38f. lost 66lbs since march due to change of diet and exercise. i am low on estrogen. i had a ct of pelvic w/contrast would that of detected cancer?

Possibly: But not necessarily. Mass lesions suspicious of malignancy may be detectable by ct scanning, but proof of the nature of the suspicious area must be by biopsy and pathology. The best approach here would be to follow up with your gynecologist and have a determination as to the reason for low estrogen and to perhaps disprove your suspicion of cancer.

Possibly: What cancer are you worried about? It will usually detect cancer of pelvis/ovaries. Why did you doctor order ct? What was he/she concerned about? Contrats on losing that much weight, by the way!