Abstract 2298: Antibiotic use and breast cancer risk: results from the Sister Study Conferences uri icon

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abstract

  • Abstract Background: Regular antibiotic use is hypothesized to influence breast cancer risk by a number of mechanisms including disruption of intestinal microflora which plays a role in the conversion of food-based phytochemicals into bioactive substances suggested to be protective against cancer, and by influences on the immune system and inflammatory response.  Previous results have been mixed, and given the sparse and conflicting data in epidemiologic literature, we analyzed the association between regular antibiotic use and breast cancer risk, overall and by different classes of antibiotics. Methods: Regular antibiotic use, as characterized by class type and number, duration, and indication for use, was evaluated for its association with breast cancer risk among participants of the NIEHS Sister Study, a prospective cohort of 50,884 US women aged 35-74 without breast cancer who have had a sister diagnosed with breast cancer. Results: 5,312 (10.4%) of women in the Sister Study reported ever having regular antibiotic use (at least 3 times per week for 3 months in a row or longer) with a median duration of 1.50 years (0.25 – 53.8). 34% of regular uses reported use greater than 2 years. Skin conditions including acne and rosacea were the most common indications for use (6.02%). The hazard ratio (HR) was 1.10 (0.99-1.27) for ever regular antibiotic use and 1.40 (1.16-1.69) for greater than 2 years of regular use. Results are suggestive of an increased risk among regular users who have only ever used one class rather than more than one class of antibiotics. Adjusted hazard ratios were 1.40 (0.99-1.99) for tetracyclines only, 1.45 (0.95-2.20) for penicillins only, 1.42 (0.94-2.15) for macrolides alone. However, there does not appear to be an association between ever regular use of more than one class of antibiotics and breast cancer. Furthermore, there was no association between indications for ever regular use and breast cancer risk, among all women reporting regular use of antibiotics, regardless of class. Conclusion: Overall, there is a suggestion that ever regular use of a single class of antibiotics, but not use of more than one class, may be associated with increased breast cancer risk. However, given that most individuals reported only a single episode of regular antibiotic use for a duration of less than 2 years; further exploration is warranted to rule out effects of underlying indication for use or explore other possible class specific-confounders. Citation Format: Sandra L. Deming-Halverson, M. Elizabeth Hodgson, Aimee D'Aloisio, David Shore, Dale Sandler. Antibiotic use and breast cancer risk: results from the Sister Study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2298. doi:10.1158/1538-7445.AM2017-2298

authors

  • Deming-Halverson, Sandra L
  • Hodgson, M Elizabeth
  • D'Aloisio, Aimee
  • Shore, David I
  • Sandler, Dale

publication date

  • July 1, 2017