Would an ultrasound and a transvaginal ultrasound still miss signs of ovarian cancer?

Unfortunately Yes: Us cannot DX ovarian cancer, simply show signs which may be associated with it. Us may show thickened cyst walls, nodules, septations, or abnormal blood vessels. However, even with tumor markers, ovarian cancer remains a tissue diagnosis & a biopsy/surgery is needed for diagnosis. Even with today's technology, we do not have reliable tests to catch early ovarian cancer. D/w md if you have risks.

Yes: Almost all test and imaging studies have false positive and false negative results. Early ovarian cancer is particularly difficult to detect as the normal ovary often has cystic changes and varies in size during the reproductive period. Having said that, transvaginal ultrasound is a useful and perhaps the best test for detecting ovarian cancer.