Prophylactic oophorectomy in premenopausal women with non-metastatic colon cancer: A decision analysis

Abstract

6130 Background: There is data to suggest that prophylactic oophorectomy (PO) in premenopausal women with colon cancer may improve survival. However, the potential for improved survival must be balanced against the trade-off of premature menopause and its affect on quality of life (QOL). The objective of this study was to determine the value of PO in premenopausal women undergoing surgical excision of colon cancer. Methods: We constructed a decision-analytic model comparing PO versus no PO for premenopausal women undergoing resection of stage I-III colon cancer. The model included detection of ovarian micrometastases (OMM), adjuvant chemotherapy, development of metachronous ovarian metastases, subsequent risk of ovarian cancer and QOL. Probabilities and utilities were estimated from published data. Life expectancy (LE) and quality adjusted LE (QALE) were calculated using the Declining Exponential Approximation of Life Expectancy. Results: With a baseline OMM incidence of 8%, a 5 yr survival of OMM removed (19%) vs OMM left in situ (11%), there was a gain in LE of 2.8 months with PO. With QOL adjustments for menopause (utility 0.77) and colon cancer (utility 0.37–0.85 ), QALE was 1.7 months less with PO. One-way sensitivity analysis (SA) demonstrated that the utility of menopause had the greatest effect on QALE differences, with a threshold value of 0.86 at which QALE was greater with PO. With increasing OMM incidence and 5-year survival with removed OMM, QALE became greater in the PO cohort. All 1, 2, and 3 way SAs demonstrated that the model was robust through the probable range of variables. Conclusions: Our model demonstrated the significant effect of menopause QOL on overall QALE. Although PO may lead to a small gain in LE, the trade-off of premature menopause must be considered when counseling patients. No significant financial relationships to disclose.