A major clinical trial across Europe shows that many women with limited spread to underarm lymph nodes can avoid additional surgery and its long-term risk of lymphoedema by receiving radiotherapy, with no loss in survival and improved arm function.
The management of underarm lymph nodes in breast cancer has important consequences for long-term quality of life. New trial results presented at the annual meeting of the American Society of Clinical Oncology in Chicago examined whether women whose cancer had spread to one or two axillary lymph nodes could safely avoid the traditional surgical removal of additional nodes.
The study tracked functional outcomes and survival, suggesting that avoiding axillary lymph node dissection can substantially reduce the burden of lymphedema while maintaining comparable disease control.
These findings have practical implications for clinicians and patients deciding between further surgery and targeted radiotherapy.
The trial included women who had either breast-conserving surgery or a mastectomy, and it specifically addressed a previous uncertainty: whether the omission of axillary surgery was safe for larger tumours or for patients undergoing mastectomy. The results provide evidence to inform shared decision-making around axillary treatment.
Design and scope of the trial
The European study enrolled 2,540 women from Sweden, Denmark, Germany, Greece and Italy, with an average age near 61. All participants had breast cancer that involved one or two nearby axillary lymph nodes. Patients were randomly assigned to receive either an axillary lymph node dissection (ALND) followed by radiation or radiation alone without ALND. About one third of the participants had chosen to undergo mastectomy at the time of their primary breast treatment.
To measure arm-related outcomes, researchers used validated patient questionnaires collected at one, three and five years after treatment. Items asked about everyday tasks — for example the ability to lift heavy objects or drive — alongside breast cancer–specific symptoms such as fatigue, cognitive complaints and mood changes. Responses were scaled numerically so that higher scores reflected more severe arm dysfunction or symptoms.
Main findings: function, complications and survival
At five years of follow-up, women who avoided ALND and received radiation alone reported significantly better arm function than those who had additional axillary surgery. The trial also found that the omission of ALND did not reduce survival; in fact, the group that did not undergo node removal had a slightly higher five-year survival rate, with approximately 94 percent surviving at least five years. These outcomes support the conclusion that more extensive axillary surgery in this patient group does not improve oncologic outcomes but does increase long-term morbidity.
Implications for lymphedema risk
Lymphedema — an chronic condition characterized by swelling due to impaired lymphatic drainage — affects a substantial number of cancer survivors. In breast cancer, node removal has long been associated with elevated lymphedema risk; historically, roughly one in five women experience swelling after axillary surgery. By avoiding ALND, the trial demonstrated a clear reduction in the arm complications that drive disability and reduced quality of life.
Clinical interpretation
The lead investigators emphasized that axillary surgery should be viewed primarily as a staging or diagnostic tool rather than an essential therapeutic step for patients with limited nodal involvement. Omitting ALND when radiation is used, they argue, spares patients a major source of long-term harm without compromising disease control. This reframing affects how multidisciplinary teams weigh the benefits and harms of additional axillary interventions.
Context and outlook
Lymphedema remains an important survivorship issue: more than 200,000 people in the UK live with the condition, and up to 10 million people in the US may be affected by lymphatic disorders overall. Breast cancer is the most commonly diagnosed cancer in women in the UK, with around 59,000 new cases each year, and in the US breast cancer makes up a large share of cancer diagnoses, with projections estimating about 322,000 women diagnosed in 2026. Given these numbers, strategies that safely reduce treatment-related complications could benefit thousands of survivors.
Patient advocates and research organizations have welcomed trials that prioritize quality of life alongside survival. While the new data are promising, experts note the importance of continued research: larger trials and longer follow-up will help confirm which subgroups benefit most from omitting ALND and refine treatment guidance. In the meantime, clinicians should discuss the trade-offs of axillary surgery versus radiation with eligible patients, highlighting the potential to preserve arm function and reduce the lifetime risk of lymphedema.
What patients should ask their team
When discussing axillary management, patients may consider questions such as: How many nodes are involved? Would radiotherapy alone offer equivalent control for my situation? What are the short- and long-term side effects of each option? Clear communication between patients and multidisciplinary teams will help tailor care to individual priorities, balancing oncologic safety with functional outcomes.
