1. Fatigue in the Advanced Cancer Patient
Doctor, why am I so tired?

2. Fatigue & Cancer Definitions Causes Pathophysiology Assessment
Treatment issues

3. Fatigue & Asthenia Greek (Asthenos) “absence or loss of strength”
Combination of physical & mental fatigue
May precede diagnosis
Often ass’d with cachexia
Worsened by chemo/RT/surg
Rarely assessed or treated

4. Symptom Prevalence Pain Fatigue/Asthenia Constipation Dyspnea Nausea
Delirium
Depression/suffering % %
70%
60% % % %

5. Asthenia 3 elements Fatigue
easily tired;  ability to maintain adequate performance
Weakness
subjective sensation; difficulty initiating activity (not neuro/muscular disease)
Mental fatigue
impaired concentration, memory loss & emotional lability

6. Etiology Cachexia/malnutrition Dehydration Infection
Hematologic causes
Metabolic disorders
Chronic hypoxia
Neurologic dysf’n
Psychogenic causes
Endocrine disorders
Insomnia
Chronic overexertion
Pharmacologic
Cardio/pulm disorders
Liver failure
Renal failure
Chemo/RT

7. Causes Electrolyte disorders  Ca++,  K+,  Mg++,  Na+
Endocrine disorders
 thyroid,  cortisol, diabetes
Hematologic
 Hgb,  WBC

8. Causes Infections TB, viral (e.g. hepatitis), fungal
Neurologic disorders
auto dysf’n, myasthenia, parkinsonism
Pharmacologic
chemotx, sedatives, EtOH, narcotics

9. Mechanisms 3 factors Direct: produced by tumor
Induced: secondary to tumor effect
Accompanying: associated with malignancy, contribute to asthenia

10. CNS Mechanisms Hypothetical, little actual research
RAS active in fatigue experience
cortical stimulation & sensory activity
Chronic stimulation (pain) may yield fatigue
Physical fatigue may protect RAS
Asthenia d/t breakdown of RAS by stimuli from
environment & cortex; humoral factors

11. Mechanisms in Muscle Cachexia = loss of muscle and fat
Pts with N caloric intake may show:
 lactate production
atrophy of type II fibres
 cathepsin-D
impaired mm function
Caused by ‘asthenins’/cytokines

12. Assessment Why? Subjective sensation; self-assess best
Characterize, monitor, research purposes
Many tools developed
Gold standard (nonexistent):
simple, easily understood
valid, reliable, multidimensional

13. Assessment Tools Unidimensional Performance status (Karnofsky, ECOG)
Rhoten Fatigue Scale
Multidimensional
F’nal Assessment of Cancer Tx (FACT)
Edm F’nal Assessment Tool (EFAT)
Multid’nal Fatigue Inventory (MFI-20)

14. Management Pharmacologic measures Corticosteroids (Decadron)
 appetite, energy, short-term
Amphetamines (Ritalin)
 sedation,  activity, opioid ass’n
Megesterol acetate (Megace)
 appetite, ? asthenia, expensive

15. Management Promising Rx treatments Thalidomide
 AIDS wasting, anti-TNF
Melatonin
Cannabinoids
Clenbuterol
-3 fatty acids

16. Management Non-pharmacologic measures Moderate exercise Adapting ADL
Rest, energy conservation
Psychotherapy
Self-help; activity diary
Family/caregiver involvement

17. Conclusions Common condition Multiple causes Mechanisms unclear
Assessment important
Multidimensional treatment
More research needed