Pre- and postoperative alcohol consumption in breast cancer patients: impact on early events

Abstract

Purpose: To investigate the association between pre- and postoperative alcohol consumption and risk for early breast cancer events, since the association between alcohol consumption and prognosis in breast cancer patients is unclear.

Methods: Alcohol consumption was recorded for 934 primary breast cancer patients who underwent breast cancer surgery in Lund, Sweden, between 2002 and 2011 and were followed until December 31(st) 2012. Clinical data were obtained from medical records and population registries. Pre- and postoperative alcohol consumption was analyzed in relation to risk for early events.

Results: Median follow-up time was 3.03 years and 100 breast cancer events, 65 distant metastases, and 76 deaths occurred. Compared to no consumption, any preoperative alcohol consumption was weakly associated with lower risk for early events, adjusted HR 0.69 (0.45-1.04), distant metastases, 0.60 (0.36-1.00) and death, 0.62 (0.38-1.01). In the 572 patients without axillary lymph node involvement, any alcohol consumption was not associated with risk for early events. However, in the 360 patients with axillary lymph node involvement, preoperative alcohol consumption was associated with lower risk for early events (adjusted HR 0.43 0.24-0.77; P interaction = 0.01).

Conclusion: Pre- and postoperative alcohol consumption was weakly associated with lower risk for early breast cancer events. The data does not support recommending that all breast cancer patients abstain from low to moderate alcohol consumption.

Keywords: Alcohol consumption; Breast cancer; Death; Early breast cancer events; Early distant metastases.

Figure 1

Flowchart illustrating the inclusion and exclusion criteria for patients in the different analyses.

Figure 2

A-C Preoperative alcohol consumption in relation to early events, including local or regional recurrence, new breast cancer, or distant metastases, in: A) All patients – adjusted HR 0.55 (95% CI 0.34-0.91) for 1-3 drinks/week, adjusted HR 0.90 (95% CI 0.55-1.48) for 4-9 drinks/week, and adjusted HR 0.71 (95% CI 0.21-2.32) for 10+ drinks/week. Adjusted HR for any alcohol consumption: 0.69 (95% CI 0.45-1.04). B) Patients with axillary lymph node involvement. – adjusted HR 0.38 (95% CI 0.19-0.77) for 1-3 drinks/week, adjusted HR 0.52 (95% CI 0.25-1.07) for 4-9 drinks/week, and adjusted HR 0.33 (95% CI 0.04-2.55) for 10+ drinks/week. There were no events in the group with 10+ drinks/week. Adjusted HR for any alcohol consumption: 0.43 (95% CI 0.24-0.77). C) Patients without axillary lymph node involvement – adjusted HR 0.93 (95% CI 0.44-1.94) for 1-3 drinks/week, adjusted HR 1.81 (95% CI 0.87-3.75) for 4-9 drinks/week, and adjusted HR 1.28 (95% CI 0.28-5.82) for 10+ drinks/week. Adjusted HR for any alcohol consumption: 1.24 (95% CI 0.66-2.34). Since this is an on-going cohort, the number of patients decreases as the follow-up time increases.

Figure 3

A-B Unadjusted and adjusted conditional HR:s for alcohol use. The figures show estimated hazard ratios (HR), with 95% point wise confidence intervals (CI), for alcohol use (yes vs no) from a series of Cox-regression analyses of time from the preoperative visit to any breast cancer event. Each dot corresponds to an analysis conditional on event-free survival up to the corresponding observed visit time. Crude (unadjusted) estimates are shown in Figure 3A and adjusted estimates in Figure 3B. The panels show, from left to right, analyses for all patients, axillary lymph node negative (N0), and axillary lymph node positive (N+) patients, respectively. The number of patients at risk in each of the two groups at time of diagnosis and four years post-operatively is shown below each panel, and the corresponding number of events observed is shown between parentheses. The reason why the counts in N0 and N + in Figure 3A do not sum to the counts for all patients in the group who report no alcohol use is that the axillary lymph node status is unknown for two patients.