Risk of heart failure after systemic treatment for early breast cancer: results of a cohort study.

PURPOSE: Anthracyclines and trastuzumab can increase the risk of heart failure (HF), but long-term cardiotoxicity data in breast cancer (BC) patients treated at younger ages are limited. Furthermore, it is unknown whether aromatase inhibitors are associated with HF risk. METHODS: HF risk was studied in a multicenter cohort of BC survivors treated during 2000-2009, at age < 61 years. Information on treatment and cardiovascular disease incidence was collected through medical records, general practitioners and cardiologists. Analyses included multivariable Cox regression and cumulative incidence curves. RESULTS: In total, 10,209 women with a median age at BC diagnosis of 50.3 years and a median follow-up of 8.9 years were enrolled in the study. Anthracycline-based chemotherapy was associated with HF (hazard ratio [HR] 2.18, 95% confidence interval [CI] 1.41-3.39) and risk increased with increasing cumulative anthracycline dose. For trastuzumab, HF risk was highest within the first 2 years after treatment (HR0-2 years: 13.06, 95% CI 5.70-29.92) and decreased thereafter (HR2-4 years: 4.84, 95% CI 1.99-11.75 and HR≥4 years: 0.64, 95% CI 0.23-1.81). The 10-year cumulative incidence of HF was 4.8% (95% CI 3.2-6.8) among patients treated with anthracyclines and trastuzumab. One-third of patients who developed HF after trastuzumab had long-term impaired cardiac function. Patients treated with aromatase inhibitors alone also had higher HF risk (HR 2.18, 95% CI 1.24-3.82) compared to patients not receiving endocrine therapy. CONCLUSIONS: Our results stress the importance of considering anthracycline-free regimens in BC patients who need trastuzumab-containing treatment. The association between aromatase inhibitors and HF needs confirmation.

Cardiovascular disease incidence after internal mammary chain irradiation and anthracycline-based chemotherapy for breast cancer.

BACKGROUND: Improved breast cancer (BC) survival and evidence showing beneficial effects of internal mammary chain (IMC) irradiation underscore the importance of studying late cardiovascular effects of BC treatment. METHODS: We assessed cardiovascular disease (CVD) incidence in 14,645 Dutch BC patients aged <62 years, treated during 1970-2009. Analyses included proportional hazards models and general population comparisons. RESULTS: CVD rate-ratio for left-versus-right breast irradiation without IMC was 1.11 (95% CI 0.93-1.32). Compared to right-sided breast irradiation only, IMC irradiation (interquartile range mean heart doses 9-17 Gy) was associated with increases in CVD rate overall, ischaemic heart disease (IHD), heart failure (HF) and valvular heart disease (hazard ratios (HRs): 1.6-2.4). IHD risk remained increased until at least 20 years after treatment. Anthracycline-based chemotherapy was associated with an increased HF rate (HR = 4.18, 95% CI 3.07-5.69), emerging <5 years and remaining increased at least 10-15 years after treatment. IMC irradiation combined with anthracycline-based chemotherapy was associated with substantially increased HF rate (HR = 9.23 95% CI 6.01-14.18), compared to neither IMC irradiation nor anthracycline-based chemotherapy. CONCLUSIONS: Women treated with anthracycline-based chemotherapy and IMC irradiation (in an older era) with considerable mean heart dose exposure have substantially increased incidence of several CVDs. Screening may be appropriate for some BC patient groups.

Omitting re-excision for focally positive margins after breast-conserving surgery does not impair disease-free and overall survival.

PURPOSE: In contrast to other countries, the Dutch breast cancer guideline does not recommend re-excision for focally positive margins after breast-conserving surgery (BCS) in invasive tumor and does recommend whole-breast irradiation including boost. We investigated whether omitting re-excision as compared to performing re-excision affects prognosis with a retrospective population-based cohort study. METHODS: The total cohort included 32,119 women with primary BCS for T1-T3 breast cancer diagnosed between 2003 and 2008 from the nationwide Netherlands cancer registry. The subcohort included 10,433 patients in whom the resection margins were registered. Outcome measures were 5-year ipsilateral breast tumor recurrence (IBTR) rate, 5-year disease-free survival (DFS) rate, and 10-year overall survival (OS) rate. RESULTS: In the total cohort, 25,878 (80.6%) did not have re-excision, 2368 (7.4%) had re-excision by BCS, and 3873 (12.1%) had re-excision by mastectomy. Five-year IBTR rates were 2.1, 2.8, and 2.9%, respectively (p = 0.001). In the subcohort, 7820 (75.0%) had negative margins without re-excision, 492 (4.7%) had focally positive margins without re-excision, 586 (5.6%) had focally positive margins and underwent re-excision, and 1535 (14.7%) had extensively positive margins and underwent re-excision. Five-year IBTR rate was 2.3, 2.9, 1.1, and 2.9%, respectively (p = 0.099). Compared to omitting re-excision, performing re-excision for focally positive margins was associated with lower risk of IBTR (adjusted HR 0.30, 95% CI 0.11-0.82), but not with DFS (adjusted HR 0.83 95% CI 0.59-1.17) nor with OS (adjusted HR 1.17 95% CI 0.87-1.59). CONCLUSION: Omitting re-excision in breast cancer patients for focally positive margins after BCS does not impair DFS and OS, provided that whole-breast irradiation including boost is given.

Extent of ductal carcinoma in situ according to breast cancer subtypes: a population-based cohort study.

Ductal carcinoma in situ (DCIS) is a precursor of invasive breast carcinoma (IBC). The DCIS component is often more extensive than the invasive component, which affects local control. The aim of our study was to analyze features of DCIS within different IBC subtypes, which may contribute to the optimization of personalized approaches for patients with IBC. Patients with IBC reported according to the synoptic reporting module in the Netherlands between 2009 and 2015 were included. Data extraction included characteristics of the invasive component and, if present, several features of the DCIS component. Resection margin status analyses were restricted to patients undergoing breast-conserving surgery (BCS). Differences between subtypes were tested by a Chi-square test, spearman's Rho test or a one-way ANOVA test. Overall, 36.937 cases of IBC were included. About half of the IBCs (n = 16.014; 43.4 %) were associated with DCIS. Her2+ IBC (irrespective of ER status) was associated with a higher prevalence of adjacent DCIS, a larger extent of DCIS and a higher rate of irradicality of the DCIS component as compared to ER+/Her2- and triple-negative subtypes (P < 0.0001 for all variables). The prevalence of DCIS in triple-negative IBC on the other hand was lowest. In this large population-based cohort study, we showed significant differences between the prevalence and extent of DCIS according to IBC subtypes, which is also reflected in the resection margin status in patients treated with BCS. Our data provide important information regarding the optimization of local therapy according to IBC subtypes.

Breast conserving therapy versus mastectomy for stage I-II breast cancer: 20 year follow-up of the EORTC 10801 phase 3 randomised trial.

BACKGROUND: The EORTC 10801 trial compared breast-conserving therapy (BCT) with modified radical mastectomy (MRM) in patients with tumours 5 cm or smaller and axillary node negative or positive disease. Compared with BCT, MRM resulted in better local control, but did not affect overall survival or time to distant metastases. We report 20-year follow-up results. METHODS: The EORTC 10801 trial was open for accrual between 1980 and 1986 in eight centres in the UK, the Netherlands, Belgium, and South Africa. 448 patients were randomised to BCT and 420 to MRM. Randomisation was done centrally, stratifying patients by institute, carcinoma stage (I or II), and menopausal status. BCT comprised of lumpectomy and complete axillary clearance, followed by breast radiotherapy and a tumour-bed boost. The primary endpoint was time to distant metastasis. This analysis was done on all eligible patients, as they were randomised. FINDINGS: After a median follow-up of 22·1 years (IQR 18·5-23·8), 175 patients (42%) had distant metastases in the MRM group versus 207 (46%) in the BCT group. Furthermore, 506 patients (58%) died (232 [55%] in the MRM group and 274 [61%] in the BCT group). No significant difference was observed between BCT and MRM for time to distant metastases (hazard ratio 1·13, 95% CI 0·92-1·38; p=0·23) or for time to death (1·11, 0·94-1·33; 0·23). Cumulative incidence of distant metastases at 20 years was 42·6% (95% CI 37·8-47·5) in the MRM group and 46·9% (42·2-51·6) in the BCT group. 20-year overall survival was estimated to be 44·5% (95% CI 39·3-49·5) in the MRM group and 39·1% (34·4-43·9) in the BCT group. There was no difference between the groups in time to distant metastases or overall survival by age (time to distant metastases: <50 years 1·09 [95% CI 0·79-1·51] vs ≥50 years 1·16 [0·90-1·50]; overall survival <50 years 1·17 [0·86-1·59] vs ≥50 years 1·10 [0·89-1·37]). INTERPRETATION: BCT, including radiotherapy, offered as standard care to patients with early breast cancer seems to be justified, since long-term follow-up in this trial showed similar survival to that after mastectomy. FUNDING: European Organisation for Research and Treatment of Cancer (EORTC).

Exposure of the heart and cardiac valves in women irradiated for breast cancer 1970-2009.

Purpose: To describe cardiac exposure from breast cancer radiotherapy regimens used during 1970-2009 for the development of dose-response relationships and to consider the associated radiation-risks using existing dose-response relationships. Material and methods: Radiotherapy charts for 771 women in the Netherlands selected for case control studies of heart disease after breast cancer radiotherapy were used to reconstruct 44 regimens on a typical CT-dataset. Doses were estimated for the whole heart (WH), left ventricle (LV) and cardiac valves. Results: For breast/chest wall radiotherapy average WH doses decreased during 1970-2009. For internal mammary chain (IMC) radiotherapy WH doses were highest during the 1980s and 1990s when direct anterior fields were used and reduced in the 2000s when oblique fields were introduced. Average doses varied substantially for IMC regimens (WH 2-33 Gy, LV < 1-23 Gy). For cardiac valves, at least one valve received >30 Gy from most regimens. Conclusions: Radiation-risks of IHD from breast/chest wall regimens likely reduced during 1970-2009. Direct anterior IMC regimens likely increased the risks of IHD and VHD over this time period but the use of oblique IMC fields from 2003 may have lowered these risks. These data provide a unique opportunity to develop dose-response relationships.

Prognosis of acute coronary syndromes after radiotherapy for breast cancer.

BACKGROUND AND PURPOSE: Breast cancer patients treated with radiotherapy are at increased risk of subsequent acute coronary syndromes (ACS). We aimed to study if radiotherapy also influences the prognosis of these ACS. MATERIALS AND METHODS: We included all 398 patients diagnosed with ACS following radiotherapy from our hospital-based cohort of early breast cancer patients aged <71 years, treated 1970-2009. Cardiovascular disease incidence and cause of death were acquired through questionnaires to general practitioners and cardiologists. Internal mammary chain (IMC) irradiation delivers the highest heart doses in breast cancer radiotherapy. Hence, we compared ACS prognosis between patients treated with/without IMC-irradiation. ACS prognosis was assessed through cardiac death, death due to ACS and cardiovascular disease incidence, using multivariable Cox proportional hazard models and by estimating cumulative incidence. RESULTS: In total, 62% of patients with ACS had received IMC-irradiation and 38% did not (median age at ACS diagnosis, 67 years). Median time between breast cancer and ACS was 15 years. After ACS, ten-year cumulative risk of cardiac death was 35% for patients who had IMC-irradiation (95% confidence interval [95%CI] 29-41) compared to 24% (95%CI 17-31) for patients without IMC-irradiation (p = 0.04). After correction for confounders, IMC-irradiation remained associated with a less favourable prognosis of ACS compared to no IMC-irradiation (hazard ratio cardiac death = 1.7, 95%CI 1.1-2.5). CONCLUSION: Our results suggest that radiotherapy, in case of substantial heart doses,may worsen ACS prognosis. This is an important, novel finding that may impact upon the risk-based care for breast cancer survivors with ACS.

Radiation Dose-Response for Risk of Myocardial Infarction in Breast Cancer Survivors.

PURPOSE: Previous reports suggest that radiation therapy for breast cancer (BC) can cause ischemic heart disease, with the radiation-related risk increasing linearly with mean whole heart dose (MWHD). This study aimed to validate these findings in younger BC patients and to investigate additional risk factors for radiation-related myocardial infarction (MI). METHODS AND MATERIALS: A nested case-control study was conducted within a cohort of BC survivors treated during 1970 to 2009. Cases were 183 patients with MI as their first heart disease after BC. One control per case was selected and matched on age and BC diagnosis date. Information on treatment and cardiovascular risk factors was abstracted from medical and radiation charts. Cardiac doses were estimated for each woman by reconstructing her regimen using modern 3-dimensional computed tomography planning on a typical patient computed tomography scan. RESULTS: Median age at BC of cases and controls was 50.2 years (interquartile range, 45.7-54.7). Median time to MI was 13.6 years (interquartile range, 9.9-18.1). Median MWHD was 8.9 Gy (range, 0.3-35.2 Gy). MI rate increased linearly with increasing MWHD (excess rate ratio [ERR] per Gy, 6.4%; 95% confidence interval, 1.3%-16.0%). Patients receiving ≥20 Gy MWHD had a 3.4-fold (95% confidence interval, 1.5-7.6) higher MI rate than unirradiated patients. ERRs were higher for younger women, with borderline significance (ERR<45years, 24.2%/Gy; ERR≥50years, 2.5%/Gy; Pinteraction = .054). Whole heart dose-volume parameters did not modify the dose-response relationship significantly. CONCLUSIONS: MI rate after radiation for BC increases linearly with MWHD. Reductions in MWHD are expected to contribute to better cardiovascular health of BC survivors.

Involved-field radiotherapy for patients in partial remission after chemotherapy for advanced Hodgkin's lymphoma.

PURPOSE: The use of radiotherapy in patients with advanced Hodgkin's lymphoma (HL) is controversial. The purpose of this study was to describe the role of radiotherapy in patients with advanced HL who were in partial remission (PR) after chemotherapy. METHODS: In a prospective randomized trial, patients <70 years old with previously untreated Stage III-IV HL were treated with six to eight cycles of mechlorethamine, vincristine, procarbazine, prednisone/doxorubicin, bleomycine, vinblastine hybrid chemotherapy. Patients in complete remission (CR) after chemotherapy were randomized between no further treatment and involved-field radiotherapy (IF-RT). Those in PR after six cycles received IF-RT (30 Gy to originally involved nodal areas and 18-24 Gy to extranodal sites with or without a boost). RESULTS: Of 739 enrolled patients, 57% were in CR and 33% in PR after chemotherapy. The median follow-up was 7.8 years. Patients in PR had bulky mediastinal involvement significantly more often than did those in CR after chemotherapy. The 8-year event-free survival and overall survival rate for the 227 patients in PR who received IF-RT was 76% and 84%, respectively. These rates were not significantly different from those for CR patients who received IF-RT (73% and 78%) or for those in CR who did not receive IF-RT (77% and 85%). The incidence of second malignancies in patients in PR who were treated with IF-RT was similar to that in nonirradiated patients. CONCLUSION: Patients in PR after six cycles of mechlorethamine, vincristine, procarbazine, prednisone/doxorubicine, bleomycine, vinblastine treated with IF-RT had 8-year event-free survival and overall survival rates similar to those of patients in CR, suggesting a definite role for RT in these patients.

Diagnostic and therapeutic ionizing radiation and the risk of a first and second primary breast cancer, with special attention for BRCA1 and BRCA2 mutation carriers: a critical review of the literature.

Occurrence of breast cancer is a well-known long-term side effect of ionizing radiation (both diagnostic and therapeutic). The radiation-induced breast cancer risk increases with longer follow-up, higher radiation dose and younger age of exposure. The risk for breast cancer following irradiation for lymphomas is well known. Although data regarding the carcinogenic risk of adjuvant radiotherapy for a primary breast cancer are sparse, an increased risk is suggested with longer follow-up mainly when exposed at younger age. Particularly, patients with a BRCA1/2 mutation might be more sensitive for the deleterious effects of ionizing radiation due to an impaired capacity of repairing double strand DNA breaks. This might have consequences for the use of mammography in breast cancer screening, as well as the choice between breast conserving therapy including radiotherapy and mastectomy at primary breast cancer diagnosis in young BRCA1/2 mutation carriers. Good data regarding this topic, however, are scarce, mainly due to constraints in the design of performed studies. In this review, we will discuss the current literature on the association between ionizing radiation and developing breast cancer, with particular attention to patients with a BRCA1/2 mutation.

Breast cancer risk in female survivors of Hodgkin's lymphoma: lower risk after smaller radiation volumes.

PURPOSE: We assessed the long-term risk of breast cancer (BC) after treatment for Hodgkin's lymphoma (HL). We focused on the volume of breast tissue exposed to radiation and the influence of gonadotoxic chemotherapy (CT). PATIENTS AND METHODS: We performed a cohort study among 1,122 female 5-year survivors treated for HL before the age of 51 years between 1965 and 1995. We compared the incidence of BC with that in the general population. To assess the risk according to radiation volume and hormone factors, we performed multivariate Cox regression analyses. RESULTS: After a median follow-up of 17.8 years, 120 women developed BC (standardized incidence ratio [SIR], 5.6; 95% CI, 4.6 to 6.8), absolute excess risk 57 per 10,000 patients per year. The overall cumulative incidence 30 years after treatment was 19% (95% CI, 16% to 23%); for those treated before age 21 years, it was 26% (95% CI, 19% to 33%). The relative risk remained high after prolonged follow-up (> 30 years after treatment: SIR, 9.5; 95% CI, 4.9 to 16.6). Mantle field irradiation (involving the axillary, mediastinal, and neck nodes) was associated with a 2.7-fold increased risk (95% CI, 1.1 to 6.9) compared with similarly dosed (36 to 44 Gy) mediastinal irradiation alone. Women with >or= 20 years of intact ovarian function after radiotherapy at young ages (< 31 years) experienced significantly higher risks for BC than those with fewer than 10 years of intact ovarian function. CONCLUSION: Reduction of radiation volume appears to decrease the risk for BC after HL. In addition, shorter duration of intact ovarian function after irradiation is associated with a significant reduction of the risk for BC.

Roles of radiotherapy and chemotherapy in the development of contralateral breast cancer.

PURPOSE: Few studies have examined whether modern radiotherapy and chemotherapy affect the risk of contralateral breast cancer (CBC), and results are inconclusive. PATIENTS AND METHODS: We assessed long-term risk of CBC in a predominantly young breast cancer (BC) population (n = 7,221), focusing on the effects of radiation dose, chemotherapy, and family history of BC. Risk of CBC was evaluated using Cox proportional hazards regression models. RESULTS: Radiotherapy-associated risk of CBC increased with decreasing age at first treatment (age < 35 years, hazard ratio [HR] = 1.78; 95% CI, 0.85 to 3.72; age > 45 years, HR = 1.09; 95% CI, 0.82 to 1.45). Postmastectomy radiotherapy using direct electron fields led to a significantly lower radiation exposure to the contralateral breast than postlumpectomy radiotherapy using tangential fields. Women treated before age 45 years with postlumpectomy radiotherapy experienced 1.5-fold increased risk of CBC compared with those who had postmastectomy radiotherapy. The joint effects of postlumpectomy radiotherapy and strong family history for BC on risk of CBC were greater than expected when individual risks were summed (HR = 3.52; 95% CI, 2.07 to 6.02; P(departure from additivity) = .043). Treatment with adjuvant chemotherapy (cyclophosphamide, methotrexate, and fluorouracil) was associated with a nonsignificantly decreased risk of CBC in the first 5 years of follow-up but did not reduce CBC risk in subsequent years. CONCLUSION: Young patients with BC irradiated with breast tangentials experience increased risk of CBC, especially in those with a positive family history of BC. This finding should be taken into account when advising breast radiation with tangential fields to young patients with BC. Adjuvant chemotherapy seemed to reduce the risk of CBC during the first 5 years after treatment only.

Long-term risk of cardiovascular disease in 10-year survivors of breast cancer.

BACKGROUND: Radiotherapy for breast cancer as delivered in the 1970s has been associated with increased risk of cardiovascular disease, but recent studies of associations with modern regimens have been inconclusive. Few data on long-term cardiovascular disease risk according to specific radiation fields are available, and interaction with known cardiovascular risk factors has not been examined. METHODS: We studied treatment-specific incidence of cardiovascular disease in 4414 10-year survivors of breast cancer who were treated from 1970 through 1986. Risk of cardiovascular disease in these patients was compared with general population rates and evaluated in Cox proportional hazards regression models. All statistical tests were two-sided. RESULTS: After a median follow-up of 18 years, 942 cardiovascular events were observed (standardized incidence ratio = 1.30, 95% confidence interval [CI] = 1.22 to 1.38; corresponding to 62.9 excess cases per 10,000 patient-years). Breast irradiation only was not associated with increased risk of cardiovascular disease. However, radiotherapy to either the left or right side of the internal mammary chain was associated with increased cardiovascular disease risk for the treatment period 1970-1979 (for myocardial infarction, hazard ratio [HR] = 2.55, 95% CI = 1.55 to 4.19; P<.001; for congestive heart failure, HR = 1.72, 95% CI = 1.22 to 2.41; P = .002) compared with no radiotherapy. Among patients who received internal mammary chain radiotherapy after 1979, risk of myocardial infarction declined over time toward unity, whereas the risks of congestive heart failure (HR = 2.66, 95% CI = 1.27 to 5.61; P = .01) and valvular dysfunction (HR = 3.17, 95% CI = 1.90 to 5.29; P<.001) remained increased. Patients who underwent radiotherapy plus adjuvant chemotherapy (cyclophosphamide, methotrexate, and fluorouracil) after 1979 had a higher risk of congestive heart failure than patients who were treated with radiotherapy only (HR = 1.85, 95% CI = 1.25 to 2.73; P = .002). Smoking and radiotherapy together were associated with a more than additive effect on risk of myocardial infarction (HR = 3.04, 95% CI = 2.03 to 4.55; P for departure from additivity = .039). CONCLUSIONS: Radiotherapy as administered from the 1980s onward is associated with an increased risk of cardiovascular disease. Irradiated breast cancer patients should be advised to refrain from smoking to reduce their risk for cardiovascular disease.

Late cardiotoxicity after treatment for Hodgkin lymphoma.

We assessed cardiovascular disease (CVD) incidence in 1474 survivors of Hodgkin lymphoma (HL) younger than 41 years at treatment (1965-1995). Multivariable Cox regression and competing risk analyses were used to quantify treatment effects on CVD risk. After a median follow-up of 18.7 years, risks of myocardial infarction (MI) and congestive heart failure (CHF) were strongly increased compared with the general population (standardized incidence ratios [SIRs] = 3.6 and 4.9, respectively), resulting in 35.7 excess cases of MI and 25.6 excess cases of CHF per 10 000 patients/year. SIRs of all CVDs combined remained increased for at least 25 years and were more strongly elevated in younger patients. Mediastinal radiotherapy significantly increased the risks of MI, angina pectoris, CHF, and valvular disorders (2- to 7-fold). Anthracyclines significantly added to the elevated risks of CHF and valvular disorders from mediastinal RT (hazard ratios [HRs] were 2.81 and 2.10, respectively). The 25-year cumulative incidence of CHF after mediastinal radiotherapy and anthracyclines in competing risk analyses was 7.9%. In conclusion, risks of several CVDs are 3- to 5-fold increased in survivors of HL compared with the general population, even after prolonged follow-up, leading to increasing absolute excess risks over time. Anthracyclines further increase the elevated risks of CHF and valvular disorders from mediastinal radiotherapy.