Cancer Patients

Question 1

Limitations with Pain Detection in Cancer Patients

Answer 1

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

Question 2

Frequency of Pain In Cancer Patients

Answer 2

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

Question 3

Visual Analog Scale

Answer 3

Horizontal line generally measuring 100mm in length

Vertical mark placed anywhere between 0 (no pain) and 100 (worst possible pain)

Question 4

Numerical Rating Scale

Answer 4

 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

Question 5

Causes of Cancer Pain

Answer 5

1. Direct invasion of tumor cells into nerves, bones, soft tissue, ligaments, fascia
2. Distension, obstruction of internal organs secondary to tumor infiltration
3. Erosive or inflammatory processes elicited by cancel cells within microenvironment

Question 6

WHO Analgesic Ladder - Step 1

Answer 6

Mild to moderate pain
Non opioid +/- adjuvant analgesics

Question 7

WHO Analgesic ladder - Step 2

Answer 7

Moderate to Severe Pain

Weak opioids
+/- non-opioids
+/- adjuvant analgesics

Question 8

WHO Analgesic Ladder - Step 3

Answer 8

Severe Pain

Strong Opioids
+/- Non-opioids
+/- adjuvant analgesics

Question 9

Nociceptive Pain

Answer 9

Direct tissue injury from tumor infiltration,

Peritumoral inflammation –> stimulation of peripheral pain R in cutaneous, deeper MSK structure

Question 10

Somatic pain

Answer 10

Direct injury DT cancer cell invasion into skeleton, soft tissues, tendons, ligaments

In people, described as focal and stabbing in nature

Question 11

Visceral Pain

Answer 11

Arises from cancer cell infiltration, compression, distortion of internal organs within abdominal, thoracic, pelvic cavities

In people, described as diffuse and squeezing in character

Question 12

Neuropathic Pain

Answer 12

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

Question 13

Bone

Answer 13

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

Question 14

Dogs and Bone Tumors

Answer 14

osteosarcoma (OSA) –> focal skeletal pain, can also see with metastatic carcinoma, multiple myeloma

Question 15

Cats and Bone Tumors

Answer 15

primary bone tumors occur less frequently than dogs, bone involvement secondary to invasion by oral SCC

Question 16

Development of Bone Pain

Answer 16

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

Question 17

Main Mechanisms of Bone Cancer Pain

Answer 17

1. Presence of cancer cells –> release of chemical mediators by neoplastic, non-neoplastic stromal cells –> stimulate sensory afferent nociceptors –> painful sensations
2. Generation, maintenance of bone cancer pain directly attributed to pathologic osteoclastic bone resorption
   –Acid-sensing channels
3. Bone erosion, subsequent mechanical instability
    Allows for distortion of punitive mechanotransducers belonging to TRPV R family –> innervate bone

Question 18

How do viable cancer cells directly promote generation of bone pain?

Answer 18

 Secretion of nociceptor activating ligands
 Attraction of trafficking immune cells
 Subversion of osteoclastic activities

Question 19

Osteoclasts

Answer 19

 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

Question 20

How do bone cancers hijack osteoclastic activity?

Answer 20

 Bone cancers of either primary (sarcoma) or metastatic origin (carcin thisoma) dysregulate osteoclastic activities via R activation of nuclear factor kappa-B

Question 21

Aminobisphosphonates

Answer 21

induce osteoclast apoptosis via inhibition of mevalonate pathway
 First line agents for management of malignant skeletal events, bone cancer patients, good for bone pain

Question 22

What form of radiation is the most effective tx for reducing bone pain?

Answer 22

Ionizing radiation