We read the retrospective study of Mizbah et al. on the comparison between oral cancer patients who received endosseous dental implants in the mandibular interforaminal area, either during ablative surgery or delayed, with great interest. We underline their conclusion that patients with the implants placed during ablative surgery will benefit earlier from an implant-retained mandibular overdenture than patients for whom implant placement is delayed, but feel that such a firm conclusion cannot be drawn on the basis of their study design and the analysis provided. In fact, their primary outcome measure, that patients provided with implants during ablative surgery will be subjected to earlier prosthetic rehabilitation without an increased complication rate, is a non issue. As patients for whom implant insertion was postponed had to show a recurrence-free interval of at least 1 year and next had to be subjected to hyperbaric oxygen treatment (HBO) and a longer osseointegration interval, one could expect that most of them would not have started with implant treatment at a date the other patients, with implants placed during the ablation, had already been provided with implant-retained overdentures. Furthermore, from a radio-biological perspective, the risk of developing a higher complication rate is unlikely, as the risk of developing, for example, osteoradionecrosis, will increase with the time elapsed after radiotherapy.
In contrast to what was reported in the prospective studies of, for example, Schoen et al. and Korfage et al. , no attempt was made to rate the functional outcome and quality of life using the different treatment protocols, although much attention was paid to this issue in the discussion.
In fact two different protocols applied at different centres were compared, which makes a comparison of the results impossible. What would have been the outcome had the treatments at the two centres been reversed? The same? Or would, for example, implant survival and the number of patients wanting implants later after tumour therapy be higher or lower? Furthermore, the need for HBO is not discussed; it is just standard care at the participating centre. However, in a small prospective, randomized trial it was shown that implant survival and the rate of post-treatment complications were comparable between patients who had received hyperbaric oxygen treatment and those who had not, questioning its need.
Instead of focusing on implant survival and numbers of patients benefitting from implant-retained mandibular overdentures, this paper would gain considerably in strength if the authors analyzed on which indication it was decided to place implants during ablative surgery or not, as well as which subgroup of patients would benefit most from, and would be willing to be subjected to, delayed implant therapy. On the basis of such analyses, including data from other relevant studies, the authors could have proposed an algorithm for determining which patients should be treated during ablative surgery or should have delayed implant placement. Taking the data from their study and our studies into account, we would propose the following algorithm ( Fig. 1 ): only patients without the need or possibility for primary ablative tumour surgery, patients for whom no prosthetic problems are expected, and patients for whom implant placement during surgery is not possible should not receive primary implants. In these patients, delayed implant placement might be considered when indicated and possible. Thus, more patients will benefit from implant-retained overdentures at an earlier stage after oncological treatment, allowing them to improve their oral function as soon as possible. It would be a great asset to the literature if the authors could add to the proposed algorithm on the basis of the data they gathered for their study.
