[Intraoperative detection of sentinel lymph nodes in cutaneous malignant melanoma -- blue dye alone versus blue dye plus gamma detection].

BACKGROUND: Compared with intraoperative sentinel lymph node identification using blue dye only, the introduction of a hand-held gamma probe has improved the identification rates. In this retrospective study, further aspects related to the introduction of gamma-guided preparation are analysed in detail. PATIENTS AND METHODS: 81 patients who underwent sentinel biopsy using the blue dye technique were compared to 247 patients whose operations were guided by blue dye and gamma probe. RESULTS: After the introduction of radio-guided surgery, the sentinel node identification rate increased from 87.7 % to 99.2 % (P < 0.00001). The number of harvested sentinel lymph nodes increased from 1.4 +/- 0.9 to 1.8 +/- 0.09 (P < 0.00001). The "clinical false-negative rate" decreased from 15.8 % to 9.6 %. The percentage of positive completion lymphadenectomy decreased from 50 % to 24.6 %. The risk of postoperative seroma decreased as a consequence of gamma guided preparation (5.1 % versus 15 %, P = 0.01). Regarding overall survival and recurrence-free survival, there were no significant differences between both groups. The 5-year-probability of nodal basin failure was 7.9 % after negative sentinel biopsy and 25.3 % after positive sentinel lymphonodectomy plus consecutive completion lymphadenectomy. CONCLUSIONS: Combined application of blue dye and gamma-probe improved sensitivity and decreased the risk of postoperative seroma. The probability of recurrence and survival was not influenced by the technique of intraoperative sentinel node identification.