Smoking bad for HR+ breast cancer

Longtermsurvivor

Locked behind a paywall - oh well! ~ Stephanie

Epidemiology

British Journal of Cancer (2016) 115, 382–390. doi:10.1038/bjc.2016.174 www.bjcancer.com
Published online 9 June 2016

Impacts of smoking on endocrine treatment response in a prospective breast cancer cohort

Mia Persson¹, Maria Simonsson¹, Andrea Markkula¹, Carsten Rose², Christian Ingvar³ and Helena Jernström¹

1. ¹Department of Clinical Sciences, Lund, Division of Oncology and Pathology, Lund University, Barngatan 2B, 22185 Lund, Sweden
2. ²CREATE Health and Department of Immunotechnology, Lund University, Medicon Village (Building 406), 223 81 Lund, Sweden
3. ³Department of Clinical Sciences, Lund, Division of Surgery, Lund University and Skåne University Hospital, 22185 Lund, Sweden

Correspondence: Dr H Jernström, E-mail: Helena.Jernstrom@med.lu.se

Received 16 November 2015; Revised 11 May 2016; Accepted 16 May 2016
Advance online publication 9 June 2016

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Abstract

background:

The association between smoking and breast cancer prognosis remains unclear. The purpose of this study was to investigate whether preoperative smoking was associated with prognosis in different treatment groups.

methods:

This population-based cohort consisted of 1065 breast cancer patients without preoperative treatment included between 2002 and 2012 in Lund, Sweden. Smoking status was examined in relation to patient and tumour characteristics, and prognosis in different treatment groups.

results:

At the preoperative visit, 21.0% smoked. Median follow-up time was 5.1 years. Overall, in the 1016 patients included in the survival analyses, there was no significant association between smoking and risk of breast cancer events (adjusted hazard ratio (adjHR): 1.45; 95% confidence interval (CI): 0.95–2.20). For the 309 aromatase inhibitor (AI)-treated patients 50 years with oestrogen receptor-positive (ER+) tumours, smoking was associated with risk of breast cancer events (adjHR: 2.97; 95% CI: 1.44–6.13), distant metastasis (adjHR: 4.19; 95% CI: 1.81–9.72), and death (adjHR: 3.52; 95% CI: 1.59–7.81). Smoking was not associated with breast cancer events or distant metastasis in other treatment groups.

conclusions:

Preoperative smoking was only associated with an increased risk for breast cancer events and distant metastasis in AI-treated patients. If confirmed, smoking status should be taken into consideration when selecting an endocrine therapy.

Keywords:

breast cancer; smoking; endocrine treatment; aromatase inhibitor; tamoxifen; prognosis

http://www.nature.com/bjc/journal/v115/n3/abs/bjc2...

Fallleaves

This is interesting. I seem to recall reading that smoking is an aromatase inhibitor itself. So maybe it blocks the action of the drugs. But you would think it would still be doing some good (breast cancer-wise) itself.

Also, interesting that they said, " there was no significant association between smoking and risk of breast cancer events (adjusted hazard ratio (adj HR): 1.45)." I guess a 45% increased risk of BC didn't reach the level of significance. Seems odd, but that's statistics for you.

There was another study that did find a significant risk of BC in young women smokers, but only for ER+ BC:

"The researchers found that young women who were current or recent smokers and had been smoking a pack a day for at least 10 years had a 60 percent increased risk of estrogen receptor positive breast cancer. In contrast, smoking was not related to a woman's risk of triple-negative breast cancer.

https://www.sciencedaily.com/releases/2014/02/1402...

Well, plenty of good reasons to discourage smoking and to find ways to help women (and men) quit!

(edited to add this one, too)

"...a large study of breast cancer survivors has found that those who quit smoking after their diagnosis had a 33 percent lower risk of death as a result of breast cancer than those who continued to smoke."

https://www.sciencedaily.com/releases/2016/01/1601...