Purpose: To evaluate decision quality in patients deciding between lumpectomy and mastectomy, by measuring decision-specific knowledge, concordance between goals and treatment, and involvement in decision making.
Method: A cross-sectional survey was conducted in early stage breast cancer patients 1 to 3 months after surgery at four sites. The survey covered facts about surgical options, goals and concerns related to surgery, and interaction with providers. A knowledge score (0 to 100%) was calculated, and characteristics associated with knowledge were identified using multivariable linear regression. A multivariable logistic regression model of treatment was developed, including clinical variables and patients’ goals/concerns. The model-predicted probability of mastectomy was computed for each patient. Patients with a predicted probability >=0.5 who had mastectomy and those with a predicted probability <0.5 who had lumpectomy were classified as having care concordant with their goals. A concordance score (0 to 100%) was calculated as the proportion of patients who received concordant care.
Result: 266 patients completed surveys (response rate 60%). The mean overall knowledge score was 71.3% (SD 15.7). Most (78.6%) knew that breast conservation and mastectomy have equivalent survival. A minority (37.6%) knew that risk of recurrence is higher with breast conservation. College education (beta=7.95, p=0.0004), white race (beta=7.30, p=0.04), and having lumpectomy (beta=6.77, p=0.008) were associated with higher knowledge. The desires to “remove your breast for peace of mind” (OR 2.08, 95% CI 1.66, 2.59), “avoid radiation” (OR 1.22, 95% CI 1.03, 1.43), and “keep your breast” (OR 0.80 CI 0.68, 0.94) were associated with treatment. Most patients (90.9%) had treatment that was concordant with their goals, but women whose goals predicted lumpectomy were more likely to have concordance (93.7%) than women whose goals predicted mastectomy (82.8%, p=0.02). According to patient report, providers discussed lumpectomy more frequently than mastectomy (91.4 vs. 74.8% of patients) and mentioned the advantages of lumpectomy more often than the advantages of mastectomy (86.1% vs. 50.4% of patients).
Conclusion: Breast cancer patients had fairly good knowledge about surgery. Patients with lower education had more knowledge deficits. Most patients had treatment concordant with goals, but women who preferred lumpectomy were more likely to have concordant treatment. Providers tended to emphasize lumpectomy and its advantages in discussions with patients.
See more of: The 33rd Annual Meeting of the Society for Medical Decision Making