Cancer Patients Flashcards
Limitations with Pain Detection in Cancer Patients
Majority of conventional pain scales validated in context of acute, postoperative pain or chronic OA pain
o Suitability for cancer pain assessment might be limited
Frequency of Pain In Cancer Patients
Pain = common aliment inhuman cancer patients, incidence of cancer related pain at initial dx ~ 30%
o Upon disease progression up to 60 to 85% human cancer patients experience pain
Visual Analog Scale
Horizontal line generally measuring 100mm in length
Vertical mark placed anywhere between 0 (no pain) and 100 (worst possible pain)
Numerical Rating Scale
Evaluator chooses a number often btw 0-5
Other numbers both higher and lower used
0 represents no pain, highest number on scale = worst pain imaginable
Causes of Cancer Pain
- Direct invasion of tumor cells into nerves, bones, soft tissue, ligaments, fascia
- Distension, obstruction of internal organs secondary to tumor infiltration
- Erosive or inflammatory processes elicited by cancel cells within microenvironment
WHO Analgesic Ladder - Step 1
Mild to moderate pain
Non opioid +/- adjuvant analgesics
WHO Analgesic ladder - Step 2
Moderate to Severe Pain
Weak opioids
+/- non-opioids
+/- adjuvant analgesics
WHO Analgesic Ladder - Step 3
Severe Pain
Strong Opioids
+/- Non-opioids
+/- adjuvant analgesics
Nociceptive Pain
Direct tissue injury from tumor infiltration,
Peritumoral inflammation –> stimulation of peripheral pain R in cutaneous, deeper MSK structure
Somatic pain
Direct injury DT cancer cell invasion into skeleton, soft tissues, tendons, ligaments
In people, described as focal and stabbing in nature
Visceral Pain
Arises from cancer cell infiltration, compression, distortion of internal organs within abdominal, thoracic, pelvic cavities
In people, described as diffuse and squeezing in character
Neuropathic Pain
Directly related to cancer cell infiltration of peripheral N, nerve plexi, roots, SC
In people, described as burning, shooting, pins/needles, or numbness in nature
Bone
living organ, rich in blood supply, nerves
Fxn: bearing weight, withstanding cyclic compressive forces
Compromise in structural integrity (quantity, quality) = risk for pain, pathologic fx
Dogs and Bone Tumors
osteosarcoma (OSA) –> focal skeletal pain, can also see with metastatic carcinoma, multiple myeloma
Cats and Bone Tumors
primary bone tumors occur less frequently than dogs, bone involvement secondary to invasion by oral SCC
Development of Bone Pain
Skeletal bone: mosaic of afferent nociceptors, most closely concentrated within periosteum, intramedullary cavity
To a lesser extent within mineralized bone matrix
Progressive intramedullary tumor cell growth + consequent chronic afferent nociceptor stimulation neurochemical characteristics of chronic bone pain detected in both peripheral, central compartments
–Peripheral = afferent nociceptors, DRG
–Central: DH of SC
Main Mechanisms of Bone Cancer Pain
- Presence of cancer cells –> release of chemical mediators by neoplastic, non-neoplastic stromal cells –> stimulate sensory afferent nociceptors –> painful sensations
- Generation, maintenance of bone cancer pain directly attributed to pathologic osteoclastic bone resorption
–Acid-sensing channels - Bone erosion, subsequent mechanical instability
Allows for distortion of punitive mechanotransducers belonging to TRPV R family –> innervate bone
How do viable cancer cells directly promote generation of bone pain?
Secretion of nociceptor activating ligands
Attraction of trafficking immune cells
Subversion of osteoclastic activities
Osteoclasts
Monocyte-macrophage cell lineage
Characterized by high expressions of tartrate-resistant acid phosphatase, cathepsin K
Homeostatic conditions: resorb bone in balance with new bone formation by osteoblasts
How do bone cancers hijack osteoclastic activity?
Bone cancers of either primary (sarcoma) or metastatic origin (carcin thisoma) dysregulate osteoclastic activities via R activation of nuclear factor kappa-B
Aminobisphosphonates
induce osteoclast apoptosis via inhibition of mevalonate pathway
First line agents for management of malignant skeletal events, bone cancer patients, good for bone pain
What form of radiation is the most effective tx for reducing bone pain?
Ionizing radiation
