Reply

Abstract

To the Editors: The article cited by Narducci et al is different in design than the reported results from our work. The animal model as published by Narducci et al was a higher inoculum of tumor cells that were allowed to grow until the animals died from carcinomatosis. The authors showed that the time of death was not significantly different. Not surprisingly, there was no difference in effect because all the animals will eventually die from carcinomatosis with a high inoculum and enough time. This is a different animal model than the one used in our report. Our animal model is a model designed to simulate a ruptured ovary with a very small inoculum of tumor. In our study, the control animals not subjected to any surgical manipulation would only develop a small tumor implant at the intra-abdominal site of inoculation when killed at 2 weeks. When we used a higher dose of tumor cells and waited for 3 to 4 weeks, almost all animals had extensive carcinomatosis. Thus, we arrived at the lower inoculum and the time of sacrifice to not allow extensive tumor growth.By using this model, we found that carbon dioxide gas compared with laparotomy significantly increased the rate of intra-abdominal tumor spread, and the follow-up study recently showed that there was no difference in the spread when comparing the various gases. This study was done because some authors believe it is the carbon dioxide gas that influences the spread and that helium or nitrous oxide gas would be acceptable alternatives. In our work we did not find that the type of gas influences spread but carbon dioxide gas does increase the rate of spread compared with laparotomy alone. To the Editors: The article cited by Narducci et al is different in design than the reported results from our work. The animal model as published by Narducci et al was a higher inoculum of tumor cells that were allowed to grow until the animals died from carcinomatosis. The authors showed that the time of death was not significantly different. Not surprisingly, there was no difference in effect because all the animals will eventually die from carcinomatosis with a high inoculum and enough time. This is a different animal model than the one used in our report. Our animal model is a model designed to simulate a ruptured ovary with a very small inoculum of tumor. In our study, the control animals not subjected to any surgical manipulation would only develop a small tumor implant at the intra-abdominal site of inoculation when killed at 2 weeks. When we used a higher dose of tumor cells and waited for 3 to 4 weeks, almost all animals had extensive carcinomatosis. Thus, we arrived at the lower inoculum and the time of sacrifice to not allow extensive tumor growth. By using this model, we found that carbon dioxide gas compared with laparotomy significantly increased the rate of intra-abdominal tumor spread, and the follow-up study recently showed that there was no difference in the spread when comparing the various gases. This study was done because some authors believe it is the carbon dioxide gas that influences the spread and that helium or nitrous oxide gas would be acceptable alternatives. In our work we did not find that the type of gas influences spread but carbon dioxide gas does increase the rate of spread compared with laparotomy alone.