Extending aromatase inhibitor adjuvant therapy to 10 years.
www.thelancet.com/oncology Vol 17 July 2016 e275 Postmenopausal women with hormone receptor positive early breast cancer could benefit by extending adjuvant therapy with aromatase inhibitors from 5 years to 10 years, a new double blind, phase 3, placebo controlled trial study suggests. Paul Goss (Massachusetts General Hospital Cancer Centre, MA, USA) and colleagues' study enrolled postmenopausal women with primary breast cancer who had received 4*5 6*0 years of adjuvant therapy with an aromatase inhibitor, most of whom had previously been treated with tamoxifen and who were disease free at the time of enrolment. 1918 patients were randomly assigned to receive 25 mg letrozole or placebo daily for a further 5 years. At a median follow up of 6*3 years, 67 (7% of 959 patients in the letrozole group had disease recurrence or contralaleral breast cancer compared with 98 (10% of 959 patients in the placebo group. 5 year disease free survival (the primary endpoint) was 95% (95% CI 93 96) in the letrozole group and 91% (89 93) in the placebo group, (0*66 hazard ratio [95% CI 0*48 0*91] p=0*01) 5 year overall survival was similar between groups: 93% (95% CI 92 95) with letrozole and 94% (92 95) with placebo (HR 0*97, 95% CI 0*73 1*28; p=0*83) Except for bone related toxic eff ects, which occurred more frequently in the letrozole group compared with the placebo group, the toxic eff ects were similar. Commenting on the study, Miguel Martin (Hospital General Universitario Gregorio Maranon, Madrid, Spain) said that "this [study] is very relevant clinically, is practicechanging, and should be discussed with our patients as a new option, taking into consideration the pros (reduction of contralateral breast cancers and local regional and distant metastases) and the cons (lack of survival benefi t and negative bone eff ects of letrozole) of the therapy." He continued, "Avoiding a contralateral breast cancer, regardless of the lack of benefit on survival, is a goal by itself." Goss told The Lancet Oncology, "We are conducting deeper analyses to determine which patients should or should not continue [alignment therapy] We have reduced recurrences or occurrences by 34% which is clinically very significant." However, he concluded, "Extending a therapy clinically for 5 years is important and my opinion is that..a sober judgment by properly appointed guideline committees is needed" before such changes are instituted.
The Lancet. Oncology