In this first report of the WISC Study, we found that women tended to gain weight, quit smoking, increase use of NSAIDs and antidepressants, and dramatically decrease use of postmenopausal hormones following a DCIS diagnosis. Little difference in alcohol or fruit and vegetable consumption was detected after diagnosis.
Women tended to report a heavier body weight following their DCIS diagnosis than their recalled body weight at 1 year prior to diagnosis even after adjusting for the changes in weight associated with aging. The difference in weight was most pronounced within the first 4 years after diagnosis. These findings are similar to those reported by the Health, Eating, Activity, and Lifestyle (HEAL) study [23
], in which breast carcinoma in situ survivors (N
= 127) gained 1.3 kg on average between 1 and 3 years post-diagnosis. These results suggest that weight gain after a DCIS diagnosis may tend to be somewhat less than that previously reported for invasive breast cancer survivors [24
]. This difference may be due to differences in the physiological or psychological impacts of in situ and invasive breast cancer diagnoses, as well as differences in the type of treatment received. In the Women’s Healthy Eating and Living Study [25
], invasive breast cancer survivors were more 1.65 times more likely to gain weight (≥5% of body weight) if they received chemotherapy. A smaller weight gain among DCIS survivors would thus be consistent with the rare use of chemotherapy in the treatment of DCIS (<1% in this population).
Tamoxifen has been associated with weight gain in some [26
] but not all [28
] controlled clinical trials in breast cancer survivors and high risk women. We observed somewhat greater weight gain following diagnosis among women who had used tamoxifen, though substantial weight gain was also observed in women who had not. The relative contributions of changes in metabolism rates, physical activity levels, and dietary intake to weight gain after a breast cancer diagnosis remain unclear [30
]. In the HEAL study [31
], women with breast carcinoma in situ decreased their vigorous physical activity levels following their diagnosis. It has also been reported that survivors diagnosed with breast carcinoma in situ engage in lower levels of total physical activity after diagnosis than those with invasive breast cancer [32
]. Ligibel et al. [33
] recently reported that physical activity levels among 391 DCIS survivors were lower among women who underwent mastectomy and women who reported higher anxiety levels. Unfortunately we were unable to compare physical activity levels before and after a DCIS diagnosis in our study, as physical activity was assessed differently at the initial and follow-up interviews.
We observed little change in alcohol or fruit and vegetable consumption after a DCIS diagnosis. Thomson et al. [34
] previously reported that 57% of women who consumed alcohol prior to an invasive breast cancer diagnosis reported decreasing their consumption following diagnosis. A few studies have reported that up to 70% of invasive breast cancer survivors report increasing their fruit and vegetable consumption after diagnosis [32
]. In contrast, Wayne et al. [36
] reported no change in mean intake of fruits and vegetables between 1 year prior and 2 years after a breast carcinoma in situ or invasive breast cancer diagnosis. Variation in the assessment of change in diet is likely to account for variation between studies [36
We found a large fraction of women quit smoking after diagnosis, yet a substantial number (~8%) of DCIS survivors remained smokers. These results are generally similar to the reductions in smoking observed after an invasive breast cancer diagnosis [24
Only 3% of DCIS survivors reported post-diagnosis use of postmenopausal hormones. Notably, use of postmenopausal hormones in the general population has declined since the publication in 2002 of the results of the Women’s Health Initiative randomized trial [38
]. However, the decline in hormone use following a DCIS diagnosis was independent of this secular trend. In analyses restricted to 2003–2006, postmenopausal hormone use was 91% lower among women after a DCIS diagnosis compared to pre-diagnosis reports during the same time period.
We observed elevated use of NSAIDs and antidepressants among women following a DCIS diagnosis compared to the recalled level of use pre-diagnosis. Both of these trends suggest that DCIS diagnosis and treatment may lead to health effects which require pharmacologic intervention. The LACE study has previously reported that 22.6% of invasive breast cancer survivors used NSAIDs after diagnosis [39
] and the HEAL study found that 15% of breast cancer survivors (in situ and invasive combined) were taking antidepressants [40
]. Chubak et al. [41
] found that antidepressant use among invasive breast cancer survivors rose from 23% in 1990 to 36% in 1999, while only 14% of these survivors had used antidepressants in the year prior to their diagnosis. Elevated rates of depression have been observed among breast cancer survivors, with a reported prevalence ranging as high as 46% [42
]. Some antidepressants (e.g., selective serotonin reuptake inhibitors) can also provide relief from menopausal symptoms, potentially explaining the particularly common use of antidepressants we observed among DCIS survivors treated with tamoxifen.
A number of limitations should be considered in the interpretation of this study. While participation in the initial and re-contact interviews was excellent (≥78% of eligible), it remains possible that women who participated had more healthy lifestyles or differed in other ways from those who refused to participate. Eligible women with DCIS who did not complete a follow-up interview were less likely to have a college diploma (20%) and more likely to be a smoker (20%) at the initial interview, but were similar to participants in regard to age, body weight, and family history of breast cancer.
We relied upon self reports of all health-related behaviors. In separate sub-studies we have found that reliability of this self-reported data is good. Among women who were re-interviewed, we found intraclass correlation coefficients >0.75 for body weight and alcohol consumption, and Cohen’s κ ranging from 0.59 for NSAID use to 0.91 for smoking status (see “Methods” for further details). However, the validity of this self-reported data in our population has not been assessed. In addition, it is possible that women with DCIS may artificially alter their response to conform to an expected change in certain behaviors following diagnosis.
Health-related behaviors at 1 year prior to diagnosis were assessed in interviews conducted approximately 1 year after diagnosis. On average, this required subjects to recall behaviors from 2 years past. This reliance on recall likely contributed to measurement error in the pre-diagnosis behaviors. Beyond the typical measurement error inherent in recall over such a period of time, it is possible that the DCIS diagnosis may have clouded the subject’s perception of their pre-diagnosis behaviors. Unfortunately, we have little evidence to assess the potential magnitude or direction of this bias. Finally, our assessment of dietary intake of alcohol and fruits and vegetables was not in the context of a full diet assessment (e.g., food frequency questionnaire) and may therefore be insensitive to true changes in dietary patterns.
Important strengths of the study include the large, population-based sample and the assessment of health-related behaviors for up to 11 years of follow-up after the initial diagnosis.
The influence of changes in health-related behaviors on risk of recurrence after a DCIS diagnosis is currently unknown. The limited data regarding risk of recurrence after an invasive breast cancer diagnosis suggests that post-diagnosis weight gain [43
] and postmenopausal hormone use [44
] increase risk of recurrence, while use of NSAIDs [39
] may lower recurrence rates. Smoking has been associated with all-cause mortality among breast cancer survivors, though it has not been associated with breast cancer specific mortality or risk of recurrence [37
]. Notably, some new antidepressants inhibit the cytochrome P450 enzyme CYP2D6, which metabolizes tamoxifen to its most active metabolite [45
]. We observed that 26% of women treated with tamoxifen also reported post-diagnosis use of antidepressants. Fortunately, the limited evidence to date suggests no impact of antidepressant use on recurrence after a breast cancer diagnosis [41
]. However, there remains a need for further studies with long follow-up periods to confirm this conclusion.
Women with DCIS represent a growing cancer survivor population with a long life expectancy following their diagnosis. Relative survival among DCIS cases approaches that of women without breast cancer [6
], yet the psychological impact of a DCIS diagnosis appears similar to that of a localized invasive breast cancer diagnosis [5
]. This may present a unique opportunity in which women are highly motivated to adopt lifestyle changes which could lower their risk of future breast cancer diagnoses and improve other health outcomes. This cohort will continue to be monitored to investigate the relation between health-related behaviors and risk of recurrence and other health outcomes after a DCIS diagnosis.