Demographic and clinical characteristics of women with early stage breast cancer are shown by geographic area (). Most participants were 50–69 years of age. Women from Los Angeles were more likely to have positive lymph nodes, larger tumors, and negative estrogen receptors than women from the other two sites. They were also more likely to have no comorbidities recorded in their hospital medical record. However, all women from Los Angeles County were Black and, on average, they were younger.
Demographic and Clinical Characteristics of Total HEAL Population of Women Diagnosed with Non-Distant Breast Cancer by Registry
Breast Cancer Participants’ Comorbidities at Diagnosis vs. Matched controls
We compared conditions reported by breast cancer patients with an age, race/ethnicity, and education matched population-based sample of women without cancer (). Hypertension was the most commonly reported comorbidity in both groups. However, it was reported significantly less often in the hospital record (28%) than the NHANES data (34%) (p<0.05). HEAL participants’ reports of osteoporosis before breast cancer diagnosis (7%) were not significantly higher than the matched control group (4%). The hospital record (8%) and the pre-diagnosis report of diabetes (8%) were similar in breast cancer patients and in women without cancer (8%). Gallbladder disease was reported significantly more often by women in NHANES (16%) than by breast cancer patients pre-diagnosis (11%) (p=<0.05). Thyroid disease was recorded significantly less often in the medical record compared to self-reported pre-diagnosis (17%) (p<0.05) and reported nearly half as often in the NHANES sample (9%) than by breast cancer patients (p<0.05). Although angina/chest pain was reported much more frequently in the NHANES sample, the questions were not asked in the same way on the two surveys. The women in the NHANES sample were asked “have you ever had;” in the HEAL cohort, the question was, “has a doctor ever told you.”
Percentage of HEAL participants with comorbid conditions from the baseline hospital record, the 24 month survey and the percentage of participants in the National Health and Nutrition Examination Survey (NHANES III) reporting the condition
Comorbidity at diagnosis
The most commonly reported comorbid condition among breast cancer patients was hypertension (). Nearly 28% of the patients’ hospital records and 30% of the patient pre-diagnostic self-reports indicate hypertension, a non-significant difference. Arthritis was the second most frequently reported condition in the hospital record and in the self-reported pre-diagnostic conditions. However, it was recorded less than half as often in the hospital record (p=<0.05). From the hospital record and the retrospectively collected pre-diagnosis conditions reported by the breast cancer patients chronic lung disease, diabetes and congestive heart failure were reported with similar frequency (). Although nearly twice as many women reported being told by a doctor that they had had a heart attack as was found in the hospital record, the difference was not statistically significant. Kidney disease was less often recorded in the hospital record than reported by HEAL participants (p=<0.05). We found that the prevalence of most of the conditions increased substantially with age regardless of the data source (data not shown).
Pre-diagnostic Comorbidities and Therapy
Type of therapy for breast cancer varied by geographic region (). Women in Western Washington more often received BCS than did women in Los Angeles. The use of radiation was lower in Los Angeles. Most women did not receive chemotherapy. Women in Los Angeles were significantly more likely to receive chemotherapy and women in Western Washington were more frequently prescribed tamoxifen. Slightly over 26% of patients received tamoxifen with no chemotherapy (data not shown). More than 6% received 5-FU, cyclophosphamide, and methotrexate with an additional 6% receiving the same 3 agents plus tamoxifen. Nearly 5% received cyclophosphamide plus doxorubicin and another 5% cyclophosphamide, doxorubicin plus Tamoxifen. Less than 1% of patients refused adjuvant therapies.
Percentage of Women Diagnosed with Non-Distant Breast Cancer Receiving Primary and Adjuvant Therapy by Registry
In multivariable regression, after adjusting for age, geographic location, stage, estrogen receptor status, congestive heart failure significantly affected therapy (data not shown). Among women who had BCS those with congestive heart failure recorded in their hospital medical record were significantly less likely (p<0.01) to receive radiation following BCS. Women with invasive breast cancer and congestive heart failure were also less likely to receive chemotherapy (P<0.01).
New comorbidites following diagnosis
Increased comorbidity following the diagnosis and treatment of breast cancer is of concern. Arthritis was the most frequently self-reported comorbidity to be newly diagnosed in the time period between the diagnosis of breast cancer and the follow-up survey (). Osteoporosis and hypertension were the next most frequent.
We examined comorbidities reported by participants following the diagnosis of breast cancer by type of therapy (). Arthritis was the most frequently diagnosed new comorbidity among all types of therapy. Hypertension and osteoporosis were the next most frequently diagnosed conditions. Although the ordering of the conditions was similar, a smaller percentage of women who received no adjuvant therapy were diagnosed with the new conditions.
Self-reported Comorbid Conditions Newly Diagnosed Following the Diagnosis of Breast Cancer*
In multivariate models to determine factors associated with the diagnosis of new comorbid conditions older age was a strong predictor of new comorbid conditions reported by women following breast cancer diagnosis (). In addition, women treated with chemotherapy only (OR = 3.2, 95% CI 1.5, 6.8) were significantly more likely than women who received no adjuvant therapy to report a new post-diagnosis comorbid condition. This variable remained significant when we excluded the number of comorbid conditions pre-diagnosis and stage at diagnosis from the model (OR = 2.8, 95% CI 1.4, 5.5). Women treated with chemotherapy plus radiation (OR = 1.9, 95% CI 1.02, 3.7) or radiation plus tamoxifen (OR=1.9, 95% CI 1.1, 3.2) were at increased risk of new post-diagnosis comorbidities compared with women receiving none of these therapies. The use of chemotherapy plus tamoxifen (p = 0.08) and chemotherapy plus radiation plus tamoxifen (p = 0.06) were positively associated with new comorbidities, but these did not reach statistical significance. Neither the use of radiation alone (p=0.27) nor tamoxifen alone (p=0.35) was significantly associated with new post-diagnosis comorbidities. Geographic area, stage at diagnosis and number of pre-diagnostic conditions were not significantly associated with subsequent comorbidities.
Clinical and Non-clinical Characteristics Associated with Self-reported Post-Breast Cancer Diagnosis of Comorbid Conditions in Early Stage Breast Cancer Patients
We excluded women who had a breast cancer recurrence or who were diagnosed with a new primary cancer from this model to identify factors associated with new comorbid conditions. The association between use of chemotherapy (OR = 2.4, CI 1.03, 5.4) and radiation plus tamoxifen (OR= 1.8, 1.04, 3.0) and the diagnosis of new comorbidities remained significant. Although still positive, chemotherapy plus radiation (p =0.07) was no longer statistically significant.
We also examined the association between therapy, stage, age, and geographic area and the self-reported diagnosis of new comorbid conditions in women who had no comorbid conditions recorded in their hospital record at treatment or self-reported before diagnosis (n=223). All therapies were positively associated with the self-reported diagnosis of new conditions, but none reach statistical significance. Age was no longer significant.