Chow, H.‐H. Sherry

Abstract Aromatase inhibitors (AI) profoundly suppress estrogen levels in postmenopausal women and are effective in breast cancer prevention among high-risk postmenopausal women. Unfortunately, AI treatment is associated with undesirable side effects that limit patient acceptance for primary prevention of breast cancer. A double-blind, randomized trial was conducted to determine whether low and intermittent doses of letrozole can achieve effective estrogen suppression with a more favorable side-effect profile. Overall, 112 postmenopausal women at increased risk for breast cancer were randomized to receive letrozole at 2.5 mg once daily (QD, standard dose arm), 2.5 mg every Monday, Wednesday, and Friday (Q-MWF), 1.0 mg Q-MWF, or 0.25 mg Q-MWF for 24 weeks. Primary endpoint was suppression in serum estradiol levels at the end of letrozole intervention. Secondary endpoints included changes in serum estrone, testosterone, C-telopeptide (marker of bone resorption), lipid profile, and quality-of-life measures (QoL) following treatment. Significant estrogen suppression was observed in all dose arms with an average of 75% to 78% and 86% to 93% reduction in serum estradiol and estrone levels, respectively. There were no differences among dose arms with respect to changes in C-telopeptide levels, lipid profile, adverse events (AE), or QoL measures. We conclude that low and intermittent doses of letrozole are not inferior to standard dose in estrogen suppression and resulted in a similar side-effect profile compared with standard dose. Further studies are needed to determine the feasibility of selecting an effective AI dosing schedule with better tolerability. Cancer Prev Res; 9(2); 142–8. ©2015 AACR.

Abstract COX inhibitors reduce colorectal adenoma recurrence by up to 45% and selenium supplementation may prevent colorectal cancer. Following colonoscopic adenoma resection, 1,600 men and women, ages 40 to 80 years, were randomized to celecoxib (400 mg daily), a selective COX-2 inhibitor, and/or selenium (200 μg daily as selenized yeast), or double placebo. The trial was initiated in November 2001. The primary trial endpoint is adenoma recurrence in each intervention group compared with placebo, as determined by surveillance colonoscopy conducted three to five years after baseline. Randomization was stratified by use of low-dose aspirin (81 mg) and clinic site. Following reports of cardiovascular toxicity associated with COX-2 inhibitors, the celecoxib arm was discontinued in December 2004 when 824 participants had been randomized. Accrual continued with randomization to selenium alone or placebo. Randomization of the originally planned cohort (n = 1,621) was completed in November 2008. A further 200 patients with one or more advanced adenomas (denoting increased risk for colorectal cancer) were accrued to enhance statistical power for determining intervention efficacy in this higher-risk subgroup. Accrual of the total cohort (n = 1,824) was completed in January 2011. Baseline cohort characteristics include: mean age 62.9 years; 65% male; body mass index (BMI) 29.1 ± 5.1; 47% taking low-dose aspirin while on trial; 20% with three or more adenomas; and 38% with advanced adenomas. Intervention effects on adenoma recurrence will be determined, and their modification by genetic background and baseline selenium level. The effect of selenium supplementation on risk for type II diabetes will also be reported. Cancer Prev Res; 5(12); 1381–93. ©2012 AACR.