Dapagliflozin and Risk of Cancergerman translation / full article
A 73 year old patient with diabetes mellitus type 2 was prescribed Forxiga® (Dapagliflozin) 10 mg once daily by a diabetologist (although HbA1c was in the upper acceptable range (7.5 %) under a combination of Levemir® (Insulin detemir) 12 IE in the morning and 16 IE at night, Novorapid® (Insulin aspart) between 4 and 20 IE depending on blood glucose level, and Metformin 1000 mg twice daily). The justifying indication for Dapagliflozin was said to be the patient’s desire to loose weight. The BMI of the patient, however, was only 25.6 kg/m².
About six months later (March 2015) the patient was referred to a screening mammography by her gynecologist which revealed a pathologic finding in the upper outer quadrant of her left breast. The biopsy showed a partially solid, partially cribriform ductal carcinoma in situ which was resected in toto. Two months later the patient received adjuvant radiation in the form of brachy-therapy.
The family physician of the patient now wants to know whether the breast cancer could have been caused by the treatment with Dapagliflozin.
In the early approval studies of Dapagliflozin, an increased incidence of breast- and bladder-cancer was seen. This observation was not confirmed in further follow up or in animal studies. A final conclusion regarding this question can only be drawn after a long term safety study which is currently ongoing. The probability of a causal relationship between Dapagliflozin treatment and the development of a DCIS in the patient described above seems low, but it can surely be stated that there was no evidence based indication for the prescription of the drug. Besides “laboratory cosmetics” we have so far no proof of safety or effectiveness regarding patient relevant outcomes for Dapagliflozin.