Lymph node dissection plays an important role in staging and treatment of solid cancers. Sentinel node biopsy (SNB) has been introduced to minimize the extent of surgery and to enable assessment of minimal residual disease (MRD) without compromising accurate staging or survival. This review addresses the variation in technical aspects and outcome of SNB and MRD assessment in patients with breast and gastrointestinal cancer. Quality control leading to standardization of SNB and pathological examination will enable reliable comparison of studies, which is necessary for consensus of diagnostic and therapeutic strategies.