Rapid flow carbon dioxide laparoscopy disperses cancer cells into the peritoneal cavity but not the port sites in a new rat model.

BACKGROUND: The role of carbon dioxide (CO2) in the pathogenesis of tumor recurrence after laparoscopy remains controversial. Using a new rat model, we studied the effect of different CO2 flow rates on the dispersal of free cancer cells. METHODS: A novel model of desufflation without trocar was developed, and 55 Fischer rats were randomized into three flow groups: group A (rapid, 0.67 l/min; n = 20), group B (slow, 0.44 l/min; n = 20), and group C (gasless, n = 15). We vented CO2 via a portless surgical valve that filtered cells. After the abdominal wall had been suspended to create space, half of the animals in each group (nonrecovery) received 7.5 x 10(6) immunolabeled rat colon cancer cells (RCC2) intraperitoneally, whereas the other half (recovery) received 7.5 x l0(6) viable RCC2 before insufflation or gasless laparoscopy. Nonrecovery animals were killed after 20 l of insufflation. Parietal peritoneal and port-site specimens were examined for RCC2 by fluorescence microscopy (FM) and flow cytometry (FC). The recovery animals were killed at 4 weeks for evidence of wound recurrence. RESULTS: Nine of 10 nonrecovery animals in A had RCC2 on FM or FC, as compared with 2 animals in each of the nonrecovery groups B and C (p = 0.018, Fisher's exact test). Two of the nine animals in group A also had RCC2 in their portless valves. Two recovery (A) animals developed wound recurrence as compared with none in the other groups (p = 0.315). CONCLUSION: In this model, rapid CO2 flow dispersed free cancer cells into the peritoneal cavity, but not into the port sites, thus supporting a role for CO2 in the intraperitoneal dispersal of free cancer cells, but not in wound recurrence.

Oestrogen and progesterone receptor assessment in core biopsy specimens of breast carcinoma.

AIMS: To assess the suitability of core biopsy specimens for the immunohistological assessment of oestrogen and progesterone receptors in breast carcinoma. METHODS: Thirty consecutive cases of clinically palpable breast carcinoma, from which both core and excision biopsy specimens were available, were examined. Routinely processed paraffin wax sections were stained using the specific monoclonal antibodies 1D5 (Dako) for oestrogen receptor and NCL-PGR (Novocastra) for progesterone receptor, after an antigen retrieval step using a pressure cooker. Staining results were assessed using the H score system with the results being expressed as negative, weakly positive, moderately positive or strongly positive. RESULTS: Twenty six biopsy specimens contained enough tumour tissue for assessment. Absolute agreement between scoring categories was seen in 19 (73%) cases for oestrogen receptors. However, when all positive categories were added together, agreement between core and excision biopsy specimens increased to 93% (24 cases). Disagreement was seen only in two cases which stained positive in the core biopsy specimens and negative in the excision biopsy specimens. For progesterone receptors, the absolute agreement between all scoring categories was seen only in 11 (42%) cases. When all positive categories were considered together, agreement increased to 69% (18 cases). Five cases were progesterone receptor positive in core but not in excisional biopsy specimens, while three cases were negative in core but positive in excisional biopsy specimens. CONCLUSIONS: The results suggest that core biopsy specimens can be reliably used for oestrogen receptor assessment, but are less reliable for progesterone receptor assessment, probably because of a greater heterogeneity of progesterone receptor staining.