infiltration is another challenge that should be considered when considering neuraxial and regional blocks, for example, epidurals, spinal, plexus blocks, and so on. If a preintervention platelet transfusion is indicated, the risk-benefit profile of the planned intervention should be considered. Consideration should be given to preprocedural laboratory investigations, such as partial thromboplastin time (PTT), prothrombin time/international normalized ratio (PT/INR), and platelet count, to avoid hemorrhagic complications and other specialists (e.g., hematologists) consulted for complex clinical cases.

• Immune compromise, for example, neutropenia, may be seen in patients receiving chemotherapy, mandating regular blood counts to monitor their underlying immune state, and for early signs of infection.

• Preoperative analgesia requirements may be associated with opioid tolerance, a recognized side effect of opioid therapy that leads to dose escalation and higher opioid usage. A typical strategy would be to continue baseline long-acting opioids and add short-acting (prn, as required) opioid medications postoperatively.

• Other preoperative conditions that may affect postoperative analgesia requirements and the effectiveness of interventions include neuropathic pain from radiation therapy, metastatic lesions in the spine or around the neural plexuses, inability to maintain steady posture, cognitive deficits due to cerebral metastasis, impaired drug metabolism, and clearance, such as metastatic liver disease and impaired renal function compromised by renal or pelvic cancers.

Various Analgesic Modalities

Successful postoperative pain management involves the application of multimodal analgesic modalities adapted to the surgical procedure and patient needs. Depending on the modality to be applied, specific precautions must be considered. Opioids are the most commonly used pharmacological agents for acute and chronic cancer-related pain. The WHO guidelines for the pharmacologic management of cancer pain in adults and adolescents are among the most commonly used and validated tools in clinical practice. Despite the availability of several rapid and short-acting opioid and nonopioid agents, a substantial number of patients reportedly have undertreated pain, which adversely affects their mood, activities of daily living (ADLs), and level of satisfaction. Some of the most common modalities for postoperative analgesia include the following.