**6.2 Optimization of postsurgical rehabilitation in the context of adjuvant treatments**

After any brain surgery, even when it has not been associated with any complication, a recovery period for normal brain function is needed. Sometimes, the improvement in the neurological function appears immediately after the surgery because the de-lesion was producing a mass effect or dysfunction in the surrounding regions. However, it is relatively common that, after surgery, brain tumor patients (mainly those whose lesion is in or near eloquent regions, as those who present an indication for an awake procedure) show a worsening in some neurological functions, even when the mapping technique and the surgery have been adequately performed. In fact, a worsening in language function has been reported in 14–50% of patients, but 78–100% of patients have recovered a normal function at 1 month. Furthermore, postsurgical transitory cognitive dysfunction in 55% of patients treated with an awake procedure has been reported. This worsening is associated with the increase of edema related to surgical handling, as well as the presence of blood resting in the tumor cavity. In our experience, this worsening is normally higher in patients with high- than low-grade gliomas.

In any case, after the surgery, a recovery period must be considered in all patients, which may include the indication of simple tasks to facilitate the spontaneous recovery process or an organized rehabilitation program. This therapy would try to accelerate and/or modify brain plasticity mechanisms to make them more efficient. However, the recovery period after brain surgery may be truncated or limit their effectiveness due to the use of other oncological adjuvant treatments. More specifically, the early use of radiotherapy in low- and high-grade gliomas or brain metastasis may slow the normal process of recovery down by damaging and limiting the development of brain plasticity mechanisms. From a tumoral biology point of view, the best moment for applying radiotherapy is in the first 4–6 weeks

after the surgery. Plasticity mechanisms can develop until 8–12 weeks after surgery; thus, radiotherapy may constitute a limitation in the recovery capacity of neurooncological patients. This aspect may be considered in future studies because if the surgical aim is to achieve the maximal extent of resection but preserving the function, adjuvant treatments should not undermine what surgery has achieved. In this regard, we consider that radiotherapy should be delayed as much as possible, without limiting its effectiveness related to tumor biology. On the other hand, the rehabilitation program should start as soon as possible after the surgery, in an intensive and integrative manner. This will allow us to take advantage of the "plasticity window" after the surgery. In any case, it would be useful to identify serological or imaging neural plasticity biomarkers for a better follow-up, to decide the best moment to start the rest of the oncological treatments.
