Important data about anaesthetics and cancer recurrence

We have read with great interest the review of Votta-Velis et al. recently published in the journal.1 This unsystematic review merits its reading. Nevertheless, some errors and incompleteness could be corrected to improve the reader's comprehension. First, the authors reproduced, in table 1, our table initially published in 2009.2 This table is proposed, in the text, to summarise ‘in vitro’ studies, whereas in fact, this concerns only ‘in vivo’ studies (see our original paper). Moreover, there are inversions, in the table, of the subtitles ‘operated’ and ‘non-operated’ in each column. The inversion between ‘operated’ and ‘non-operated’ subtitles is important because anaesthetics seem to have a rather depressive effect on cellular-mediated activity [here, the Natural Killer (NK) activity] if administered in non-surgical settings. This is in contrast with a rather protective action of anaesthetics on NK activity if administered before surgery. The interpretation of the table is therefore completely different with the correctly placed subtitles. A second important thing, in our opinion, is in the paragraph ‘Retrospective studies’. The authors selected the studies seeming the most important in the analysis of the possible effect of regional anaesthesia on cancer recurrences. It may be interesting for the reader to know that in the case of prostate cancer surgery, if the authors present two studies totalising 324 patients (one positive and one proposed as unconclusive), we published in 2011 a negative study concerning 1111 prostate cancer patients.3 As the authors proposed, in the same review, that a study is with 503 patients is large, it would be interesting for the reader to know that our large series (the largest on this topic, i.e. recurrence-free survival in prostate cancer), of quality at least comparable with those selected by the authors, was clearly negative. This would complete interestingly the data presented. In conclusion, some data presented by Votta-Velis et al. are important but could be completed to correct some errors and incompleteness.