PD30 Radioactive Seed Localization And Radio-Guided Occult Lesion Localization For Non-Palpable Breast Cancer Surgery: A Meta-Analysis

Introduction Non-palpable breast cancers require intraoperative localization to guide the surgical procedure. The radio-guided occult lesion localization (ROLL) and radioactive seed localization (RSL) techniques use radioactive material (technetium-99m labeled macroaggregated albumin and iodine-125 seeds, respectively) implanted at the lesion site. The success of conservative surgery depends on complete tumor excision with negative surgical margins. The objective of this study was to perform a meta-analysis of the surgical effectiveness of the ROLL and RSL techniques with respect to rates of positive surgical margins, reoperation, and recurrence. Methods A systematic search of the PubMed, Embase, LILACS, SciELO, and Web of Science databases was performed on 2 August 2021. A standard form was used to extract data from the studies selected in the screening process. The ROBINS-I tool was used to analyze risk of bias and RevMan 5.4 software was used to perform the meta-analysis. Results Four observational studies met the inclusion criteria. The overall evidence quality was moderate. The studies included women aged from 28 to 91 years with non-palpable breast cancer. The results demonstrated similar effectiveness between RSL and ROLL for rates of positive surgical margins (risk ratio [RR] 0.83, 95% confidence interval [CI]: 0.50, 1.39; 763 patients) and reoperation (RR 1.14, 95% CI: 0.75, 1.74; 1,550 patients). Regarding the rate of disease recurrence, RSL was superior to ROLL (RR 0.50, 95% CI: 0.29, 0.87; 939 patients). Conclusions The results demonstrate that the ROLL and RSL techniques are equivalent with respect to rates of positive surgical margins and reoperation, although patients undergoing RSL had lower rates of disease recurrence. However, there is a tendency to favor the RSL technique because of the longer interval between implantation and surgery, which is possible due to the longer half-life of iodine-125 (59.4 days). This also means that radioactive seed implantation can occur before neoadjuvant chemotherapy, so the tumor bed remains marked if further interventions are required, obviating the need for another invasive procedure before surgery.