Table 2.
Comparison of cognitive performance and subjective symptoms for breast cancer survivors (n = 498) and healthy controls (n = 394)
| Cognitive domain, objective neuropsychological tests and subjective memory | BCS | HC | Difference (BCS-HC) | −1.5 SD | −2.0 SD | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| N | Adjusted mean (95% CI) | N | Adjusted mean (95% CI) | Adjusted mean difference (95% CI) | p value | % BC impaireda | % HC impairedb | % BC impairedc | % HC impairedd | |
| Memory, sum recall, AVLT | 486 | 49.8 (48.5, 51.1) | 374 | 50.1 (48.8, 51.5) | −0.33 (−1.38, 0.72) | .5320 | 7.2 | 4.8 | 1.4 | 2.7 |
| Memory, delayed recall, AVLT | 485 | 9.8 (9.3, 10.2) | 373 | 9.9 (9.4, 10.4) | −0.11 (-0.47, 0.25) | .5465 | 10.3 | 7.2 | 4.7 | 2.4 |
| Attention, concentration, and working memory, digit span | 485 | 18.7 (17.9, 19.4) | 374 | 19.0 (18.2, 19.8) | −0.31 (−0.90, 0.27) | .2952 | 5.4 | 4.6 | 0.2 | 1.3 |
| Speed of processing, symbol digit | 485 | 53.6 (52.2, 55.1) | 374 | 52.6 (51.1, 54.1) | 1.01 (−0.15, 2.16) | .0870 | 3.1 | 4.0 | 0.6 | 1.3 |
| Verbal fluency (COWA) | 485 | 39.0 (37.2, 40.8) | 374 | 39.6 (37.8, 41.5) | −0.61 (−2.02, 0.80) | .3959 | 5.6 | 4.6 | 1.0 | 1.1 |
| Overall neuropsychological test composite* | 485 | −0.3 (−0.5, −0.1) | 374 | −0.2 (−0.4, −0.1) | −0.05 (−0.17, 0.08) | .4590 | 5.4 | 6.2 | 2.1 | 1.3 |
| Self-reported memory, SSMQ | 485 | 88.7 (85.3, 92.0) | 374 | 100.8 (97.2, 104.3) | −12.06 (−14.74, -9.37) | <.0001*** | 22.5 | 5.4 | 11.3 | 1.6 |
Notes: Estimates were obtained from a general linear model adjusted for current age, race, years of education, and income level. p value indicates comparison of adjusted means for younger BCS vs. HC (two-sided partial t-test). Higher cognitive scores indicate better performance on objective tests (AVLT, digit span, symbol digit, COWA, composite). Higher scores indicate better memory on the SSMQ
*p < .05, **p < .01, ***p < .001
a, bCognitive impairment calculated as a standardized residual (observed score minus predicted score) less than −1.5, using predicted values from a control-group demographic-adjusted equation, and dividing the residual by the control group SD
c, dCognitive impairment calculated as a standardized residual (observed score minus predicted score) less than −2.0, using predicted values from a control-group demographic-adjusted equation, and dividing the residual by the control group SD
*Composite calculated by taking average score of all 5 memory variables (AVLT sum recall, AVLT delayed, digit span, symbol digit, and COWA) after Z score standardization (mean = 0, SD = 1) using the control group mean and SD
Significant findings were highlighted in bold; p-values were inserted in the table notes and * inserted with significant values