Intraoperative cytologic diagnosis of breast sentinel lymph nodes in the routine, nonacademic setting: a highly specific test with limited sensitivity.

Intraoperative determination of metastatic breast carcinoma in sentinel lymph nodes (SLNs) by cytologic methods has been proposed as highly specific and sensitive. Much of these data are derived from academic institutes with highly trained personnel and without axillary dissection occurring as a direct result of the intraoperative interpretation. This prospective study was undertaken to assess the sensitivity and specificity of cytology in the routine, private-practice, intraoperative setting. A total of 207 SLNs from 96 breast carcinoma patients were evaluated by intraoperative cytologic preparations by general surgical pathologists; positive results led to axillary lymphadenectomy. Ten nodes were positive by intraoperative cytology (IC). Permanent section analysis confirmed the presence of carcinoma in the IC-positive cases and documented carcinoma in 19 of the IC-negative cases. IC sensitivity and specificity were 34% and 100%, respectively. False-negative IC interpretations occurred in nodes with occult micrometastases (12 of 19 nodes) and lobular carcinoma (6 of 19 nodes). Only one of eight grossly positive sentinel nodes resulted in a false-negative IC. While near-perfect specificity and high sensitivity can be achieved with grossly positive sentinel nodes by IC, sensitivity is quite low in cases with micrometastatic and lobular carcinoma.

Interpretive disparity among pathologists in breast sentinel lymph node evaluation.

BACKGROUND: Immunohistochemical staining on breast sentinel lymph nodes (SLN) is controversial. METHODS: Twenty-five SLN cases were reviewed by 10 pathologists (three academic, seven private) including 5 negative by both hematoxylin and eosin (H&E) and immunohistochemistry, 11 micrometastases (<2 mm) negative by H&E but positive by immunohistochemistry, and 8 micrometastases and 1 macrometastasis (>2 mm) positive for both H&E and immunohistochemistry. Answers included "positive," "negative," and "indeterminate" for each slide. RESULTS: The mean number of incorrect responses was 6.6 for immunohistochemistry and 5 for H&E. Twelve percent of cases were correct by all 10 pathologists; 80% of positive IHC cases had at least one pathologist score it incorrectly. As tumor cells decrease in number, incorrect responses increase. When tumor cells numbered less than 10, more than 30% of pathologists answered incorrectly. CONCLUSIONS: As tumor cells decrease in number pathologists' ability to recognize them decreases. We propose adding "indeterminate" to "positive" and "negative" when tumor cells number less than 10.

Pilot trial of genetically modified, attenuated Salmonella expressing the E. coli cytosine deaminase gene in refractory cancer patients.

We performed a pilot trial in refractory cancer patients to investigate the feasibility of intratumoral injection of TAPET-CD, an attenuated Salmonella bacterium expressing the E. coli cytosine deaminase gene. A total of three patients received three dose levels of TAPET-CD (3 x 10(6)-3 x 10(7) CFU/m(2)) via intratumoral injection once every 28 days as long as progression of disease or intolerable toxicity was not observed. From days 4 to 14 of each 28 day cycle, patients also received 5-fluorocytosine (5-FC) at a dose of 100 mg/kg/day p.o. divided three times daily. Six cycles of treatment were administered. No significant adverse events clearly attributable to TAPET-CD were demonstrated. Two patients had intratumor evidence of bacterial colonization with TAPET-CD, which persisted for at least 15 days after initial injection. Conversion of 5-FC to 5-fluorouracil (5-FU) as a result of cytosine deaminase expression was demonstrated in these two patients. The tumor to plasma ratio of 5-FU for these two colonized patients was 3.0, demonstrating significantly increased levels of 5-FU at the site of TAPET-CD colonization and insignificant systemic spread of the bacteria. In contrast, the tumor to plasma ratio of 5-FU of the patient who did not show colonization of TAPET-CD was less than 1.0. These results support the principle that a Salmonella bacterium can be utilized as a delivery vehicle of the cytosine deaminase gene to malignant tissue and that the delivered gene is functional (i.e. able to convert 5-FC to 5-FU) at doses at or below 3 x 10(7) CFU/m(2).