Radio-Guided Lymph Node Mapping in Bladder Cancer Using SPECT/CT and Intraoperative γ-Probe Methods: Reply
On behalf of the whole team, I would like to thank you for the letter that we received about our published article, “Radio-Guided Lymph Node Mapping in Bladder Cancer Using SPECT/CT and Intraoperative γ-Probe Methods.”1 The aim of our study was to evaluate the possibility of lymph node (LN) mapping in case of muscle-invasive bladder cancer (MIBC), and I am very pleased that our work has been met with such recognition. We are grateful for the number of issues that have been raised in your letter. However, we cannot agree with the method of calculation that was proposed.
In our study, we examined a group of 38 patients with MIBC. In 3 patients, lack of lymphatic drainage from the tumor was observed, which resulted in the lack of detectable LNs. These patients were excluded from further analysis. In 34 patients, LNs had increased radiotracer uptake (so-called hot spots), and in 12 cases, histopathologic examination confirmed metastases in those resected nodes. Unfortunately, in 1 case, the 2 tested methods failed, whereas histopatologic examination showed presence of metastasis. That was marked as false-negative case. According to the presented results, 22 patients were classified as false-positive cases.
The experimental results presented above confirm our previous calculations. Moreover, there are a number of publications that also confirm it.2–7 Therefore, we cannot agree with neither your new classification nor calculations because they do not reflect the results received in our experiment.
However, I understand that in our article the results and the calculations might not have been explained clearly enough, and that might have caused misunderstandings.
To summarize, I would like to thank you for the interest that you put into our publication. Radioguided LN mapping technique in the case of MIBC is still a very new method, but with a huge potential. We believe that our work contributes to a better understanding of this technique.