It was a Bill Roberts article with what I thought were reputable references so I blindly accepted this as a fact.
Upon doing my own research I am not so certain this is the case. I recede that statement until I can confirm that it is or is not true.
J Steroid Biochem Mol Biol. 2002 Apr;80(4-5):411-8.
Short-term effects of anastrozole treatment on insulin-like growth factor system in postmenopausal advanced breast cancer patients. Short-term effects of anastrozole... [J Steroid Biochem Mol Biol. 2002] - PubMed - NCBI
Ferrari L1, Martinetti A, Zilembo N, Pozzi P, Buzzoni R, La Torre I, Gattinoni L, Catena L, Vitali M, Celio L, Seregni E, Bombardieri E, Bajetta E.
Abstract
Insulin-like growth factors (IGFs) play a fundamental role in cancer development by acting in both an endocrinal and paracrinal manner, and hormone breast cancer treatments affect the IGF system by modifying circulating growth factor levels. We evaluated total IGF-1, IGF-2, IGF binding protein (IGFBP)-1 and IGFBP-3 in the blood of 34 postmenopausal advanced breast cancer patients (median age 63 years, range 41-85) treated with anastrozole, a non-steroidal structure aromatase inhibitor (NSS-AI). The plasma samples were obtained at baseline, and after 2, 4, 8 and 12 weeks of treatment. The IGFs were quantitated by means of sensitive radioimmunoassays (RIAs).
IGF-1 significantly increased during anastrozole treatment (baseline versus 12 weeks, P=0.031), IGF-2 showed a trend towards an increase, and IGFBP-1 constantly but not significantly decreased; IGFBP-3 did not seem to be affected at all. The anastrozole-induced changes in IGFs and IGFBP-1 appeared to be different in the patients receiving a clinical benefit from those observed in non-responders.
We have previously shown that letrozole (a different type of NSS-AI) modifies blood IGF-1 levels, and the results of this study of the biological effects of anastrozole on the components of the IGF system confirm our previous observations.
J Cancer Res Clin Oncol. 2013 May;139(5):837-43.
Insulin-like growth factor 1 and musculoskeletal pain among breast cancer patients on aromatase inhibitor therapy and women without a history of cancer. Insulin-like growth factor 1 and mus... [J Cancer Res Clin Oncol. 2013] - PubMed - NCBI
Gallicchio L1, MacDonald R, Helzlsouer KJ.
Abstract
PURPOSE: Musculoskeletal pain is a common side effect of aromatase inhibitors (AIs), the adjuvant hormonal treatment of choice for postmenopausal estrogen-receptor-positive breast cancer. Although the pain is usually attributed to the estrogen depletion associated with AIs, not all women on AIs experience these symptoms. Thus, the goal of this study was to examine whether changes in the insulin-like growth factor (IGF) axis were associated with pain among women initiating AI therapy or a comparison group of women without a history of cancer.
METHODS: Data were analyzed from a cohort study of 52 breast cancer patients for whom AI therapy was planned and 88 women without a history of cancer. Questionnaire data on pain symptoms were collected, and blood was drawn at baseline (prior to AI therapy for patients) and 6 months after baseline. The blood samples were assayed for IGF-1 and IGF-binding protein-3 (IGFBP-3).
RESULTS: While results showed no statistically significant changes in any of the measures across time for either the breast cancer or the comparison group,
increases in both IGF-1 concentrations and the IGF-1/IGFBP-3 ratio over the first 6 months of AI treatment were significantly associated with the onset or increase in musculoskeletal pain among the breast cancer patients. Associations between IGF-1, IGFBP-3, and the IGF-1/IGFBP-3 ratio and pain were not observed in the comparison group.
CONCLUSIONS: Although preliminary, findings from this study implicate the IGF axis in the development of AI-associated musculoskeletal pain and represent a first step in developing effective interventions to alleviate this side effect.