Age-appropriate cancer screening tests should be considered. At your age, I would suggest a PAP smear and mammogram if not done already. Those tests, in addition to the colonoscopy, would screen for cervical, breast and colon cancer respectively, and in most cases would be an appropriate cancer work-up. If you are a smoker, you may want to consider some chest imaging to evaluate for lung cancer - although not every doctor would agree with screening for lung cancer.
If the weight loss continues, there are things like lymphoma (cancer of the lymph nodes) that can cause it - and a CT scan would be reasonble if this is suspected.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
Medical Weblog:
kevinmd_b