234. Tamoxifen again

Remember tamoxifen (post #221)?  In some organs (e.g., breasts) it blocks the effect of natural estrogen, in others (e.g. uterus), it acts like an estrogen. 

First chemotherapy for Eve's early-40's breast cancer, followed by a standard 5-year course of tamoxifen, since her cancer was estrogen-sensitive. Periods which had stopped during the chemo resumed for a few years then no periods for several months. A new episode of bleeding prompted her first consult.

Is this postmenopausal bleeding requiring further testing for uterine cancer, or does it reflect non-threatening hormonal variations not unexpected in this setting?

An endometrial biopsy was obtained showing no sign of cancer; then a ultrasound, showing a thin uterine lining (cancer or a pre-malignant condition called hyperplasia) invariably lead to a thick lining. 

7 months later she presents to me with another episode of light bleeding.

We discussed repeating the endometrial biopsy or ultrasound, or scheduling a hysteroscopy, allows direct visualization of the uterine lining while patient is under general anesthesia or sedation (for example, valium and ibuprofen).

Eve seemed inclined to go with the hysteroscopy, then decided to wait and repeat the ultraosound in six months--when she found out she would need a ride home after the hysteroscopy! As good a reason as any, I guess. Any approach has a 2-5% false negative rate with low but not zero health risks.