The Power of the Placebo in Symptom Management
Mené auprès de 249 patientes atteintes d'un cancer du sein de stade précoce, cet essai randomisé multicentrique analyse l'efficacité d'un traitement à base d'acides gras oméga 3 pour réduire les douleurs musculo-squelettiques induites par les inhibiteurs de l'aromatase
Aromatase inhibitors (AIs) reduce the risk of breast cancer recurrence and death from breast cancer in postmenopausal women in the adjuvant setting.1 However, for many patients, the benefit of adjuvant therapy may not be realized because of the difficulty of managing AI-associated musculoskeletal symptoms (AIMSS)—the primary reason for nonadherence and nonpersistence with this class of medication.2,3 Much research has been, and continues to be, conducted to identify the mechanism underlying development of AIMSS and, even more important, to prevent or effectively manage what has been referred to as treatment-emergent toxicity.4,5 However, despite this investment on the part of investigators and patients alike, minimal definitive progress has been made.
Many researchers have hypothesized that estrogen deprivation leads to development of AIMSS.6,7 However, this hypothesis has been difficult to test, in part because of the imprecision and insensitivity of available estrogen assays at the extremely low circulating estrogen concentrations achieved with AIs.8 Other hypotheses have also been proposed, including that estrogen deprivation leads to systemic inflammation.4,9 This latter hypothesis underlies the design of the trial reported in Journal of Clinical Oncology by Hershman et al.10
The authors10 report the findings of a placebo-controlled randomized trial of omega-3-fatty acids (O3-FAs) versus placebo for 24 weeks in patients with AIMSS.10 They found that patients treated with O3-FA reported a decrease in worst pain of 1.75 on a 10-point scale after 12 weeks of therapy. Although this was a statistically significant improvement with treatment, the improvement was not significantly superior compared with the improvement reported by patients treated with placebo.
Why some patients respond to a therapy that is intended to be inactive, known as the placebo effect, has been extensively studied. The placebo response is related to the expectations and perceptions of the treated patient and can be heightened if there is a supportive patient-provider relationship.11,12 Conversely, the placebo effect can be abolished if a patient is told that the intervention is ineffective. Functional imaging studies have demonstrated increased activity in reward centers and alterations of dopaminergic pathways in the brain in patients treated with placebos, suggesting that they can exert true physiologic responses.13–15 However, in blinded clinical trials, in which patients do not know whether they are receiving the active drug or a matching placebo, the placebo effect is often less apparent. [...]
Journal of Clinical Oncology , éditorial en libre accès, 2015