Objective: The objective of this study is to analyze the influence of tumor size and age of the patient in the detection of the SN in breast neoplasms.
Material and methods: A total of 190 patients affected of breast cancer with a mean age of 57 years (range from 28 to 87 years) were studied. According to age, the following were distinguished: under 40 years, 23 patients; between 40 and 60 years, 102 patients and over 60 years, 65 patients. The lesions were classified based on size (in mm) into: less than 10 in 27 patients, between 10 and 20 in 61 patients, between 20 and 30 in 64 patients, and greater than 30 in 38 patients. In all the cases, a scintigraphy was performed at 2 hr. post-injection of 3 mCi of 99mTc-nanocoloide, in the peritumoral area. After lymphoscintigraphy detection of the SN, cutaneous labeling was performed and it was detected surgically by a gamma detector probe. A complete lymphadenectomy was performed in all the patients. The histopathology was performed with hematoxylin-eosin and immunohistochemistry techniques and the state of the SN was compared with the remaining lymph nodes of the lymphadenectomy.
Results: The SN was located in 169 of the 190 cases (89%). In 164 cases, it was found in the axilla. The greatest percentage of those not detected was observed in tumors over 30 mm (32%) and patients older than 60 years (30%). No false negative were observed in tumors under 10 mm or in patients under 40 years, but the false negative rate increased with the patient's age and the tumor size.
Conclusions: The patient's age and tumor size seem to influence SN detection rates. The FN rates seem to be superior in patients over 60 years. Patients under 40 years with tumors less than 10 mm are those who benefit most from this technique.