The current study found that the prevalence of patients with lymphedema after treatment for breast cancer was 44.8%. However, it is possible that underestimation occurred because the average time spent in the postoperative period in our sample was 5 years, and the higher a woman’s exposure to risk factors, the greater the chances of developing lymphedema. The possibility of survival bias cannot be ruled out because more severe cases subjected to more drastic measures may not have maintained contact owing to death, and therefore were not included in this sample. The prevalence of lymphedema found in this study is higher than the prevalence rates between 9% and 40% reported by other studies [8, 9, 12, 15, 16, 18, 19]. This difference between prevalence rates could be attributed to the type of method used to diagnose lymphedema, because there are several methods for measuring arm volume, [7, 14, 17, 19] and because of the fact that the institution in which the data were collected does not offer a service specializing in prevention and treatment of lymphedema. Perimetry, which was the diagnostic method used in this study, is based on comparing the measurement of the circumference of the affected arm with the contralateral arm [7, 9, 14, 17]. Furthermore, in Brazil, delayed diagnosis is common, causing more aggressive surgeries, which could be an important reason for the high prevalence of lymphedema in this study.
Age is a variable often associated with lymphedema [7, 19–22]. Along with the aging process, anatomical and physiological changes related to lymphatic obstruction occur, which may predispose to the development of lymphedema, with the main mechanism being the opening of lympho-venous anastomoses [7, 22–24]. The higher incidence of lymphedema in older patients observed in some studies [7, 19, 23, 25] may be due to a progressive loss of these anastomoses because of the aging process [12, 24]. This finding was not observed in the current study, where the average age of the patients with lymphedema was 56 years, with no significant difference between those with and those without lymphedema. Likewise, a study by Yen et al.,  who investigated self-reporting of the risk factors for lymphedema in older women, also found no significant difference between women with and those without lymphedema. The difference in evaluation methods and the average age of the women involved in these studies may be responsible for the discrepancy of results.
In attempting to reestablish the lympho-venous balance of the upper limb and breast region after breast cancer treatment, the body makes use of compensatory mechanisms, which attempt to avoid edema. However, some factors such as trauma, aging, and repetitive or non-repetitive episodes of infections can overwhelm the lymphatic system, changing the balance. Therefore, the longer the time elapsed since surgery, the greater the risk of developing lymphedema, because this increases the chances of a woman being exposed to injury .
Radiotherapy is considered as a risk factor for development of lymphedema, mainly when axillary irradiation is applied [7, 13, 26]. A likely explanation is the occurrence of lymphedema due to the blockage of lymph vessels or their compression by fibrosis caused by this treatment [25, 27, 28]. According to Bergmann et al.,  the main risk factor associated with lymphedema after treatment for breast cancer is the axillary approach, both surgical and radiotherapy, followed by age. Our study differs from previous studies in that there was no association between the irradiation site and the development of morbidity when controlled by other variables.
AWS, otherwise known as superficial lymphatic thrombosis, is the formation of a palpable network of cords that can extend from the armpit, through the antecubital space to the base of the thumb. AWS is caused by possible formation and displacement of fibrin clots in the superficial veins and lymphatic capillaries, which form a network [8, 20, 29]. In the current study, the presence of AWS in bivariate analysis was statistically significant (p<0.001). However, when AWS was analyzed in the adjusted model, it lost its significance. This syndrome is accompanied by acute pain symptoms that may regress spontaneously (~3 months after surgery) or become chronic, when the formation of a fibrotic cord occurs, and this restricts the range of motion of the shoulder [30, 31]. The presence of AWS contributes to the formation or worsening of lymphedema [26, 29, 31].
Some studies question the validity of current guideline “manuals” for the prevention of lymphedema, because they believe that despite the biological plausibility, no evidence has been shown for the validity of these treatments [6, 7, 32]. Therefore, it is prudent for the patient to take certain care of the arm, but this should not affect or impair the patient’s daily routine. The occurrence of minor injuries, such as cuts, bruises, minor burns, and infection, triggers an inflammatory response. This translates into an increase of fluid filtered by the arterial capillaries into the interstitium, capillaries and lymphatic vessels, which overloads the lymphatic system already damaged by lymphadenectomy [10, 12, 20, 24]. This process may intensify, generating local symptoms, as well as general symptoms, giving rise to the appearance of erysipelas and/or lymphangitides [20, 25, 27]. The removal of cuticles during nail care allows easy access to bacteria, by producing a skin lesion, facilitating an inflammatory process that can precede or aggravate lymphedema [4, 19, 26].
The prevalence of moderate to severe symptoms in women who avoid movement of the ipsilateral arm after surgery is significantly higher than in those who do not avoid it. These data are corroborated by several studies [6, 9, 16, 20] in which changes in movements of the shoulder after surgery for breast cancer were investigated, at various times after surgery, to determine the effect of early exercise intervention through physiotherapy [18, 32, 33]. In the present study, only 119 women (47.6%) received some type of information concerning various treatments for the limb and the importance of early motion. In this case, besides harm from the lack of intervention supervised by a professional, the guidance of self care alone leads to misinterpretation, resulting in failure to perform adequate exercises. Studies of lymphedema have shown a positive association between the receipt of information and the avoidance of movement [7, 16, 20, 34, 35]. In our study, an important association was found between lymphedema and the lack of information regarding movement of the limb, although this was not statistically significant in multivariate analysis.