Decreased Risk of Stroke Among 10-Year Survivors of Breast Cancer

Risk of cerebrovascular disease after cancer diagnosis in the United States

The risk of subsequent cerebrovascular disease among cancer patients of multiple cancers in the US is not well understood. A total of 3,843,261 cancer patients diagnosed from 1975 to 2018, were included from the surveillance, epidemiology, and end results (SEER) database. Standardized mortality ratios (SMRs) and absolute excess risks (AERs) were estimated. The overall cerebrovascular disease SMR was 1.04 (95% CI, 1.03-1.04), and the AER per 10,000 person-years at risk was 0.89. When compared with the US general population, greater cerebrovascular disease risk was correlated with certain cancer sites, American Indian/Alaska Native race, Asian or Pacific Islander race, unmarried marital status, distant metastasis, younger age, and an earlier time of cancer diagnosis. Clinically, more precision and proactive strategies for cerebrovascular disease prevention are required to subgroup of cancer patients with a greater risk of cerebrovascular disease, especially within the first two months.

Is stroke incidence increased in survivors of adult cancers? A systematic review and meta-analysis

PURPOSE

Existing research hints that people living with and beyond cancer are at an increased risk of stroke. However, there is insufficient evidence to appropriately inform guidelines for specific stroke prevention or management for cancer patients. We conducted a systematic review and meta-analysis to describe and quantify stroke incidence in people living with and beyond cancer.

METHODS

Medline, CINAHL, and EMBASE were searched for epidemiological studies comparing stroke incidence between cancer and non-cancer patients. Reviewers independently extracted data; random-effects meta-analyses and quality assessment were performed.

RESULTS

Thirty-six studies were narratively synthesised. Meta-analysis was conducted using seven studies. Methodological quality was high for most studies. Study populations were heterogeneous, and the length of follow-up and risk factors varied. There was a variation in risk between different cancer types and according to stroke type: pancreatic (HR 2.85 (95% CI 2.43-3.36), ischaemic) (HR 2.28 (95% CI 1.43-3.63), haemorrhagic); lung (HR 2.33 (95% CI 1.63-3.35), ischaemic) (HR 2.14 (95% CI 1.45-3.15), haemorrhagic); and head and neck (HR 1.54 (95% CI 1.40-1.69), haemorrhagic) cancers were associated with significantly increased incidence of stroke. Risk is highest within the first 6 months of diagnosis. Narrative synthesis indicated that several studies also showed significantly increased incidence of stroke in individuals with colorectal cancer, breast cancer, ovarian cancer, nasopharyngeal cancer, leukaemia, and myeloma, and those who have received radiotherapy for head and neck cancers and platinum-based chemotherapy may also have higher stroke incidence.

CONCLUSIONS

Stroke incidence is significantly increased after diagnosis of certain cancers.

IMPLICATIONS FOR CANCER SURVIVORS

Cardiovascular risk should be assessed during cancer survivorship care, with attention to modifying shared cancer/cardiovascular risk factors.

Is radiation-induced arteriopathy in long-term breast cancer survivors an underdiagnosed situation?: Critical and pragmatic review of available literature

PURPOSE

Although considered exceptional, radiation-induced arteriopathy in long-term breast cancer survivors involves three main arterial domains in the irradiated volume, namely axillary-subclavian, coronary, and carotid. Stenosis of medium-large arteries is caused by "accelerated" atherosclerosis, particularly beyond 10 years after long-forgotten radiotherapy. The present review aims at summarizing what is known about arteriopathy, as well as the state of the art in terms of diagnosis and therapeutic management.

DIAGNOSIS

Pauci-symptomatic over years, the usual clinical presentation of arteriopathy involves arm pain with coldness due to subacute or critical ischemia (arterial occlusion), wrongly attributed to an exclusive neurological disorder, and more rarely transient ischemic accident or angina. Evaluation of the supra-aortic trunks by computed tomography and/or magnetic resonance angiography visualizes artery lesions, while Doppler ultrasonography in expert hands assesses diagnosis and downstream functional impact. In severe cases, more invasive angiography directly visualizes long irregular arterial stenosis (full-field radiotherapy), allowing accurate prognosis and treatment.

MANAGEMENT

Requires early diagnosis to enable initiation of medical treatment that increases blood flow (aspirin) as soon as moderate stenosis is detected, combined with correction of vascular risk factors. In intermediate cases, these therapeutic measures are completed by revascularization strategies using transluminal angioplasty-stenting (wall thickness). Antifibrotic treatment is useful in advanced cases with combined radiation injuries.

CONCLUSION

In follow-up of long-term breast cancer survivors with node irradiation, myocardial infarction is treated even if radiotherapy is forgotten, while recognition and diagnosis of chronic arm ischemia due to subclavian artery stenosis needs to be improved for appropriate therapeutic management.

Risk of Stroke in Cancer Survivors: A Meta-analysis of Population-Based Cohort Studies

OBJECTIVE

Accumulating evidence suggests that cancer survivors may have a relatively higher risk of stroke. The aim of this meta-analysis was to determine whether cancer survivors have a relatively higher risk of stroke than cancer-free populations on the basis of published data from population-based cohort studies.

METHODS

PubMed, Embase, and Cochrane Library were searched from inception to February 8, 2020, for population-based cohort studies. Effect estimates with 95% confidence intervals (CIs) were pooled using the random-effects model. We conducted subgroup analyses and meta-regression to explore sources of heterogeneity and the stability of the results.

RESULTS

Twenty population-based cohort studies involving 10,479,530 participants were identified. Overall, the relative risk (RR) for stroke in cancer survivors was 1.66 (95% CI 1.35-2.04; p < 0.001) compared with that in cancer-free controls; survivors of head and neck, hematologic, lung, pancreas, and stomach cancer (all p < 0.05) showed consistently significant results, whereas no significant increased risk was observed for patients with other cancer types. The effects were more prominent in cancer survivors with female sex (RR 1.38, 95% CI 1.18-1.61; p < 0.001), younger age at cancer diagnosis (<45 years) (RR 2.57, 95% CI 1.27-5.19; p = 0.009), and shorter cancer survival duration (≥1-2 years) (RR 1.69, 95% CI 1.18-2.42; p = 0.004). Moreover, cancer survivors had a significantly increased risk of ischemic stroke (RR 1.53, 95% CI 1.28-1.84; p < 0.001) compared with hemorrhagic stroke.

CONCLUSIONS

Cancer plays a critical role in the etiologic of stroke. Due to the existence of substantial heterogeneity among the included studies, the results should be interpreted with caution. However, early prevention and effective intervention of stroke in cancer survivors require attention from health policy makers.

Long-term effects of adjuvant treatment for breast cancer on carotid plaques and brain perfusion

Purpose

Breast cancer treatment has been associated with vascular pathology. It is unclear if such treatment is also associated with long-term cerebrovascular changes. We studied the association between radiotherapy and chemotherapy with carotid pathology and brain perfusion in breast cancer survivors.

Methods

We included 173 breast cancer survivors exposed to radiotherapy and chemotherapy, assessed ± 21.2 years after cancer diagnosis, and 346 age-matched cancer-free women (1:2) selected from the population-based Rotterdam Study. Outcome measures were carotid plaque score, intima-media thickness (IMT), total cerebral blood flow (tCBF), and brain perfusion. Additionally, we investigated the association between inclusion of the carotid artery in the radiation field (no/small/large part), tumor location, and these outcome measures within cancer survivors.

Results

Cancer survivors had lower tCBF (− 19.6 ml/min, 95%CI − 37.3;− 1.9) and brain perfusion (− 2.5 ml/min per 100 ml, 95%CI − 4.3;− 0.7) than cancer-free women. No statistically significant group differences were observed regarding plaque score or IMT. Among cancer survivors, a large versus a small part of the carotid artery in the radiation field was associated with a higher IMT (0.05, 95%CI0.01;0.09). Also, survivors with a right-sided tumor had lower left carotid plaque score (− 0.31, 95%CI − 0.60;− 0.02) and higher brain perfusion (3.5 ml/min per 100 ml, 95%CI 0.7;6.2) than those with a left-sided tumor.

Conclusions

On average two decades post-diagnosis, breast cancer survivors had lower tCBF and brain perfusion than cancer-free women. Also, survivors with a larger area of the carotid artery within the radiation field had a larger IMT. Future studies should confirm if these cerebrovascular changes underlie the frequently observed cognitive problems in cancer survivors.

Chemotherapy-induced brain changes in breast cancer survivors: evaluation with multimodality magnetic resonance imaging

Chemotherapy related cognitive impairments are common in breast cancer patients undergoing chemotherapy. These cognitive dysfunctions are mainly attributable to chemotherapy related brain structural and functional alterations. Multimodality magnetic resonance imaging (MRI) can reveal brain gray matter volume loss, white matter microstructural disruption, reduced gray matter density, impaired cerebral blood flow and brain structural and functional connection networks at both local and global levels. This review outlines the potential applications of multimodality MR imaging techniques in chemotherapy induced cognitive deficit in breast cancer survivors and provides future research perspective in this field.

Major Adverse Cardiovascular Events after Treatment in Early-stage Breast Cancer Patients Receiving Hormone Therapy

This nationwide population-based study investigated the differences in the risks of major adverse cardiovascular events (MACEs) among patients with hormone receptor-positive early-stage breast cancer undergoing different combinations of adjuvant treatments in Taiwan. Data from the National Health Insurance Research Database (NHIRD) and Taiwan Cancer Registry (TCR) along with the national mortality data were used. Patients who underwent surgery as the first mode of treatment were divided into four groups based on the subsequent adjuvant therapy received: hormone therapy (H), hormone therapy + chemotherapy (CH), hormone therapy + radiotherapy (RH), and hormone therapy + radiotherapy + chemotherapy (CRH) groups. The risks of fatal and nonfatal MACE among the groups were examined using the inverse probability of treatment weighted hazard ratio (IPTW-HR). Adjuvant treatment, age, tumour size, and comorbidities significantly affected the risks of MACEs among the 19,007 patients analysed. For nonfatal MACEs, the IPTW-HR was significantly lower in the CH group compare to the H group (0.704, 95% confidence interval [CI]: 0.516-0.961). No significant differences in the risks for fatal MACE were observed among the four groups. The IPTW-HRs for haemorrhagic stroke in the CH group was 0.424 (95% CI: 0.188-0.957), for congestive heart failure (CHF) in the RH group was 0.260 (95% CI: 0.088-0.762), and for ischaemic heart disease in the CRH group was 0.544 (95% CI: 0.317-0.934). Increase in the adjuvant modality does not necessarily increase the nonfatal or fatal MACE risks. Cardiac health should be monitored even in patients receiving hormone therapy alone.

Risk of Stroke After Colorectal Surgery for Cancerous Versus Benign Conditions

BACKGROUND

Cancer treatment, specifically surgical intervention, as a possible stroke trigger is understudied.

METHODS

Using the Nationwide Readmissions Database and validated diagnosis and procedure codes, we identified adults with index admissions for colorectal surgery for colorectal adenocarcinoma (Group A) and compared them to admissions for colorectal surgery for benign conditions (Group B) and hepatobiliary or pancreatic surgery for benign conditions (Group C). Within the colorectal cancer cohort, we further identified patients who underwent open versus laparoscopic surgery. The primary outcome was readmission for ischemic or hemorrhagic stroke up to 1 year. Cumulative risk of ischemic stroke was calculated using risk survival statistics, and hazard ratios (HR) were calculated using adjusted Cox regression.

RESULTS

Patients in Group A had higher 3-month readmission rates for ischemic and hemorrhagic strokes than those in Groups B and C. Higher risk of ischemic stroke (HR 1.46, 95% confidence interval [CI] 1.20-1.79) in Group A compared to Group B was eliminated following adjustments for illness severity and vascular risk factors. Comparing types of colorectal surgical intervention for cancer, there was significantly greater risk of ischemic stroke with open versus laparoscopic surgery, despite adjusting for vascular risk factors (HR 1.70, 95% CI 1.15-2.52).

CONCLUSIONS

We found elevated risk of ischemic stroke up to 1 year following open surgery for colorectal adenocarcinoma compared to laparoscopic. More research is necessary to clarify the underlying surgery-related mechanisms that contribute to elevated risk.

The risk of cardiovascular disease following breast cancer by Framingham risk score

OBJECTIVES

This study evaluates the risk of cardiovascular disease (CVD) following breast cancer, accounting for baseline CVD risk.

METHODS

Within the EPIC-NL (Dutch part of the European Prospective Investigation into Nutrition and Cancer) cohort, 1103 women were diagnosed with breast cancer. For every breast cancer patient, 3-4 women without breast cancer (n = 4328) were selected matched for age, year, and time since cohort enrollment. Based on CVD risk factors at cohort enrollment, 10-year risk of CVD was calculated and categorized: low (< 10%), intermediate (10-20%), high (> 20%). Cox proportional hazard models assessed the risk of CVD events (hospitalization or mortality) and CVD mortality of women with versus without breast cancer, adjusted for baseline CVD risk.

RESULTS

After median follow-up of 5 and 6 years, 92 (8.3%) and 325 (7.5%) CVD events occurred in women with and without breast cancer, respectively. In the low CVD risk group, women with breast cancer had 1.44 (95% CI 1.00-2.06) times higher risk of CVD events than women without breast cancer. In the intermediate and high CVD risk categories, risk of CVD events was similar in women with and without breast cancer. Overall, women with breast cancer had 1.77 (95% CI 1.10-2.86) times higher risk of CVD mortality than women without breast cancer.

CONCLUSIONS

Among women with low CVD risk, women with breast cancer have a higher risk of CVD event than women without breast cancer. Overall, women with breast cancer have a higher risk of CVD mortality than women without breast cancer.

Tamoxifen Use Correlates with Increased Risk of the First Episode of Ischemic Cerebrovascular Disease in Older Women with Breast Cancer: A Case-Control Study in Taiwan

Background and Objectives: There are inconsistent results about the association between ischemic cerebrovascular disease and tamoxifen use in women with breast cancer. The study aimed to evaluate the association between the risk of ischemic cerebrovascular disease and tamoxifen use in older women with breast cancer in Taiwan.

Methods: We designed a retrospective, nationwide, case-control study using the database of the Taiwan National Health Insurance Program. A total of 800 female subjects with breast cancer aged ≥65 years with the first episode of ischemic cerebrovascular disease from 2000 to 2011 were identified as the cases. Additionally, 2,876 female subjects with breast cancer aged ≥65 years without any type of cerebrovascular diseases were selected as the control subjects. The cases and the control subjects were matched with age and comorbidities. Ever use of tamoxifen was defined as a subject who had at least a prescription for tamoxifen before the index date. Never use of tamoxifen was defined as a subject who never had a prescription for tamoxifen before the index date. We used the multivariable logistic regression model to calculate the odds ratio (OR) and 95% confidence interval (CI) for ischemic cerebrovascular disease associated with tamoxifen use.

Results: After adjusting for confounding variables, the adjusted OR of ischemic cerebrovascular disease was 2.5 for subjects with ever use of tamoxifen (95% CI 2.10, 2.97), compared with never use of tamoxifen. In addition, the adjusted OR of ischemic cerebrovascular disease was 1.15 (95% CI 1.10, 1.21) in subjects with ever use of tamoxifen as increase in use duration per 1 year. The adjusted OR of ischemic cerebrovascular disease was 2.54 (95% CI 2.03, 3.17) in subjects with ever use of tamoxifen as increase in dosage per 1 mg.

Conclusions: Tamoxifen use is significantly associated with 2.5-fold increased odds of ischemic cerebrovascular disease among older women with breast cancer in Taiwan. There are duration-dependent and dose-dependent effects of tamoxifen use on the risk of ischemic cerebrovascular disease.

Vascular function in breast cancer survivors on aromatase inhibitors: a pilot study

PURPOSE

Aromatase inhibitors (AI) have been shown to reduce breast cancer-related mortality in women with estrogen positive (ER+) breast cancer. The use of AIs, however, has been associated with higher rates of hypertension, hyperlipidemia, and cardiovascular (CV) events.

METHODS

A cross-sectional study of 25 healthy postmenopausal women and 36 women with curative intent breast cancer on an AI was performed to assess endothelial dysfunction, an indicator of risk for CV events. Consented subjects underwent vascular testing using the HDI/Pulse Wave CR-2000 Cardiovascular Profiling System and the EndoPAT2000 system.

RESULTS

Mean age was 61.7 and 59.6 years (cases, controls). Most subjects were Caucasian and overweight. Controls had a lower mean systolic blood pressure (128.6 mmHg vs. 116.2 mmHg, p = 0.004). Median estradiol levels were reduced in cases (2 vs. 15 pg/ml, p < 0.0001). EndoPAT ratio (0.8 vs. 2.7, p < 0.0001) was significantly reduced in cases as compared to controls. Median large artery elasticity (12.9 vs. 14.6 ml/mmHg × 10, p = 0.12) and small artery elasticity (5.2 vs. 7.0 ml/mmHg × 100, p = 0.07) were also reduced though not statistically significant. There was no correlation between use of chemotherapy, radiation therapy, type of AI, or duration of AI use and endothelial function. When adjusting for differences in blood pressure, results remained significant.

CONCLUSION

Breast cancer cases on AIs have reductions in endothelial function, a predictor of adverse CV disease.

IMPACT

Vascular function changes in breast cancer cases on AIs compared to postmenopausal women. Further work is needed to evaluate vascular changes over time.

Symptomatic Atherosclerotic Disease and Decreased Risk of Cancer-Specific Mortality: A Prospective, Population-Based Study (NEDICES)

The few studies that have assessed the association between symptomatic atherosclerotic disease and risk of cancer have had conflicting results. In addition, these studies ascertained participants either from treatment settings (ie, service-based studies) or by using a records linkage system (ie, medical records of patients evaluated at clinics or hospitals) and, therefore, were prone to selection bias. Our purpose was to estimate the risk of cancer mortality in a large population-based sample of elderly people, comparing participants with symptomatic atherosclerotic disease (atherosclerotic stroke and coronary disease) to their counterparts without symptomatic atherosclerotic disease (ie, controls) in the same population.In this population-based, prospective study (Neurological Disorders of Central Spain, NEDICES), 5262 elderly community-dwelling participants with and without symptomatic atherosclerotic disease were identified and followed for a median of 12.1 years, after which the death certificates of those who died were reviewed.A total of 2701 (53.3%) of 5262 participants died, including 314 (68.6%) of 458 participants with symptomatic atherosclerotic disease and 2387 (49.7%) of 4804 controls. Cancer mortality was reported significantly less often in those with symptomatic atherosclerotic disease (15.6%) than in controls (25.6%) (P < 0.001). In an unadjusted Cox model, risk of cancer-specific mortality was decreased in participants with symptomatic atherosclerotic disease (HR = 0.74, 95% confidence interval [CI], 0.55-0.98, P = 0.04) vs. those without symptomatic atherosclerotic disease (reference group). In an adjusted Cox model, HR = 0.58; 95% CI, 0.38-0.89; P = 0.01.This population-based, prospective study suggests that there is an inverse association between symptomatic atherosclerotic disease and risk of cancer mortality.

Prevalence of Cerebral Small-Vessel Disease in Long-Term Breast Cancer Survivors Exposed to Both Adjuvant Radiotherapy and Chemotherapy

Purpose

Adjuvant radiotherapy and chemotherapy for breast cancer have been related to transient ischemic attacks and stroke. To date, no studies have investigated the relationship between these adjuvant therapies and subclinical cerebral small-vessel disease in survivors of breast cancer. We compared white matter lesion (WML) volume and prevalence of brain infarctions and cerebral microbleeds (CMBs) between breast cancer survivors exposed to adjuvant radiotherapy and chemotherapy (aRCeBCSs) for primary disease and a population-based reference group.

Patients and Methods

Multimodal magnetic resonance imaging (1.5 T) was performed in 187 aRCeBCSs who received primary breast cancer treatment on average more than 20 years before this study and 374 age-matched reference women without a history of cancer. WML volume was segmented using fully automated software. Experienced raters reviewed all scans for cortical infarctions, lacunar infarctions, strictly lobar CMBs, and deep/infratentorial CMBs with or without lobar CMBs. Within the aRCeBCS group, we also analyzed the association between relative radiotherapy exposure to the carotid artery and prevalence of WML volume and CMBs.

Results

The aRCeBCS group had a higher prevalence of both total CMBs and CMBs in a deep/infratentorial region than the reference group. No between-group differences were observed in the prevalence of infarctions or WML volume. Exposure of the carotid artery to radiation was not associated with WML volume or CMBs.

Conclusion

More CMBs were found in the aRCeBCS group than in the population-based controls. These vascular lesions potentially mark cerebrovascular frailty that could partially explain the well-documented association between chemotherapy and cognitive dysfunction. No support was found for a radiotherapy-related origin of CMBs.

Carotid dosimetry for T1 glottic cancer radiotherapy

OBJECTIVE

Radiotherapy for T1 glottic cancer is commonly delivered using a lateral parallel opposed pair of megavoltage photon fields. There is increasing reported evidence of cerebrovascular events due to radiation-induced carotid stenosis. An alternative field arrangement is to use an anterior oblique technique. This study compares the carotid dosimetry between the two techniques and reviews the evidence for the risk of radiation-induced vascular events.

METHODS

The radiotherapy plans of 10 patients with T1 glottic cancer treated with an anterior oblique technique were examined for carotid dose. Alternative plans were then created using a parallel opposed pair of fields and the dose to the carotids compared. All patients received 50 Gy in 16 fractions treating once daily, for 5 days in a week.

RESULTS

The average of the mean dose to the carotids with the anterior oblique technique was 21 Gy compared with 37 Gy using the lateral parallel opposed pair arrangement (p < 0.0001).

CONCLUSION

An anterior oblique field arrangement for the treatment of T1 glottic cancer results in a significantly lower radiation dose to the carotid arteries, which may be clinically important in terms of reducing the risk of cerebrovascular events in long-term survivors.

ADVANCES IN KNOWLEDGE

Although the anterior oblique technique for treating early glottic cancers is well described, and it is predictable that the dose received by the carotid arteries should be lower with this technique, to our knowledge this is the first study to quantify that reduction in dose with a series of patients.

Radiation-induced carotid artery atherosclerosis

PURPOSE

Carotid arteries frequently receive significant doses of radiation as collateral structures in the treatment of malignant diseases. Vascular injury following treatment may result in carotid artery stenosis (CAS) and increased risk of stroke and transient ischaemic attack (TIA). This systematic review examines the effect of radiotherapy (RT) on the carotid arteries, looking at the incidence of stroke in patients receiving neck radiotherapy. In addition, we consider possible surrogate endpoints such as CAS and carotid intima-medial thickness (CIMT) and summarise the evidence for radiation-induced carotid atherosclerosis.

MATERIALS AND METHODS

From 853 references, 34 articles met the criteria for inclusion in this systematic review. These papers described 9 studies investigating the incidence of stroke/TIA in irradiated patients, 11 looking at CAS, and 14 examining CIMT.

RESULTS

The majority of studies utilised suboptimally-matched controls for each endpoint. The relative risk of stroke in irradiated patients ranged from 1.12 in patients with breast cancer to 5.6 in patients treated for head and neck cancer. The prevalence of CAS was increased by 16-55%, with the more modest increase seen in a study using matched controls. CIMT was increased in irradiated carotid arteries by 18-40%. Only two matched-control studies demonstrated a significant increase in CIMT of 36% and 22% (p=0.003 and <0.001, respectively). Early prospective data demonstrated a significant increase in CIMT in irradiated arteries at 1 and 2 years after RT (p<0.001 and <0.01, respectively).

CONCLUSIONS

The incidence of stroke was significantly increased in patients receiving RT to the neck. There was a consistent difference in CAS and CIMT between irradiated and unirradiated carotid arteries. Future studies should optimise control groups.

Global and focal white matter integrity in breast cancer survivors 20 years after adjuvant chemotherapy

OBJECTIVES

To date, only four small studies have investigated the effects of adjuvant chemotherapy for breast cancer on the microstructure of cerebral white matter with magnetic resonance imaging (MRI). These studies, which were conducted shortly up to 10 years post-treatment, showed that chemotherapy is associated with focal loss of microstructural white matter integrity. We investigated the long-term effect of chemotherapy on white matter microstructural integrity by comparing the brains of chemotherapy-exposed breast cancer survivors to those of a population-based sample of women without a history of cancer.

EXPERIMENTAL DESIGN

Diffusion tensor imaging (DTI) MRI (1.5 T) was performed in 187 CMF (cyclophosphamide, methotrexate, and 5-flourouracil) chemotherapy-exposed breast cancer survivors, mean age 64.2 (sd = 6.5) years, who had been diagnosed with cancer on average 21.2 (sd = 4.4) years before, and 374 age-matched cancer-free reference subjects from a population-based cohort study. Outcome measures were whole-brain microstructural integrity as measured by fractional anisotropy and mean/axial/radial diffusivity and focal white matter integrity, which was analyzed with tract-based spatial statistics. All analyses were adjusted for age, cardiovascular risk factors, education, and symptoms of depression.

PRINCIPAL OBSERVATIONS

No significant group differences were observed in white matter integrity. However, within the breast cancer survivors, time since treatment was inversely associated with lower global and focal white matter integrity.

CONCLUSIONS

This cross-sectional study suggests that among chemotherapy-exposed breast cancer survivors white matter microstructural integrity deteriorates with accumulating time since treatment. This warrants further investigation.

Vascular injury in cancer survivors

With an increase in the number of patients surviving many years following successful cancer treatment, has come an improved understanding of the long-term effects of cancer therapy and its implications on future health. Premature cardiovascular disease is a significant cause of early morbidity and the leading non-cancer cause of death in this population. Chemotherapeutic agents and radiation therapy are known to be cardiotoxic. However, numerous vascular-related toxicities have also been observed among cancer survivors, such as myocardial ischemia, transient ischemic attacks, and stroke, suggesting a degree of chronic endothelial injury and dysfunction leading to premature atherosclerotic disease. Vascular health in cancer survivors may be further compromised by metabolic abnormalities such as obesity, insulin resistance, and dyslipidemias which have also been reported following cancer therapy. Furthermore, some survivors experience gonadal dysfunction and loss of potentially protective sex steroids or undergo hormonal therapies that induce additional metabolic abnormalities. The effects of cancer therapies upon the endothelial monolayer have not been fully explored. An understanding of potential injury to and dysfunction of the circulatory system among cancer survivors is essential for identifying preventive strategies and therapeutic targets.

Long-term safety of radiotherapy and breast cancer laterality in older survivors

BACKGROUND

Although adjuvant radiotherapy (RT) following surgery for breast cancer improves overall survival, controversy exists about its long-term adverse impact on cardiovascular health in older survivors.

AIM

To determine whether incident cardiovascular disease (CVD) is associated with RT and whether tumor laterality modifies this association.

METHODS

Women aged 65+ years diagnosed with stage I and II breast cancer between 1990 and 1994 were identified from three health plans. Women were followed through CVD outcomes, health plan disenrollment, death, or study end (December 31, 2004). The main independent variable was RT use. Adjusted HRs and 95% CIs were estimated using Cox proportional hazards models with time-dependent tamoxifen and RT use status. We adjusted for age, race, stage, estrogen receptor/progesterone receptor, hypertension, and diabetes.

RESULTS

In the full cohort (N = 806), RT was not associated with greater risk of CVD (maximum follow-up was 14 years). However, within the RT-exposed group (N = 340), women treated for left-side breast cancer had a significant increased risk of CVD outcomes (HR = 1.53, 95% CI: 1.06-2.21) compared with women with right-sided tumors.

CONCLUSION

Laterality is critical to understanding the effect of RT on CVD. Studies of more contemporary cohorts of women treated with RT should incorporate this variable to determine whether the risk persists with refinements in the dosing and delivery of RT.

IMPACT

As some irradiation to the heart is unavoidable even with refined modern RT techniques, continued effort is required to minimize such exposures, especially in older women with left-sided tumors.

Ischemic stroke and transient ischemic attack after head and neck radiotherapy: a review

BACKGROUND AND PURPOSE

Cerebrovascular disease can complicate head and neck radiotherapy and result in transient ischemic attack and ischemic stroke. Although the incidence of radiation vasculopathy is predicted to rise with improvements in median cancer survival, the pathogenesis, natural history, and management of the disease are ill defined.

METHODS

We examined studies on the epidemiology, imaging, pathogenesis, and management of medium- and large-artery intra- and extra-cranial disease after head and neck radiotherapy. Controlled prospective trials and larger retrospective trials from the last 30 years were prioritized.

RESULTS

The relative risk of transient ischemic attack or ischemic stroke is at least doubled by head and neck radiotherapy. Chronic radiation vasculopathy affecting medium and large intra- and extra-cranial arteries is characterized by increasing rates of hemodynamically significant stenosis with time from radiotherapy. Disease expression is the likely consequence of the combined radiation insult to the intima-media (accelerating atherosclerosis) and to the adventitia (injuring the vasa vasorum). Optimal medical treatment is not established. Carotid endarterectomy is confounded by the need to operate across scarred tissue planes, whereas carotid stenting procedures have resulted in high restenosis rates.

CONCLUSIONS

Head and neck radiotherapy significantly increases the risk of transient ischemic attack and ischemic stroke. Evidence-based guidelines for the management of asymptomatic and symptomatic (medium- and large-artery) radiation vasculopathy are lacking. Long-term prospective studies remain a priority, as the incidence of the problem is anticipated to rise with improvements in postradiotherapy patient survival.

Cardiorespiratory fitness and quality-of-life analysis posttreatment in breast cancer survivors

This study compared VO(2peak), treatment frequency and dosage, and QOL between 22 post-treated breast cancer survivors (CATotal) and 22 apparently healthy, age-matched women (CO). The CATotal group included 11 with no history of any other co-morbidities (CA) and 11 with controlled hypertension (CA + H). VO(2peak) was measured using the Bruce Protocol. QOL was measured using the SF-36 survey. Significant differences were observed in VO(2peak) between CATotal and CO (p = 0.014), CA and CA + H (p = 0.001), and CA + H and CO (p = 0.001). Physical, emotional, and mental health domains of the SF-36 were significantly different between CATotal and CO (p = 0.006, 0.001, and 0.05 respectively). These results suggest that breast cancer survivors with controlled hypertension can experience a significant reduction in VO(2peak) when compared to apparently healthy, age-matched controls. Also, treatment frequency and dosage affected QOL in this group of survivors.

Radiation to supraclavicular and internal mammary lymph nodes in breast cancer increases the risk of stroke

The aim of this study was to assess whether adjuvant treatment of breast cancer (BC) affects the risk of stroke, and to explore radiation targets and fraction doses regarding risk and location of stroke. In a Swedish BC cohort diagnosed during 1970-2003, we carried out a nested case-control study of stroke after BC, with relevant details extracted from medical records. The odds ratio (OR) for radiotherapy (RT) vs that of no RT did not differ between cases and controls (OR=0.85; confidence interval, CI=0.6-1.3). Radiotherapy to internal mammary chain (IMC) and supraclavicular (SCL) lymph nodes vs that of no RT was associated with a higher, although not statistically significant, risk of stroke (OR=1.3; CI=0.8-2.2). In a pooled analysis, RT to IMC and SCL vs the pooled group of no RT and RT to breast/chest wall/axilla (but not IMC and SCL), showed a significant increase of stroke (OR=1.8; CI=1.1-2.8). There were no associations between cancer laterality, targets of RT, and location of stroke. The radiation targets, IMC and SCL, showed a statistically significant trend for an increased risk of stroke with daily fraction dose. Our finding of a target-specific increased risk of stroke and a dose-response relationship for daily fraction dose, indicate that there may be a causal link between RT to the IMC and SCL and risk of stroke.

Cerebrovascular disease risk in older head and neck cancer patients after radiotherapy

PURPOSE

Cerebrovascular disease is common in head and neck cancer patients, but it is unknown whether radiotherapy increases the cerebrovascular disease risk in this population.

PATIENTS AND METHODS

We identified 6,862 patients (age > 65 years) from the Surveillance, Epidemiology, and End Results (SEER) -Medicare cohort diagnosed with nonmetastatic head and neck cancer between 1992 and 2002. Using proportional hazards regression, we compared risk of cerebrovascular events (stroke, carotid revascularization, or stroke death) after treatment with radiotherapy alone, surgery plus radiotherapy, or surgery alone. To further validate whether treatment groups had equivalent baseline risk of vascular disease, we compared the risks of developing a control diagnosis, cardiac events (myocardial infarction, percutaneous coronary intervention, coronary artery bypass graft, or cardiac death). Unlike cerebrovascular risk, no difference in cardiac risk was hypothesized.

RESULTS

Mean age was 76 +/- 7 years. Ten-year incidence of cerebrovascular events was 34% in patients treated with radiotherapy alone compared with 25% in patients treated with surgery plus radiotherapy and 26% in patients treated with surgery alone (P < .001). After adjusting for covariates, patients treated with radiotherapy alone had increased cerebrovascular risk compared with surgery plus radiotherapy (hazard ratio [HR] = 1.42; 95% CI, 1.14 to 1.77) and surgery alone (HR = 1.50; 95% CI, 1.18 to 1.90). However, no difference was found for surgery plus radiotherapy versus surgery alone (P = .60). As expected, patients treated with radiotherapy alone had no increased cardiac risk compared with the other treatment groups (P = .63 and P = .81).

CONCLUSION

Definitive radiotherapy for head and neck cancer, but not postoperative radiotherapy, was associated with excess cerebrovascular disease risk in older patients.

Management of stroke in cancer

Cerebrovascular disorders, including brain infarction, brain hemorrhage, and cerebral venous thrombosis, can occur as an early sign of cancer, but typically occur late in the clinical course. These disorders are due to a variety of pathogenic mechanisms, including coagulation disorders associated with the cancer, invasion or compression of vessels from tumor in or adjacent to the brain, and the adverse effects of cancer therapy. The appropriate therapy for these cerebrovascular disorders is empiric in most instances, because as yet there are no prospective treatment trials for them. A review of the existing literature reveals that improvement in patient quality of life and prevention of further cerebrovascular events can be obtained in some clinical situations.

Prospective analysis of carotid artery flow in breast cancer patients treated with supraclavicular irradiation 8 or more years previously: no increase in ipsilateral carotid stenosis after radiation noted

BACKGROUND

To the authors' knowledge, the effects of supraclavicular fossa radiation on the carotid artery are not well described. In the current study, the authors performed a prospective study to examine the long-term risk of carotid artery stenosis after supraclavicular irradiation for breast cancer.

METHODS

A total of 46 breast cancer patients who were treated with adjuvant radiation to the supraclavicular fossa with >8 years of follow-up underwent bilateral Doppler imaging of the carotid artery. Two independent cardiologists interpreted each ultrasound study with no knowledge of which side was treated.

RESULTS

The median follow-up from the date of diagnosis was 14.6 years and the mean patient age at the time of ultrasound was 55 years. The median prescribed dose to the supraclavicular fossa was 50 grays. Four patients were found to have clinically relevant, asymptomatic carotid stenosis, for which a cardiology referral was necessary. Only 1 of these 4 patients had stenosis involving the irradiated carotid artery only; 1 patient had bilateral stenosis and 2 patients had only contralateral stenosis. There was no difference noted with regard to isolated ipsilateral versus contralateral medial intimal thickening of the carotid artery (5 patients vs 6 patients, respectively). Furthermore, there were no differences noted with regard to ipsilateral versus contralateral peak systolic flow in the internal (83.5 vs 85.6 cm/seconds; P= .522 by the Student t test and P= .871 by the signed rank test) or common (74.4 vs 77.0 cm/seconds; P= .462 by the Student t test and P= .246 by the signed rank test) carotid artery.

CONCLUSIONS

In this prospective study of breast cancer patients with long follow-up, there was no evidence of late, clinically relevant stenosis, increased intimal thickening, or increased peak systolic carotid artery flow secondary to supraclavicular irradiation.

Cardiovascular effects of breast cancer radiotherapy

Cardiac toxicity has been implicated as the primary reason for excess non-breast cancer mortality in early breast cancer radiotherapy studies. Refinements in radiotherapy techniques have allowed for a considerable reduction of this risk in the majority of breast cancer patients. Recent large population-based studies confirmed an increase of cardiovascular death risk in patients irradiated for cancer of the left breast and in individuals exposed to relatively low (hitherto believed to be of no cardiovascular disease risk) doses of radiation, such as atomic bomb survivors or patients treated for various benign conditions. The issue of potential radiation-related cardiac damage may also be assuming a new significance due to the widespread use of other cardiotoxic agents, such as anthracyclines, paclitaxel and trastuzumab. The aim of this review is to summarize and critically analyze the available evidence on the impact of ionizing radiation on the cardiovascular system, with special attention to recent data demonstrating previously unrecognized adverse effects. This review discusses the pathology of radiation-related cardiovascular disease, its clinical presentation, risk factors and methods of assessment, as well as technical developments minimizing cardiac exposure. Epidemiological data are presented on the incidence of radiation-induced heart disease and cardiovascular mortality in various populations of patients irradiated for breast cancer and in individuals exposed to low radiation doses. Additionally, non-cardiac radiation-related vascular morbidity and mortality in breast cancer patients are addressed.