sábado, 20 de marzo de 2010

Thyroid Remnant Ablation: A Randomized Comparison of Thyrotropin Alfa and Thyroid Hormone Withdrawal.

Thyroid Remnant Ablation: A Randomized Comparison of Thyrotropin Alfa and Thyroid Hormone Withdrawal.
Radioablation of remnant thyroid tissue is often performed after thyroidectomy in patients with epithelial thyroid carcinomas (TC) to eradicate microscopic cancer and improve specificity of monitoring for recurrence. Withholding thyroid hormone therapy postoperatively increases endogenous TSH and stimulates thyroidal 131I uptake, but causes hypothyroidism. We postulated that thyrotropin alfa (rTSH) would be as effective for remnant ablation. Sixty-three patients with TC who had thyroidectomy within 2 weeks were randomized to either 1) hypothyroidism (THW), in which thyroid hormone was withheld until serum TSH was 25 mU/L at 4-6 weeks; or 2) euthyroidism with rTSH, in which thyroid hormone was advanced until TSH was 5 mU/L, after which rTSH was given (Thyrogen®, 0.9 mg qd x 2). Patients then received 100 mCi 131I 24h later. Success of radioablation was evaluated after rTSH at 8±1 mos., based on three criteria: 1) no visible 131I uptake in the thyroid bed; 2) 48h thyroid bed 131I uptake invisible, or if visible, <0.1%; and 3) serum Tg <2 ng/mL 72 hours after rTSH. Mean TSH concentrations in THW and rTSH patients before 131I ablation (and rTSH in that group) were 83±75 and 1.1±1.3 mU/L, respectively.[table1]There were no clinically relevant differences between the ablation rates in THW and rTSH patients. For the two objective criteria, i.e., thyroid bed uptake and serum Tg, ablation occurred in more than 87% of patients in both groups. Based on subjective visible thyroid bed uptake, ablation rates were lower with both techniques. Billewicz hypothyroidism scores were higher at 4 weeks for THW than rTSH patients, 27±7 v. 18±4, respectively (p<0.0001). In conclusion, this multicenter prospective randomized trial found comparable thyroid remnant ablation rates whether TC patients were prepared for postoperative 131I therapy by hypothyroid THW or euthyroid rTSH.
Lasofoxifene, a Next Generation Selective Estrogen Receptor Modulator (SERM), in the Prevention of Bone Loss in Postmenopausal Women
Mark Ettinger*1, Elliott Schwartz2, Ron Emkey3, Alfred H Moffett4, Michael Bolognese5, Stuart R Weiss6, Andrew Lee7. 1Stuart, FL; 2Fdn for Osteoporosis Res and Treatment, Oakland, CA; 3Reading, PA; 4OB-Gyn Assoc of Mid Florida, FL; 5the Bethesda Hlth Res Ctr, Bethesda, MD; 6Radiant Res, San Diego, CA; 7Pfizer Inc, New London, CT.

Lasofoxifene is a potent next generation SERM under development for prevention and treatment of postmenopausal osteoporosis. Results of 1yr, Phase 2, randomized, doubleblind, placebo-controlled study examining efficacy in bone loss prevention and safety of lasofoxifene are reported.
Postmenopausal women (n=190), mean age 50-68 yrs and 6-8 yrs postmenopausal, were randomized to receive lasofoxifene (0.4, 2.5, and 10 mg/d), or conjugated estrogen/medroxyprogesterone (PremPro;0.625/2.5 mg/d), or placebo, plus calcium and vit D daily. Primary end point was % change in BMD of lumbar spine and total hip at 1yr. Secondary analyses included change in markers of bone turnover and lipid metabolism at 1 yr, safety and tolerability.

All lasofoxifene doses increased in lumbar spine BMD statistically significantly compared with pbo (P<0.001); there was no significant difference between groups for hip BMD. All lasofoxifene doses decreased biochemical markers of bone turnover (P<0.01) and LDL-cholesterol (P<0.001) statistically significantly compared with pbo. Similar to spine BMD, this effect was 2/3 of effect with PremPro. Overall safety of lasofoxifene was comparable to pbo. Incidence rates for uterine/ovarian change were low with lasofoxifene. Most commonly reported AEs associated with lasofoxifene were hot flushes, leg cramps, and leukorrhea and with PremPro included breakthrough bleeding and breast pain.
1yr treatment with lasofoxifene prevented lumbar vertebral bone loss in postmenopausal women and was well tolerated.
Maria Gabriela Medina Maldonado
C.I. 16779553

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