American Society of Regional Anesthesia and Pain Medicine August 2018 - 19

Cancer Pain: A Review of Interventional Treatment and Argument
for Early Involvement by Pain Physicians

P

atients with cancer are often more afraid of pain associated
with their disease than anything else. Pain can be from
the cancer itself but also from the medical and surgical
treatments. Since the WHO ladder was introduced in 1986, opioids
have become a centerpiece in the management of cancer pain
and have done a good job managing pain in a large percentage of
patients.1 However, 10-15% of patients do not have adequate pain
control, despite maximal medical therapy. An estimated 15 million
new cases of cancer per year will be diagnosed by 2020, and we
need to find a better way to manage pain for those patients.2

Further, concerns are growing over problems with opioids,
including tolerance, opioid-induced hyperalgesia, endocrinopathies,
decreased libido, mood changes, and cognitive dysfunction
associated with opioid use.3-5 Common side effects such as nausea,
constipation, sedation, and dizziness can further limit patients'
quality of life. Finally, a developing body of research is showing
potential angiogenesis and tumor metastases with opioid use,
likely related to the immunosuppressive, proinflammatory, and
proangiogenic effects of opioids.6 Opioids cannot be avoided in
cancer, but they need to be part of a multimodal approach to pain.
The following is a review of interventional options available as part
of that multimodal approach, and an argument for performing these
interventions earlier in the
disease course.

Justin Merkow, MD
Resident, Anesthesiology

Narayana Varhabhatla, MD
Assistant Professor, Pain and
Anesthesiology

University of Colorado Hospital
Aurora, Colorado

consumption in the first 12 months (p < 0.001), and improved
quality of life (p < 0.05).9 Other studies have also shown that early
treatment is associated with improved pain, decreased escalation
of opioids, and delayed development of pain.8,10
Superior hypogastric
plexus blocks (SHPB) are
done for visceral pelvic
pain from cancers of the
uterus, cervix, ovaries,
prostate, bladder, and
rectum. Pain from these
cancers is notoriously
difficult to treat, because the innervation of the viscera is very
heterogeneous and difficult to control with one block or one class of
medications. However, Mishra and colleagues11 compared patients
with advanced gynecologic malignancy and severe pain with
medical management and combined medical management with
superior hypogastric plexus neurolysis. The block group reported
significantly decreased pain scores at 1 week, 1 month, 2 months,
and 3 months (p < 0.05). The use of rescue morphine consumption
was less at 1 week and 1 month (p < 0.05) and global satisfaction
score were improved at 1 week and 1 month in the SHPB group (p
< 0.001 and p = 0.04, respectively).11

"Opioids cannot be avoided in cancer,
but they need to be part of a multimodal
approach to pain."

Celiac plexus blocks (CPB)
are done for upper abdominal
visceral pain, most
commonly from pancreatic
cancer. Pancreatic cancer
often causes intractable pain not amenable to pharmacological
treatment.7 This block was one of the first sympathetic blocks
performed by pain management specialists, and recent evidence
shows that earlier celiac blocks improve outcomes in pancreatic
cancer. In a meta-analysis of seven randomized, controlled trials,
Zhong and colleagues compared medical management to combined
medical management with neurolytic CPB. CPB was associated with
significantly lower pain scores at 4 weeks. In all studies except for
one, pain scores were lower at 2, 4, and 8 weeks. The combined
group also had significantly lower drug use and incidence of
nausea and vomiting. Interestingly, the meta-analysis found that
the timing of the block may influence outcomes and patients
undergoing the block prior to the development of severe pain had
less long-term pain and delayed onset.8
Developing evidence indicates that blocks done earlier in the WHO
ladder are beneficial. Amr and Makharita9 performed a multicenter,
randomized, control trial of 109 patients receiving sympathetic
blocks for abdominal and pelvic cancer before step 2 of the
WHO ladder versus after step 3. The early treatment group had a
greater number of block responders (p < 0.001), decreased opioid

Ganglion of Impar (GI) blocks are done for perineal pain from cancer
of the rectum, vulva, and anus, as well as metastases from other
sites. It is a plexus that innervates the perineum, distal rectum,
anus, distal urethra, vulva, and distal vagina. Although reports in
the literature are limited mostly to case reports and case series, GI
blocks consistently show improved outcomes with minimal risk of
adverse effects.12,13 Interestingly, in one study by Ahmed et al14-a
combined neurolytic GI with SHPB in 15 patients with pelvic or
perineal pain-the pain scores were significantly decreased (7.87

American Society of Regional Anesthesia and Pain Medicine
2018

19



Table of Contents for the Digital Edition of American Society of Regional Anesthesia and Pain Medicine August 2018

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