[19]. In addition to a rapid response team, use of the Modified Early Warning Score (MEWS) or of biomarkers such as serum lactate has proven effective in enhancing prompt admission to the ICU [20]. Diagnostic strategy in patients with acute respiratory failure Acute respiratory failure (ARF) is the leading cause of ICU admission among patients with cancer [21]. As there are many possible ARF etiologies, a timely and accurate diagnostic strategy that takes into account characteristics of the underlying malignancy, the type of immune suppression, the type of respiratory symptoms, and radiological findings, as well as associated organ dysfunctions is appropriate [22, 23]. High-resolution computed tomography of the thorax provides important guidance for the choice of appropriate diagnostic tests [24]. Pleural and pulmonary echography, as well as echocardiography, are noninvasive tests with high diagnostic yield. Early fiberoptic bronchoscopy and bronchoalveolar lavage (BAL) were the cornerstones of the diagnostic workup until a multicenter randomized controlled trial (RCT) reported that management with or without BAL led to similar outcomes [10]. Surgical lung biopsy has long been considered as the gold standard for identifying ARF etiology in cancer patients with pulmonary infiltrates; however, recent findings showed that the procedure was not superior to BAL for diagnosis of infections, while still associated with higher morbidity and mortality [25]. Beside the highly variable outcomes associated with the various causes of ARF (15% mortality in cardiogenic pulmonary edema and 85% in patients with invasive aspergillosis), inability to identify ARF etiology is an independent predictor of mortality [26]. Initial oxygenation strategy for acute hypoxemic respiratory failure The literature is equivocal in terms of harm or benefit from noninvasive mechanical ventilation (NIV) in these patients. The need for invasive mechanical ventilation has been associated with mortality in numerous studies [27]. A recent trial from the Groupe de Recherche Respiratoire en Réanimation Onco-Hématologique (GRRR-OH) on early NIV in immunocompromised patients with hypoxemic ARF reported no significant benefits from NIV [28]. However, mortality has decreased significantly over the last decade [29,30,31]; it was 90% in the control group of Hilbert’s trial [32], but only 26% in both groups of Lemiale’s trial [28]. Half the patients with severe ARF and 75% of severe ARDS patients experience NIV failure with significantly higher mortality [33, 34]. Therefore, NIV may be used with caution in cancer patients with hypoxemic ARF, and should be avoided in severe hypoxemia. The five following elements strongly suggest that the literature is inconclusive and that trials are warranted: (1) early NIV does not translate anymore into survival benefits, and is maybe harmful; (2) high flow oxygen has demonstrated survival benefits as compared to NIV [35]; however, this is still controversial in cancer patients [36, 37]; (3) mortality has decreased in patients with severe ARDS and in non-ARDS patients receiving mechanical ventilation [38,39,40]. In a multicenter cohort of hematology patients admitted to 17 ICUs in France and Belgium [8], mortality among patients with ARF was 42%. (4) It is increasingly believed that NIV cannot avoid high tidal volumes being delivered to hypoxemic patients with high respiratory drives, and possible ventilator-induced lung injury and worsening of respiratory status [41]. (5) Last, most of the