One in 10 Danish women have breast cancer during their lifetime^1,2, with 2.3 million new cases globally in 2020³, making breast cancer the most frequent cancer among women. Advances in treatment have significantly improved survival rates⁴, shifting attention toward managing long-term complications such as arm lymphedema.^5,6 Various factors influence the incidence of arm lymphedema, including the type of surgery, body mass index (BMI), and adjuvant therapy.⁷ Furthermore, lymphedema is linked to chronic pain, fatigue, heaviness, and functional impairments, which profoundly impact the patient's quality of life and sleep quality.^8-12

A recent systematic review including 2 343 878 patients found that breast-conserving surgery combined with radiotherapy is associated with improved survival compared to mastectomy.¹³ Specifically, the findings indicate that breast-conserving surgery for patients with early-stage breast cancer remains consistent, regardless of whether mastectomy is performed with or without radiotherapy. Consequently, this recent advancement may increase the demand for oncoplastic reconstruction as patients and clinicians aim to optimize oncologic outcomes in breast cancer treatment.

Although a study found aesthetic outcomes to be significantly higher for breast-conserving surgery than the modified radical mastectomy group¹⁴, not all patients have satisfactory aesthetic results. Consequently, oncoplastic breast-conserving surgery (OBCS) has been increasingly adopted to enhance aesthetic outcomes following breast cancer surgery.^15,16 OBCS integrates oncologic and reconstructive techniques and involves volume replacement, reduction, and displacement following breast-conserving surgery.¹⁷ However, despite the rising popularity and demonstrated aesthetic benefits of OBCS¹⁸, the impact of this approach on the development of arm lymphedema remains unclear.

The incidence of arm lymphedema following breast cancer surgery is highly variable (4% to 40%) and depends on factors such as surgical technique, extent of axillary intervention, and adjuvant therapies.⁷ While the risk factors for lymphedema following conventional breast-conserving therapy and mastectomy are relatively well-documented, the incidence and contributing factors following OBCS remain poorly defined. Some studies suggest that the extensive tissue rearrangement in OBCS could disrupt lymphatic pathways, increasing the risk of arm lymphedema. For example, Oberhauser et al. found a higher incidence of chronic pain and lymphedema in OBCS patients compared to conventional breast-conserving surgery, highlighting a potential link between tissue manipulation and lymphatic disruption.¹⁹

Notably, OBCS allows for more extensive tumor excision with immediate volume replacement or redistribution, potentially reducing the need for mastectomy while improving cosmetic results.¹⁵ Indeed, manipulating breast tissue and the potential for increased vascular and lymphatic disruption raise concerns about elevated risks of postoperative lymphedema. Although previous research has explored arm morbidity after oncoplastic surgery²⁰, there is a lack of comprehensive evidence regarding its effect on arm lymphedema.

Given the physiological mechanisms involved in arm lymphedema, it is plausible to hypothesize that OBCS may contribute to a different risk of lymphedema compared to other surgical techniques that involve more manipulation of breast tissue with the inherent lymphatic structures. However, various techniques are used for OBCS, where adjacent tissues (perforator flaps) reconstruct the missing part of the breast. This could perhaps alleviate the inherent risk of lymphedema as a consequence of axillary surgery/staging. An example is the latissimus dorsi flap, which has been suggested to serve as a lymphatic bridge as it traverses the axillary region²¹, where lymph node surgery and radiation impair lymphatics. With confirmed lymphedema risk after OBCS, guidelines should update preoperative counseling and lymphatic-preserving techniques. Conversely, if OBCS demonstrates reduced lymphedema risk, this would further support its adoption as a breast-conserving strategy, offering both aesthetic and psychological benefits. Because preoperative fear of lymphedema contributes to postoperative anxiety, early education may help alleviate concerns and improve patient outcomes.²² Therefore, clarifying this relationship will enhance patient counseling and guide preventive strategies.

This scoping review systematically maps existing literature to assess reported effects of OBCS on arm lymphedema, identifying knowledge gaps to guide future research.

This scoping review was conducted as part of a systematic review focusing on lymphedema outcomes following breast cancer surgery, with the protocol registered in the Prospective Register of Systematic Reviews (PROSPERO: CRD42024506355). Two independent authors screened all titles, abstracts, and full texts. All citations and screening were handled by Covidence (View Website). Only a limited number of studies met the inclusion criteria for oncoplastic surgery. We therefore conducted a scoping review to analyze relevant studies identified through our PROSPERO-registered systematic review, allowing for a comprehensive assessment of current evidence gaps. Through collaborative discussion, the authors developed a data-charting form to establish the variables for extraction. One author performed the data extraction, which was then independently verified by a second author. The data-charting form was continuously updated in an iterative process. The risk of bias was assessed independently by 2 authors using the Methodological Index for Non-Randomised Studies (MINORS) tool²³ (Supplementary Table 1). The MINORS is a valid instrument designed to assess the methodological quality of nonrandomized surgical studies, whether comparative or noncomparative; any discrepancies were resolved through discussion. The search strategy and data extraction can be seen in Table 1 and Supplementary Table 2.

We used a descriptive approach to synthesize the extracted data. Key study characteristics were presented in tabular format (Table 2; Supplementary Table 2), while methodological gaps, patterns, and variations were analyzed through narrative synthesis.

The systematic search found 4185 publications (see PRISMA chart Figure 1). Four studies adhered to the original criteria from the PROSPERO protocol.^24-27 In addition, 1 study, which had been excluded due to an unspecified method of measuring lymphedema, was included in this review.¹⁹ Lauritzen et al. studied volume replacement methods with lateral intercostal artery perforator flaps (n = 3), muscle-sparing latissimus dorsi flaps (n = 1), and volume displacement (n = 7).²⁶ Oberhauser et al. used tumorectomy with replacement methods or glandular flaps (Grisotti [n = 6]), oncoplastic mastopexy (Benelli [n = 70], V-mammoplasty [n = 21], and Hemibatwing [n = 33]), and oncoplastic reduction mammoplasty (defined by the use of glandular flaps, nononcologic skin, and tissue resection).¹⁹ In the study by Gowda et al., oncoplastic reduction was used but not further specified²⁴, while 2 studies did not describe the specific type of oncoplastic surgery.^25,27 The analysis comprised 1532 patients with 510 oncoplastic surgeries from the 5 publications, with follow-up periods ranging from 12 months to 7.4 years. Assessments by MINORS yielded an average of just 53.75% of the total possible points. Key contributing factors included the absence of prospective sample size calculations in all studies, only 1 study reporting loss to follow-up²⁶, short follow-up periods, and a lack of documented pre-established study protocols. All included studies, presented in Table 2, were published after 2019.

Three of the 5 studies report the rate of lymphedema related to OBCS: Gowda et al. report a rate of 11% (6 of 54 patients), Lauritzen et al. report a rate of 0% (0 of 11 patients), and Oberhauser et al. report a rate of 5.9% (11 of 188 patients). In total, 17 of 253 patients presented with lymphedema, resulting in an overall rate of 6.7%. Lauritzen et al. and Gowda et al. suggest that oncoplastic surgery does not significantly alter the risk of arm lymphedema compared to other surgical approaches. Oberhauser et al. found a potential increased long-term risk but did not describe the diagnostic criteria or measurement method of lymphedema. However, the reviewed studies did not necessarily focus on lymphedema outcomes. For example, Silva et al. and Obi et al. did not report the rate of arm lymphedema related to OBCS nor the difference between OBCS and breast-conserving surgery. Silva et al. aimed to validate a quality-of-life questionnaire, failing to present any lymphedema data related to oncoplastic surgery, while Obi et al. focused on evaluating outcomes following intraoperative radiation therapy and did not deal with lymphedema or oncoplastic surgery.

Risk factors for lymphedema are a BMI greater than 25, axillary surgery, pathology, chemotherapy, and radiotherapy.⁷ In 4 of the 5 studies, mean BMIs were reported to range from 25.7 to 29. All studies included data on axillary intervention, chemotherapy, and radiotherapy but were not necessarily related to either breast cancer-related lymphedema (BCRL) or oncoplastic surgery. Obi et al. and Brandini da Silva et al. did not report baseline values for either lymphedema vs. non-lymphedema or BCS vs OBCS. In contrast, Lauritzen et al. only included oncoplastic procedures²⁶, and as no patients developed arm lymphedema, no comparison was possible. Oberhauser et al. reported baseline values for OBCS vs BCS but not lymphedema vs. non-lymphedema. On the contrary, Gowda et al. did not report baseline values for OBCS vs BCS. Gowda et al. did, however, describe differences between the BCS and the OBCS group, as they found patients with OBCS had a higher BMI, larger breast mass removed, and were less likely to receive sentinel lymph node biopsy (SLNB) and boost radiation, although supraclavicular radiation was more common in this group. They also reported baseline values for lymphedema vs. non-lymphedema, where they found neoadjuvant therapy, high BMI, radiation, and large breast mass resection as risk factors;²⁴ only breast specimen mass, axillary radiation, and neoadjuvant therapy were significantly associated with lymphedema on multivariable analysis. Regardless of the type of breast surgery, 2 studies found a connection between axillary lymph node dissection and lymphedema.^24,25 Supplementary Table 3 summarizes the data on known risk factors extracted from all 5 studies.

This review reveals a notable lack of evidence on the topic. Current data do not conclusively link OBCS to a higher or lower risk of lymphedema compared to other procedures.

The pathophysiology of lymphedema is highly complex; however, for BCRL, it essentially begins with the interruption of lymphatic flow in the arm²⁸. This results in an overload of protein-rich fluid in the interstitium, causing an inflammatory response, in which the deposition and remodeling of adipose tissue, depletion of growth factors such as vascular endothelial growth factor C (VEGF-C), and infiltration of CD4⁺ cells all contribute to chronic lymphedema.^29,30 Although oncoplastic surgery generally spares the axillae, the impact of individual techniques on lymphedema prevalence remains unclear and warrants investigation. Unfortunately, not all studies included data on the level of oncoplastic surgery, and only Lauritzen et al. reported on the relationship between level of oncoplastic surgery and lymphedema outcome.²⁶

A few other risk factors for arm lymphedema were identified in the included studies, but the relationship between these and OBCS was not investigated. BMI and breast size may potentially confound arm lymphedema risk after OBCS, though the reviewed studies were not designed to assess this relationship. The findings by Lauritzen et al. suggest a risk of breast lymphedema rather than arm lymphedema, which has recently been explored in a study on the effect of oncoplastic surgery on breast lymphedema³¹, where an increased risk of breast lymphedema was found to be associated with an increased breast volume, but not with OBCS. The relationship between breast lymphedema and breast-conserving surgery has recently been explored in a review³², which found BMI, breast size, tumor size, tumor site, type of surgery (not further specified), and adjuvant therapy to be potential risk factors.

The study by Oberhauser¹⁹ was the only study that found oncoplastic surgery to be a potential risk factor for arm lymphedema. Our analysis revealed that 77.9% of patients in the BCS group received radiotherapy, compared to 85.6% in the OBCS group. Additionally, more patients with OBCS underwent chemotherapy compared to those with BCS in the study by Oberhauser. The higher lymphedema incidence rate found for OBCS could potentially be attributed to radiation and/or chemotherapy. Gowda et al. found that patients who received oncoplastic reduction were less likely to receive boost radiation (P < 0.01).²⁴ but were more likely to receive supraclavicular radiation (P = 0.04). Radiotherapy administration rates varied across studies. Lauritzen et al. reported that 90.9% of OBCS patients underwent radiotherapy, while Obi et al. documented universal radiotherapy administration in their cohort. However, Silva et al. did not provide comparative data between surgical approaches.²⁷

BCRL imposes both clinical and financial burdens³³, requiring long-term management as a chronic condition. Complex decongestive therapy (CDT) is the standard conservative treatment consisting of compression garments combined with manual lymphatic drainage, skin care, patient education, and therapeutic exercise³⁴, which all require therapist involvement and often ongoing maintenance. Boyages et al. found the mean financial cost of conservative lymphedema treatment to be A\$977 per 12 months. A recent study found surgical treatment such as lymphaticovenous anastomosis (LVA) or vascularized lymph node transfer (VLNT) to be more cost-effective compared to CDT after 2 years postoperatively.³⁵ VLNT and LVA can both be combined with breast reconstruction^36,37, reducing the overall cost of surgery, although it is not known how often these procedures are combined with OBCS. Theoretically, minimizing the number of surgeries could lower overall costs to the patient and health system.

In addition, psychological factors such as fear of lymphedema play a crucial role in patient experience and quality of life. Jammallo et al. found that preoperative fear, younger age at diagnosis, and axillary lymph node dissection were significantly associated with higher postoperative fear of lymphedema, profoundly affecting patients' mental health and physical activity.²² Fear of lymphedema may be an underestimated factor that impacts patient recovery and adherence to recommended rehabilitation practices, emphasizing the need for targeted psychological interventions as part of routine care. This underscores the need to investigate predisposing surgical factors like OBCS, while emphasizing the importance of preoperative education and long-term psychological support for surgical breast cancer patients.

Major limitations identified across the reviewed studies are the inconsistency in measuring lymphedema and the lack of long-term follow-up data, as reflected in the low MINORS score of only 53.75%. Additionally, most studies did not specifically differentiate between various types of oncoplastic surgery, making it difficult to conclude on specific OBCS techniques and their impact on lymphedema risk. These limitations are partly due to arm lymphedema not being the main focus of the studies. All identified studies were published after 2019, indicating that this area is a relatively new field of interest and could explain the scarcity of studies on the subject. Future research is needed with a specific focus on arm lymphedema after OBCS. In particular, prospective studies are required with a larger sample size, standardized measurements of lymphedema including objective baseline measurements, and information on known risk factors for arm lymphedema as well as oncoplastic techniques used to evaluate the association between specific OBCS techniques and arm lymphedema risk.

This review identified significant knowledge gaps in the literature regarding the long-term effects of oncoplastic surgery on arm lymphedema. The majority of the studies lack detailed analyses of specific OBCS techniques, and few have evaluated the long-term incidence of lymphedema beyond the immediate postoperative period. Addressing these gaps is crucial not only for improving patient outcomes and guiding clinical decision-making but also for improving patient information and education, which can help minimize the potential fear of long-term side effects of breast cancer treatment.