Hi there,
Thanks for writing to us,
Endometrial thickening itself is not a cancerous condition .There are various reasons for prolonged bleeding like
endometriosis, fibroids etc , . Advisable to probe into the cause of
cyst .she has been prescribed with dupaston ( an dydrosterone
hormonal tablet )to look out for the symptoms.
Do not worry much, wait until the results, get an proper diagnosis and treated accordingly.
Let me know if you have future questions,
Take care of your sister.