Abstract
BACKGROUND:
One of the dreaded complications after the treatment of breast cancer is lymphedema. Therapies used in the treatment of breast cancer such as surgery, radiotherapy, hormone therapy and chemotherapy may be adversely affected by obesity.
AIM:
The objective of this study was to use bioimpedance to assess abdominal fat in women with breast cancer treatment-related lymphedema and suggest this as a screening method.
METHODS:
Forty-five female patients with clinical diagnosis of breast cancer treatment-related lymphedema were evaluated in this quantitative cross-sectional study. A control group, composed of 38 patients with varicose veins and women attending a social support group, was matched for age and body mass index (BMI). All participants were submitted to a bioimpedance evaluation (In Body S 10), with particular attention being paid to abdominal fat and their BMI. The unpaired t -test, Fisher Exact test and Mann–Whitney test were used for statistical analysis and an alpha error of 5%.
RESULTS:
There was no significant difference (p -value = 0.23) in the mean BMI
between the study group (27.79
CONCLUSION:
Overweight and obese women with breast cancer treatment-related lymphedema are more likely to have increased abdominal fat than the general population with bioimpedance.
Introduction
Breast cancer is the commonest cancer in women worldwide, both in developed and underdeveloped countries, accounting for around 22% of new cases annually [1].
Available therapy includes surgery and radiotherapy for local treatment and hormone therapy and chemotherapy for systemic treatment. Sentinel lymph node biopsy is accepted as the standard procedure to diagnose early-stage breast cancer [2,3].
One of the dreaded complications after the treatment of breast cancer is lymphedema. Lymphedema is characterized as an abnormal accumulation of protein-rich fluid in the tissues resulting from dysfunction of the lymphatic system, which causes an imbalance between the formation of lymph and its absorption in the initial lymphatic system [4,5].
All the therapies used in the treatment of breast cancer such as surgery, radiotherapy, hormone therapy and chemotherapy may be adversely affected by obesity. A recent study shows that 1 in 4 women who received chemotherapy in the treatment of breast cancer have a weight gain of up to 11 kg during the first year after diagnosis [6]; this can be explained by decreased physical activity, increased food intake and the effects of corticosteroids [7].
Obesity may also be associated with hormonal profiles that stimulate growth of breast cancer. Observational studies show that women with breast cancer who are overweight or gain weight after diagnosis have a higher risk of relapse or death compared to women with normal BMIs [8].
After breast cancer treatment, obesity is associated with worse survival independent of the number of resected axillary lymph nodes [9]. Hence, one of the problems observed in these women is obesity and an increase in abdominal fat, both of which are cardiovascular risk factors [8,10,11]. There may be a minimum level of visceral and abdominal fat independent of the BMI, which may be associated with the triglycerides level and insulin resistance [11]. Thus weight control plays an important role in the rehabilitation and recovery of quality of life, general health and survival of women who suffered breast cancer [8].
Bioelectrical impedance is a noninvasive and practical method of assessing body composition including abdominal fat [12–14]. The assessment of abdominal fat by bioelectrical impedance increases the options in the epidemiological evaluation of obesity. The aim of this study was to evaluate abdominal fat in women with breast cancer treatment-related lymphedema and suggest bioimpedance as a method to screen these women.
Method
Forty-five female patients with clinical diagnosis of breast cancer treatment-related lymphedema were evaluated in this quantitative cross-sectional study. A control group, composed of 38 patients with varicose veins and women attending a social support group, was matched for age and body mass index (BMI). The study was conducted at the Clinic Godoy in 2013.
Patients with breast cancer treatment-related lymphedema were enrolled in this study in order of arrival. Diagnosis of the lymphedema was measured by the water displacement technique and was defined as a difference in volume of >200 mL compared to the contralateral arm. Patients with causes of lymphedema not related to breast cancer and those with active infections were excluded from the study.
All participants were submitted to a bioimpedance evaluation (In Body S 10), with particular attention being paid to abdominal fat and BMI. The test was performed with the subject in the supine position with arms and legs abducted at an angle of 45∘ .
The unpaired t -test, Fisher Exact test and Mann–Whitney test were used for statistical analysis with an alpha error of 5% being considered statistically significant. The study was approved by the Research Ethics Committee of the Medical School in Sao Jose do Rio Preto (#296/2011) and the protocol was sent to the Brazilian Clinical Trials Register (ReBEC-#305).
Results
The mean ages of the women in the study and control groups were 61.31 and 61.07 years,
respectively. There was no significant difference (unpaired t -test;
p -value = 0.23) in the mean BMI between the study group
(27.79
Tables 1 and 2 show the BMI and its correlation with the amount of abdominal fat in the study and control groups, respectively. In respect to overweight patients, the study group had more abdominal fat than the control group, (Fisher’s exact test;p -value = 0.0003). Moreover, on comparing obese patients, the study group had more abdominal fat (Fisher’s exact test; p -value = 0.02). However, no significant difference was observed for non-obese patients comparing the study and control groups (Fisher’s exact test; p -value = 0.6).
The comparison of obese patients with non-obese patients in the control group identifies an association between obesity and abdominal fat (Fisher’s exact test; p -value < 0.04).
Discussion
Using bioimpedance, the present study found that women with breast cancer treatment-related
arm lymphedema have increased abdominal fat compared to a control group. However obesity in
the control group was also associated with increased abdominal fat. In this study, 79.17% of
the study group and 22.22% of the control group who were classified as overweight presented
with levels of abdominal fat of more than 100
However, some changes that take place during the aging process should be taken into account. Changes in body compartments were observed such as decreased body mass, height, and muscle mass, but with an increase and with redistribution of body fat. This study detected that peripheral adipose tissue tends to decrease with accumulating in the abdominal region [15].
After breast cancer treatment, patients have a number of complications that aggravate the physical aspect such as lymphedema and breast amputation. Weight gain is another negative factor from psychologically and physically points of view; it can limit mobility and increase the risk of the recurrence of breast cancer and other malignancies. Besides hindering the treatment of lymphedema, obese people have more difficulty in adapting to compression mechanisms and have a lower therapeutic response [16,17].
This study evaluates one more negative aspect of these patients, the association of obesity
with abdominal fat. Obesity in both the control group and the study group is associated with
abdominal fat, however it is more prevalent in the study group. Although the sample size in
this analysis was small, no association was found with abdominal fat in underweight and
normal-weight subjects in the control and study groups. Only 12.5% of the group of patients
classified with normal weight had more than 100
The cause of the change in fat distribution in patients after breast cancer treatment is not well understood, but chemotherapy seems to be the most plausible hypothesis for this alteration [17]. In general the female population has been gaining weight in recent years. Breast cancer has a number of both psychological and physical changes that impede weight control [18]. However, the aggravating feature of obesity is the distribution of fat to the most critical region of the body, the abdomen. Abdominal fat is associated with cardiovascular complications such as, arteriosclerosis, hypertension and coronary heart disease [8].
These findings suggest that women after breast cancer treatment should be advised and guided by a rehabilitation team about the importance of a balanced diet to control weight. These patients need to be aware of the consequences of increased weight and increased abdominal fat.
Several methods are used to evaluate abdominal fat including hydrostatic weighing, computed tomography and bioimpedance. Computed tomography is the standard evaluation method, but this exam is very costly. In recent years however bioimpedance has been described as a more practical and inexpensive alternative [12,13]. The apparatus used in this study is an Inbody S10 which allows a broad-ranging evaluation of the intra- and extra-cellular water and lean mass of the trunk and extremities.
In the literature, several studies recommend the use of bioimpedance to estimate visceral fat [13,14]. Thus, this approach, due to its non-invasiveness and low cost could become an important screening tool for abdominal fat. However, the validation of bioimpedance devices is important to validate this method.
Conclusion
Overweight and obese women with breast cancer treatment-related lymphedema are more likely to have increased abdominal fat than the general population. Bioimpedance may be a method useful to screen these patients.
Conflict interest
The authors declared no has competing financial interests.