Does Higher Starting Dose of FSH Stimulation with Letrozole Improve Fertility Preservation Outcomes in Women with Breast Cancer

Higher FSH start dose does not improve cycle outcomes in women with breast cancer undergoing fertility preservation with letrozole for embryo cryopreservation.

Sanghoon Lee, M.D. and Kutluk Oktay, M.D.

Volume 98, Issue 4, Pages 961-964.e1, October 2012


To evaluate the efficacy of ovarian stimulation with higher doses of gonadotropins in fertility preservation (FP) cycles with the intention to maximize the likelihood of future pregnancies.

Retrospective (secondary analysis).

Academic medical centers.

Low (LD, = 150 IU, n=34) versus high dose (HD, > 150 IU, n=117) FSH start in 151 patients with breast cancer (BCa) undergoing ovarian stimulation for embryo cryopreservation with letrozole (LE) before cancer treatment.


Main outcome measures:
FP cycle outcomes.

Mean total FSH dose (2037±679 IU vs 1128±381 IU, p<0.001) and FSH level on trigger day (21.1±8.9 vs 10.6±4.5 mIU/ml, p<0.001) were higher in the HD group confirming the receipt of higher dose FSH. There was no difference in other patient characteristics. Despite the larger number of follicles >17mm in diameter in the HD group (5.0±2.0 vs 3.4±1.4), neither the peak E2 (498.0±377.5 vs 397.9±320.3), number of oocytes (13.3±8.7 vs 12.3±8.0) nor embryos (6.3±4.7 vs 5.4±3.8) were significantly different from the LD. Of those undergoing frozen embryo transfer (FET), live birth rate/ET (LBR) trended higher in the LD (9/15) compared to HD (2/11) (p=0.051) with 2.1 ±0.8 vs 1.9±0.3 (p=0.496) embryos transferred.

Higher dose FSH stimulation in LE cycles does not improve outcomes and maybe associated with lower LBR. Our findings may support minimal stimulation in young non-infertile women with BCa.

  • Javier Domingo del Pozo

    Congratulations about your issue. We are also using 150 U. + letrozole for ovarian estimulations in breast cancer patients, and our results in terms of retrieved oocytes and MII oocytes are similar to yours. As ours is a relatively young programme, up to the moment we only have warmed the oocytes in four patients, with two clinical pregnancies: one miscarriage and an ongoing pregnancy, and both cases had frozen embryos left, so as you say, this doses may be enough -at least for a reasonable try- and estradiol levels don’t rise so high. Now we are also encouraging to increase doses, moreover depending on the BMI. Which was the daily average dose in the group >150 U? And if you have this information, are results different for the subgroups 200/225 U vs 300 U vs >300 U? Thank you very much!

  • Congratulations for your work. We all agree that in most of cases trending to more physiological and mild stimulations treatments is clearly beneficial for patients. Therefore, in FP patients this is still more important. One question: What do you think about the future for FP, to chose embryo freezing or oocytes? Thank you

  • Kutluk oktay

    We are looking forward to answering any questions or comments. The Authors.

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