
==== Front
Rev Assoc Med Bras (1992)
Rev Assoc Med Bras (1992)
ramb
Revista da Associação Médica Brasileira
0104-4230
1806-9282
Associação Médica Brasileira

39292089
00607
10.1590/1806-9282.20240517
Original Article
The effects of trastuzumab therapy on endothelial functions of breast cancer patients
https://orcid.org/0000-0001-5984-1857
Alp Çağlar Conceptualization Data curation Formal Analysis Writing – original draft Writing – review & editing 1 *
https://orcid.org/0000-0001-8505-489X
Doğru Mehmet Tolga Conceptualization Formal Analysis Writing – original draft Writing – review & editing 1
https://orcid.org/0000-0003-1970-2849
Yalçın Selim Conceptualization Writing – original draft Writing – review & editing 2
https://orcid.org/0000-0002-0792-7103
Karal Ali Oğuzhan Data curation Writing – review & editing 1
1 Kırıkkale University, Faculty of Medicine, Department of Cardiology – Kırıkkale, Turkey.
2 Kırıkkale University, Faculty of Medicine, Department of Oncology – Kırıkkale, Turkey.
*Corresponding author: drcaglaralp@gmail.com
Conflicts of interest: the authors declare there is no conflicts of interest.

16 9 2024
2024
70 9 e2024051708 6 2024
13 6 2024
https://creativecommons.org/licenses/by/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
SUMMARY

OBJECTIVE:

Breast cancer is among the highest causes of morbidity and mortality in women. Trastuzumab therapy, which is known to be significantly cardiotoxic, is mainly used to treat patients with resistant breast cancer, including estrogen receptor-positive type. We aimed to show the effects of trastuzumab therapy on endothelial functions of breast cancer patients.

METHODS:

In this study, a total of 26 participants (24 female and 2 male patients, minimum age: 38 years, maximum age: 79 years, and mean age 57.3±12.7 years) were enrolled in the study. For the statistical evaluation of data, we classified the participants of the study as follows: Pretreatment: Before trastuzumab therapy; Treatment Period 1: 1 month after the first dose of trastuzumab; Treatment Period 2: 4 months after the first dose of trastuzumab; Treatment Period 3: 12 months after the first dose of trastuzumab. We conducted repeated-measures analysis of variance (Greenhouse-Geisser) and paired-sample t-tests to statistically compare the groups using flow-mediated dilation measurements.

RESULTS:

We determined that there are statistically significant differences between flow-mediated hyperemia and ratio values (flow-mediated dilation) of the groups (p<0.009 and p<0.001, respectively).

CONCLUSION:

Our data indicate that trastuzumab therapy could have negative effects on endothelial functions in breast cancer patients.

KEYWORDS:

Breast cancer
Trastuzumab
Cardiovascular system
Autonomic nervous system
==== Body
pmcINTRODUCTION

Considering that breast cancer is the most common type of cancer in women and causes serious clinical problems and complications, knowledge about the side effects of many forms of treatment and drugs developed for breast cancer becomes increasingly important in clinical practice 1 . Trastuzumab is a treatment agent that has achieved significant success in the treatment of breast cancer, especially in groups with positive estrogen receptors 2 .

It is a well-known fact that trastuzumab therapy has critical usefulness in the treatment of breast cancer. On the contrary, this therapy has potentially significant side effects and serious complications, especially on the cardiovascular system, which are of great clinical importance and require a more stringent monitoring of cardiovascular system complications in patients under trastuzumab treatment.

The presence of anthracyclines in the treatment protocols applied to many patients receiving trastuzumab increases the frequency and severity of possible cardiac complications. However, this sometimes causes controversy about to what extent trastuzumab and anthracyclines are responsible for such cardiac complications 2-9 .

Nevertheless, regardless of its evaluation method, the cardiotoxicity of trastuzumab is evident in many studies and is of great importance in the clinical follow-up 4,5 . Congestive heart failure (CHF) is the most common outcome observed when trastuzumab therapy is given alone or in combination with anthracyclines in particular. In view of all possible etiological factors, endothelial dysfunction constitutes one of the most important pathophysiological mechanisms underlying many pathological clinical conditions that cause CHF 10-14 , so it could be considered that endothelial dysfunction might have a critical role in the pathophysiological mechanism for trastuzumab-mediated CHF (TMCHF) 12-14 .

Flow-mediated dilation (FMD) is the most commonly used method for noninvasive assessment of endothelial functions 15-18 . Endothelial functions can be affected by a variety of chronic degenerative diseases, including atherosclerosis, diabetes mellitus (DM), and hypertension 17 . Accordingly, FMD can be useful in the evaluation of nitric oxide (NO)-releasing capacity in breast cancer patients on trastuzumab therapy 15-18 .

There is a few number of data about endothelial dysfunction associated with trastuzumab therapy in breast cancer patients in the literature. In this study, we aimed to show the negative effects of trastuzumab therapy on endothelial functions of breast cancer patients.

METHODS

This is a cross-sectional study of 55 patients with HER-2-positive breast cancer admitted to the Oncology Department of the Medical School of Kırıkkale University, and the relevant symptoms were screened between October 2022 and October 2023. The study design was approved by the local ethics committee (ID 07/01 12.09.2022).

After the objectives of the study were described to the patients and their written informed consents were obtained, baseline characteristics and clinical data of the participants were collected by an interview and recorded in the study questionnaire and data from FMD analysis.

Patients

All participants were evaluated in Oncology and Cardiology clinics. Cardiologic evaluation and measurements, including FMD measurements, were performed by a cardiologist.

Patient selection

Exclusion criteria were stable or unstable angina pectoris, acute myocardial infarction, systolic heart failure (ejection fraction (EF)<50%), hypertension, valvular heart disease, aortic aneurysm, acute or chronic renal failure (serum creatinine level >1.5 mg/dL), DM, asthma or chronic obstructive lung disease, neurological and psychiatric diseases, and alcohol and drug abusement.

A total of 29 patients were excluded because of developing a condition included in the exclusion criteria during the study period.

A total of 26 participants (24 female and 2 male patients, minimum age: 38 years, maximum age: 79 years, and mean age: 57.3±12.7 years) were enrolled in the study.

We classified the study participants as follows:

Group 1: Pretreatment: Before trastuzumab therapy

Group 2: (Treatment Period 1) 1 month after the first dose of trastuzumab

Group 3: (Treatment Period 2) 4 months after the first dose of trastuzumab

Group 4: (Treatment Period 3) 12 months after the first dose of trastuzumab.

Oncologic evaluation

A total of 26 patients evaluated for the study were early-stage HER-2-positive [3 positive by immunohistochemistry or positive by fluorescence in situ hybridization (FISH) technique] and completed their local treatment (modified radical mastectomy and axillary dissection) with at least four courses of adjuvant anthracycline-based chemotherapy followed by trastuzumab (the first dose 8 mg/kg, after that, maintenance dose 6 mg/kg) every 3 weeks) intravenous treatment for 1 year was planned.

All patients had completed adjuvant radiotherapy, during which they received 2 Gy/fraction/day, a total of 40–60 Gy (mean 52 Gy) of radiotherapy.

Cardiologic evaluation

Following a detailed medical history taking, all subjects were physically examined and their blood pressures were measured in both arms using a sphygmomanometer. 12-channel electrocardiography (ECG) recordings and transthoracic echocardiography (Ge-Vivid 7 Pro, General Electric; FL, USA,), FMD, and PWA tests were performed.

Flow-mediated dilation

A Ge-Vivid 7 Pro, 12 L Doppler probe (General Electric, Florida, USA) was used to detect the measurements of flow-mediated dilation. Flow-mediated dilation measurements were performed as defined by Hayward et al 18 .

In the present study,

basal brachial artery diameter measurements were represented as FMD basal (cm),

the brachial artery diameter at Hyperemia phase was represented as FMD hyperemia (cm), and

we also calculated the FMD basal/FMD hyperemia ratio (%) 15,17 .

Statistical analysis

All statistical analyses were conducted using SPSS version 20.0 (SPSS; Chicago, IL, USA). According to statistical distribution types, we showed the data as mean±standard deviation (SD) which have normal distribution. Besides, we showed the data as median (25–75%) which have non-normal distribution. Repeated-measures analysis of variance (ANOVA) (Greenhouse-Geisser) and paired sample t-tests were employed to compare data of the groups. A p-value of <0.05 was accepted as statistically significant.

RESULTS

Table 1 shows FMD measures of all participants of the study.

Table 1 Statistical comparison of flow-mediated dilation measurements of breast cancer patients under trastuzumab therapy.

Patient characteristics	Pretreatment	Treatment Period 1	Treatment Period 2	Treatment Period 3	p	
FMD basal (mm)	3.88±0.61	3.82±0.56	3.83±0.53	3.90±0.48	0.139	
FMD hyperemia (mm)	4.21±0.64	4.08±0.57	4.03±0.54	4.04±0.48	0.009	
FMD ratio (%)*	92.10±3.65	93.51±3.34	95.07±3.60	96.60±2.38	<0.001	
Bold values are statistically significant measures.

Repeated-measures ANOVA (Greenhouse-Geisser) test, Mean±SD, p<0.05.

* FMD Ratio: [FMD basal/FMD hyperemia]x100. Pretreatment: Before trastuzumab therapy. Treatment Period 1: 1 month after the first dose of trastuzumab. Treatment Period 2: 4 months after the first dose of trastuzumab. Treatment Period 3: 12 months after the first dose of trastuzumab.

There was no statistically significant difference between the FMD basal diameters of the groups. However, there were statistically significant differences in FMD hyperemia values between the groups (p<0.009) (Table 1). After the Bonferroni adjustment test, we found a significant difference in FMD hyperemia between Group 1 and Group 3 (p=0.027).

Our results have shown that there was a significant decrease in the hyperemia capability of the endothelial layer according to trastuzumab therapy (Figure 1). As FMD ratio values are derivatives of FMD basal and hyperemia, a similar change is seen in FMD ratio values. According to our results, there are significant decreases in FMD ratios during treatment (Table 1). Besides, we identified significant differences in FMD ratios between Group 1 and Group 3 (p=0.001), Group 1 and Group 4 (p<0.001), and Group 2 and Group 3 (p=0.018) (Figure 2).

Figure 1 Variation of flow-mediated diameter hyperemia values with time periods in breast cancer patients treated with trastuzumab.

Figure 2 Variation of flow-mediated diameter ratio values with time periods in breast cancer patients treated with trastuzumab.

DISCUSSION

In this study, decreased FMD hyperemia and increased FMD ratio (basal/hyperemia diameters) values were found during trastuzumab therapy. As the FMD test results showed in our study, progressively increasing endothelial dysfunction is observed in four consecutive evaluations during the 1-year treatment period.

Endothelial cells, which constitute one of the most important cell groups of the entire cardiovascular system, both structurally and functionally, have an indispensable importance in the holistic functioning of the cardiovascular system 19 . Many pathological conditions affecting endothelial cells are known to constitute the basic pathophysiological mechanisms of cardiovascular diseases. However, the factors that negatively affect endothelial cells structurally and functionally also include drugs used to treat various diseases.

The most important of these drug groups are different types of treatment agents used in cancer chemotherapy. The mechanisms by which cancer chemotherapy causes toxic effects on endothelial cells are not fully known. It is common knowledge that the main function of endothelial cells is to dynamically maintain vascular permeability and tone under different biological requirements. Many different mediators are involved in the fulfillment of this function at the tissue and cell level. Among these factors, vascular endothelial growth factor (VEGF) that mobilizes endothelial progenitor cells for vascular repair, IL-6, TNFα, and intercellular adhesion molecule 1, NO, reactive oxygen species (ROS), and platelet activation are the most important ones 20 .

Trastuzumab is one of the most important chemotherapeutic drugs that have structural and functional toxic effects on endothelial cells used in cancer chemotherapy 21 . Many studies have found that cardiotoxicity related to trastuzumab is closely related to age, obesity, hypertension, coronary artery disease, and concomitant anthracycline therapy 6-9 . These factors are also known as endothelial dysfunction.

The toxic effect of trastuzumab, acting by blocking the HER2 signaling pathway, which is of great importance in putting the structurally and functionally normal functions of the cardiovascular system on the route, can also be observed clinically in many patients 10 . The HER2 signaling mechanism is related to NO generation in the endothelial layer 11 .

It has been demonstrated in many different animal experiments that pathological changes in the HER2 signaling pathway cause clinical conditions such as cardiomyopathies and related heart failure 22 . The HER2–HER4 heterodimerization mechanism actually constitutes a protective mechanism against the effects of many external toxic agents in endothelial and cardiac muscle cells. On the contrary, trastuzumab blocks this mechanism and exposes the endothelium, including itself, to the effects of many toxic agents 23 . In many different conditions, the amount of ROS increases in endothelial dysfunction. Meanwhile, angiotensin II (ANG II), thrombin, and nicotinamide adenine dinucleotide phosphate-oxidase (NADPH) with a negative positive feedback mechanism are the most important factors that increase ROS 24 . There are a lot of studies that have shown that the expression of the endothelial nitric oxide synthase (eNOS) gene is important for endothelial functions and simultaneously survival following trastuzumab treatment. Besides, many of the studies have also shown that eNOS gene polymorphisms could cause negative effects on survival in breast cancer patients and the patients with higher expression of eNOS in the microvessels have better prognoses too 25 .

It seems that the alteration of NO production capacity during trastuzumab therapy could be a representative of trastuzumab toxicity. The findings of our study are consistent with previous studies. Evaluations at the end of different periods of trastuzumab therapy indicated progressive endothelial dysfunction, as demonstrated by FMD tests in our study.

CONCLUSION

Our data showed that the patients receiving trastuzumab therapy had deteriorated flow-mediated dilation responses, suggesting endothelial dysfunction caused by this treatment.

STATEMENT OF ETHICS

The study protocol was approved by the Kirikkale Üniversity Ethics Committee, Kirikkale, Turkey (Date/Number: 12.06.2022 07/01).

DATA AVAILABILITY STATEMENT

All data relevant to this study will be provided by the authors upon specific request.

Funding: none.
==== Refs
REFERENCES

1 Gates TJ. Screening for cancer: evaluating the evidence Am Fam Physician 2001 63 3 513 522 11272300
2 Bartsch R Bergen E. ASCO 2018: highlights in HER2-positive metastatic breast cancer Memo 2018 11 4 280 283 10.1007/s12254-018-0441-x 30595754
3 Guo S Wong S. Cardiovascular toxicities from systemic breast cancer therapy Front Oncol 2014 4 346 10.3389/fonc.2014.00346 25538891
4 Denegri A Moccetti T Moccetti M Spallarossa P Brunelli C Ameri P. Cardiac toxicity of trastuzumab in elderly patients with breast cancer J Geriatr Cardiol 2016 13 4 355 363 10.11909/j.issn.1671-5411.2016.04.003 27403145
5 Azambuja E Procter MJ Veldhuisen DJ Agbor-Tarh D Metzger O Filho Steinseifer J Trastuzumab-associated cardiac events at 8 years of median follow-up in the Herceptin Adjuvant trial (BIG 1-01) J Clin Oncol 2014 32 20 2159 2165 10.1200/JCO.2013.53.9288 24912899
6 Russell SD Blackwell KL Lawrence J Pippen JE Roe MT Wood F Independent adjudication of symptomatic heart failure with the use of doxorubicin and cyclophosphamide followed by trastuzumab adjuvant therapy: a combined review of cardiac data from the National Surgical Adjuvant breast and Bowel Project B-31 and the North Central Cancer Treatment Group N9831 clinical trials J Clin Oncol 2010 28 21 3416 3421 10.1200/JCO.2009.23.6950 20530275
7 Bowles EJ Wellman R Feigelson HS Onitilo AA Freedman AN Delate T Risk of heart failure in breast cancer patients after anthracycline and trastuzumab treatment: a retrospective cohort study J Natl Cancer Inst 2012 104 17 1293 1305 10.1093/jnci/djs317 22949432
8 Zibelman M Goldstein LJ. Seven-year follow-up assessment of cardiac function in NSABP B-31, a randomized trial comparing doxorubicin and cyclophosphamide followed by paclitaxel (ACP) with ACP plus trastuzumab as adjuvant therapy for patients with node-positive, human epidermal growth factor receptor 2–positive breast cancer Breast diseases: a year book quarterly 2013 3 24 269 270
9 Seidman A Hudis C Pierri MK Shak S Paton V Ashby M Cardiac dysfunction in the trastuzumab clinical trials experience J Clin Oncol 2002 20 5 1215 1221 10.1200/JCO.2002.20.5.1215 11870163
10 Kuramochi Y Guo X Sawyer DB. Neuregulin activates erbB2-dependent src/FAK signaling and cytoskeletal remodeling in isolated adult rat cardiac myocytes J Mol Cell Cardiol 2006 41 2 228 235 10.1016/j.yjmcc.2006.04.007 16769082
11 Finkelman BS Putt M Wang T Wang L Narayan H Domchek S Arginine-nitric oxide metabolites and cardiac dysfunction in patients with breast cancer J Am Coll Cardiol 2017 70 2 152 162 10.1016/j.jacc.2017.05.019 28683962
12 Sandoo A Kitas GD Carmichael AR. Endothelial dysfunction as a determinant of trastuzumab-mediated cardiotoxicity in patients with breast cancer Anticancer Res 2014 34 3 1147 1151 24596352
13 Fischer D Rossa S Landmesser U Spiekermann S Engberding N Hornig B Endothelial dysfunction in patients with chronic heart failure is independently associated with increased incidence of hospitalization, cardiac transplantation, or death Eur Heart J 2005 26 1 65 69 10.1093/eurheartj/ehi001 15615801
14 Berrazueta JR Guerra-Ruiz A García-Unzueta MT Toca GM Laso RS Adana MS Endothelial dysfunction, measured by reactive hyperaemia using strain-gauge plethysmography, is an independent predictor of adverse outcome in heart failure Eur J Heart Fail 2010 12 5 477 483 10.1093/eurjhf/hfq036 20354033
15 Higashi Y. Assessment of endothelial function. History, methodological aspects, and clinical perspectives Int Heart J 2015 56 2 125 134 10.1536/ihj.14-385 25740586
16 Ras RT Streppel MT Draijer R Zock PL. Flow-mediated dilation and cardiovascular risk prediction: a systematic review with meta-analysis Int J Cardiol 2013 168 1 344 351 10.1016/j.ijcard.2012.09.047 23041097
17 Cai H Harrison DG. Endothelial dysfunction in cardiovascular diseases: the role of oxidant stress Circ Res 2000 87 10 840 844 10.1161/01.res.87.10.840 11073878
18 Hayward CS Kraidly M Webb CM Collins P. Assessment of endothelial function using peripheral waveform analysis: a clinical application J Am Coll Cardiol 2002 40 3 521 528 10.1016/s0735-1097(02)01991-5 12142121
19 Widmer RJ Lerman A. Endothelial dysfunction and cardiovascular disease Glob Cardiol Sci Pract 2014 2014 3 291 308 10.5339/gcsp.2014.43 25780786
20 Aird WC. Spatial and temporal dynamics of the endothelium J Thromb Haemost 2005 3 7 1392 1406 10.1111/j.1538-7836.2005.01328.x 15892866
21 Hoffman RK Kim BJ Shah PD Carver J Ky B Ryeom S. Damage to cardiac vasculature may be associated with breast cancer treatment-induced cardiotoxicity Cardiooncology 2021 7 1 15 10.1186/s40959-021-00100-3 33875012
22 Gabrielson K Bedja D Pin S Tsao A Gama L Yuan B Heat shock protein 90 and ErbB2 in the cardiac response to doxorubicin injury Cancer Res 2007 67 4 1436 1441 10.1158/0008-5472.CAN-06-3721 17308081
23 Keulenaer GW Doggen K Lemmens K. The vulnerability of the heart as a pluricellular paracrine organ: lessons from unexpected triggers of heart failure in targeted ErbB2 anticancer therapy Circ Res 2010 106 1 35 46 10.1161/CIRCRESAHA.109.205906 20056944
24 Cai H Harrison DG. Endothelial dysfunction in cardiovascular diseases: the role of oxidant stress Circ Res 2000 87 10 840 844 10.1161/01.res.87.10.840 11073878
25 Choi JY Barlow WE Albain KS Hong CC Blanco JG Livingston RB Nitric oxide synthase variants and disease-free survival among treated and untreated breast cancer patients in a Southwest Oncology Group clinical trial Clin Cancer Res 2009 15 16 5258 5266 10.1158/1078-0432.CCR-09-0685 19671875
