OBJECTIVES:Controversy about quality-of-life (QOL) benefits of sentinel lymph node biopsy (SLNB) versus axillary lymph node dissection (ALND) in patients with breast cancer remains. Our aim was to compare the impact of SLNB and ALND on QOL and arm symptoms of patients with early breast cancer, using generic (short form 36 health survey) and tumor site-specific (FACT-B+4) instruments. METHODS:This was a prospective longitudinal observational study of 93 patients (64 SLNB, 29 ALND). Patients were evaluated presurgery and 1, 6, and 12 months postsurgery. Generalized estimation equation models were constructed to assess the effect of treatment on QOL. The relative risks of edema, dysesthesia, and heaviness were calculated comparing ALND to SLND. RESULTS:Most patients presented T1 (67.7%) and underwent breast-conserving surgery (92.5%). At 12 months, the SLNB group presented deterioration on the FACT-B+4 Arm Scale (beta coefficient estimated a change of -1.6 score points; P < 0.01) while, compared with SLNB, the deterioration in the ALND group was almost 2 additional score points higher (P = 0.009). FACT-B+4 global summary and short form 36 health survey did not show statistically significant differences between groups. Relative risk of dysesthesia and subjective edema was higher for the ALND group than for the SLNB group (1.97 and 2.11 at month 12; P < 0.01). CONCLUSION:These results confirm the benefit of SLNB due to its lower arm morbidity impact on QOL, compared with ALND. There are clinically relevant between-treatment differences in the Arm Scale of FACT-B+4, while there were no relevant differences in general well-being, measured with the disease-specific FACT-B+4 and the generic short form 36 health survey.