The aim of this study was to explore potential risk factors for the development of BCRL in breast cancer patients who received NAC and ALND. In our study, we identified five independent risk factors: radiotherapy, duration of NAC, number of lymph nodes removed, duration of drainage, and postoperative sleeping position. Our study has a large number of patient data and an adequately followed-up period; we believe our research could bring more credible evidence to change management strategies and patient care.
Placement of a closed-suction drain in the mastectomy site and axilla after breast cancer surgery is to decrease postoperative complications, particularly seroma formation [21–23]. However, in our study, we found that Patients with a longer duration of drainage were at higher risk of BCRL. Likewise, Saadet et al. stated that the long duration of the axillary drain was a risk factor for BCRL (P = 0.045) [24]. Two reasons may explain this phenomenon. Firstly, a longer duration of drainage reflects a higher degree of lymphatic vessel damage, supporting that more extensive axillary surgery increases the incidence of BCRL [25]. Secondly, Patients with drainage tubes need to immobilize the affected limb to reduce drainage[26]. However, carrying the drainage tube for a long time can lead to stiffness in the arm and inevitably, the optimal time for post-operative rehabilitation exercises is missed. A cross-sectional study of 766 patients showed that women who exercised their affected arm decreased the risk of developing BCRL through a potential mechanism called “muscle pump” [12].
A meta-analysis reported that the decision to remove drainage based on the amount of drainage would reduce the incidence of seroma, an independent risk factor for lymphedema [27], compared to short-term removal of drainage [28]. However, due to management regarding drain placement, the number of drains, and hospitalization varying widely between breast units [29], there are no widely applicable criteria for the removal of drainage. Therefore, future multicenter and larger cohort studies based on uniform criteria are required to better understand the relationship between drainage time and BCRL.
The relationship between postoperative sleeping position and BCRL has never been studied before. Our study found that sleeping biased towards the affected arm significantly increased the incidence of BCRL (HR = 3.027). Prolonged compression of the affected limb impedes the return of lymphatic fluid, disrupting the morphology and function of the lymphatic system and ultimately leading to BCRL. Besides, prolonged compression of the limb leads to ischemia of the subcutaneous tissues, causing a reduction in subcutaneous fat and muscle atrophy, which further affects the functional recovery of the lymphatics. Patients often consciously avoid putting pressure on the affected arm in the early postoperative period. However, later in life, they may think they have recovered from breast cancer and may unconsciously sleep on the affected side. This result demonstrates that some breast cancer survivors are under-aware of BCRL, highlighting the importance of correcting postoperative sleep position.
The association between radiotherapy and BCRL is well documented in the literature [30–33]. In our study, patients who received radiotherapy were 1.8 times more likely to develop BCRL than those who did not. A retrospective study of 7617 patients showed patients with more extensive radiation fields were at greater risk of lymphedema; compared with no radiation or breast/chest wall radiation alone, regional lymph node irradiation (RNI) increased the risk of BCRL by 2–4 times [31]. In addition, similarly, the total lymph nodes removed is another well-known independent risk factor for BCRL [6, 8, 34, 35]. Hwa Kyung Byun et al. reported that the 3-year cumulative BCRL rates were 3.0%, 10.0%, 20.2%, and 24.4% in patients with 0 to 5, 6 to 10, 11 to 15, and > 15 lymph nodes removed, respectively (P < 0.001) [31]. Interestingly, several reports suggest that the combination of ALND and radiotherapy has a synergistic effect on the development of BCRL [8, 32, 33]. However, The relationship between radiotherapy regimens and the number of lymph nodes removed has rarely been studied, which may be helpful in developing individualized radiotherapy regimens for breast cancer patients receiving axillary dissection to reduce the incidence of BCRL.
In recent years, increasing attention has focused on studying the risk factors for BCRL in the NAC setting. Giacomo Montagna et al. found that NAC was an independent risk factor for BCRL (OR = 2.10 ; 95%CI = 1.16–3.95 ; P = 0.01) [36]. Our study suggests that lower incidence of BCRL in patients with shorter duration NAC, which is in line with a study reporting that the longer NAC duration was correlated with increased BCRL incidence [17]. In general, there are two possible factors contributing to this result. Firstly, the number of cycles of chemotherapy infusion in the ipsilateral arm was reported as an independent risk factor for developing BCRL by Jose´ Luiz B. Bevilacqua et al. [37]. Secondly, regarding the specific toxicity of chemotherapy agents, many studies showed that taxane-based chemotherapy could result in BCRL by increasing extracellular fluid accumulation [38–40]. Therefore, more attention should be paid to patients with longer duration of NAC and treated with taxane-based chemotherapy.
The limitations of this study were as follows: Firstly, in our study, BCRL was diagnosed by objective measures only, lacking a subjective approach, which may have contributed to missing some potential patients. However, according to a meta-analysis, objective measures are the most used diagnostic criteria for lymphedema [41]. What’s more, we only considered whether radiotherapy was administered and did not analyze the impact of different chemotherapy regimens. But there have been many studies showing that RNI is associated with a higher risk of developing BCRL than radiation to the breast or chest wall alone [31, 33, 41]. In addition, a strength of our study is that we collected uniform bilateral arm measurements at several time points up to 30 months, including pre-surgical measurement, to reduce the impact of the patient's initial body size differences.