Dietary Supplement Use During Chemotherapy and Survival Outcomes of Patients With Breast Cancer Enrolled in a Cooperative Group Clinical Trial (SWOG S0221)

PURPOSE

Despite reported widespread use of dietary supplements during cancer treatment, few empirical data with regard to their safety or efficacy exist. Because of concerns that some supplements, particularly antioxidants, could reduce the cytotoxicity of chemotherapy, we conducted a prospective study ancillary to a therapeutic trial to evaluate associations between supplement use and breast cancer outcomes.

METHODS

Patients with breast cancer randomly assigned to an intergroup metronomic trial of cyclophosphamide, doxorubicin, and paclitaxel were queried on their use of supplements at registration and during treatment (n =1,134). Cox proportional hazards regression adjusting for clinical and lifestyle variables was used. Recurrence and survival were indexed at 6 months after enrollment using a landmark approach.

RESULTS

There were indications that use of any antioxidant supplement (vitamins A, C, and E; carotenoids; coenzyme Q10) both before and during treatment was associated with an increased hazard of recurrence (adjusted hazard ratio [adjHR], 1.41; 95% CI, 0.98 to 2.04; P = .06) and, to a lesser extent, death (adjHR, 1.40; 95% CI, 0.90 to 2.18; P = .14). Relationships with individual antioxidants were weaker perhaps because of small numbers. For nonantioxidants, vitamin B12 use both before and during chemotherapy was significantly associated with poorer disease-free survival (adjHR, 1.83; 95% CI, 1.15 to 2.92; P < .01) and overall survival (adjHR, 2.04; 95% CI, 1.22 to 3.40; P < .01). Use of iron during chemotherapy was significantly associated with recurrence (adjHR, 1.79; 95% CI, 1.20 to 2.67; P < .01) as was use both before and during treatment (adjHR, 1.91; 95% CI, 0.98 to 3.70; P = .06). Results were similar for overall survival. Multivitamin use was not associated with survival outcomes.

CONCLUSION

Associations between survival outcomes and use of antioxidant and other dietary supplements both before and during chemotherapy are consistent with recommendations for caution among patients when considering the use of supplements, other than a multivitamin, during chemotherapy.

Variability in visual segmentation of digitized prostate tissue microarray cores

OBJECTIVE

To examine bias associated with human-interactive semi-automated systems key components with machine vision used in quantitative histometry.

STUDY DESIGN

A standard image set of 20 images was created using 5 nuclei sampled from hematoxylin-eosin-stained sections of benign tissue within a prostate tissue microarray that were rotated through the cardinal directions. Four trained technicians performed segmentation of these images at the start, then at the end, of 3 daily sessions, creating a total analytic set of 480 observations. Measurements of nuclear area (NA), nuclear roundness factor (NRF), and mean optical density (MOD) were compared by segmenter, time, and rotational orientation.

RESULTS

NA varied significantly among sessions (p < 0.0009) and session variance differed within segmenter (p < 0.0001). NRF was significant among segmenters (p < 0.001) and sessions (p < 0.0001), and in session (p < 0.0001) and intra-session differences (p = 0.026). Differences in MOD varied among sessions (p < 0.0001) and within sessions (p < 0.049).

CONCLUSION

Imaging systems remain vulnerable to statistical inter-segmenter variation, in spite of extensive efforts to eliminate variation among individual segmenters. As statistical significance often guides decision-making in morphometric analysis, statistically significant effects potentially produce bias. Current practices and quality assurance methods require review to eliminate individual operator effects in semiautomated machine systems.

Dietary patterns related to glycemic index and load and risk of premenopausal and postmenopausal breast cancer in the Western New York Exposure and Breast Cancer Study

BACKGROUND

Reduced rank regression (RRR) has been used to identify dietary patterns that predict variation in a selected risk factor and may be useful in describing dietary exposures associated with glycemic index (GI) and glycemic load (GL).

OBJECTIVE

To estimate breast cancer risk, we compared the relative utility of RRR-derived dietary patterns predictive of GI and GL with those of simple GI and GL.

DESIGN

RRR was used to identify dietary patterns predicting GI and GL from food-frequency data obtained in the Western New York Exposure and Breast Cancer Study (1166 cases, 2105 controls). Odds ratios (ORs) and 95% CIs were estimated with unconditional logistic regression, adjusted for energy and nondietary breast cancer risk factors.

RESULTS

Sweets, refined grains, and salty snacks explained 34% of the variance in GI and 68% of the variance in GL. In general, breast cancer risks were not associated with GI, GL, or dietary pattern score. However, we observed a significant reduction in postmenopausal breast cancer risk with GI and GL pattern scores combined (OR: 0.68; 95% CI: 0.50, 0.93), especially in women with a body mass index (in kg/m(2)) >or=25 (OR: 0.64; 95% CI: 0.44, 0.93). Conversely, in premenopausal women, increased risks were associated with high GL pattern scores only for women with a body mass index >or=25 (OR: 2.21; 95% CI: 1.04, 4.69).

CONCLUSIONS

Although RRR may be useful in studies of diet and disease, our results suggest that RRR dietary patterns based on GI and GL provide similar information regarding the association between breast cancer, GI, and GL.