Salivary Estrogens Androgens and Aromatase Inhibitors by LC-MS/MS in Breast Cancer Patients Treated With Testosterone Pellets Combined With Aromatase Inhibitors

Introduction: High dose testosterone (T) has been used for treating hormone-sensitive breast cancers for many years. However, a drawback to T therapy is its propensity to convert to estradiol (E2) via aromatase, which can override the growth inhibitory effects of T and stimulate estrogen sensitive tumors. Aromatase is higher in some women than others, particularly those with active tumors, truncal obesity, and inflammatory conditions contributing to and caused by cancer. Oral aromatase inhibitors (AI) have been used to prevent conversion of T to E2. While this effectively reduces E2 burden, systemic oral AI require higher dosing, which often leads to severe side effects. As an alternative to oral AI therapy, researchers have found that T combined with a much lower dose of AI in a solitary pellet implant placed in the subcutaneous (SC) tissue, or alternatively, into the breast adjacent to a primary tumor, is effective in reducing tumor burden and maintaining a low systemic level of E2, while reducing the adverse side effects of very low E2. Study Design: In this case study we report on the use of an LC-MS/MS method to monitor salivary levels of E2, Estrone (E1), T, and the AIs Letrozole (LET) and Anastrozole (ANZ) following T + AI therapy in a breast cancer patient (intolerant of oral LET) with active (measurable) tumor in the breast and metastatic disease. Steroids and AIs were measured in saliva at baseline, 1 week, and 4 weeks after insertion of subcutaneous pellets containing ‘60 mg T + 4 mg ANZ’ and ‘60 mg T + 6 mg LET’. Results: LC-MS/MS (range values-pg/ml) for postmenopausal women, and baseline, week 1 and week 4 post treatment values for each steroid and AI were: E2: (range 0.3-0.9), 0.4, < 0.3, < 0.3; E1: (range 0.9-3.1), 1.0, <0.4, <0.4; T: (range 7-22), 6, 96, 48; ANZ: (range <4), < 4, 2063, 24; LET: (range <4), < 4, 744, 175. Self-reported (Pre/Post Therapy) estrogen deficiency symptoms such as hot flashes, night sweats, vaginal dryness, joint pain, and sleep disturbances were significantly improved post T+AI therapy. In addition, the intramammary tumor decreased in size > 95% by month 5. Summary: These results show that low-dose SC AI therapy (4-6 mg/2-3 months = 0.1 mg/day) with T (120 mg/2-3 months = 1-2 mg/day) increases T to supra-physiological levels, prevents T metabolism to estrogens E2 and E1, reduces estrogen deficiency symptoms, and has beneficial effects on tumor growth inhibition. Simultaneous testing of sex-steroids E2, E1, T, and aromatase inhibitors LET and ANZ by LC-MS/MS provides a convenient means to monitor the bioavailable levels of these analytes and adjust them as necessary to optimize therapeutic efficacy and reduce adverse side effects.