Background: By today's standard, the optimal treatment of every individual tumor patient is discussed and determined in an interdisciplinary tumor board. According to the new S3 guidelines, larger volume T3 laryngeal cancers which are no longer safely resectable with larynx-sparing surgery are ideal candidates for a larynx preservation approach using primary chemoradiation (pCRT). So far, no clear criteria have been defined under what circumstances primary radiotherapy alone (pRT) might be acceptable in case chemotherapy (CT) is prohibited or in what cases, even in T3, upfront total laryngectomy with risk-adapted adjuvant treatment (TL±a[C]RT) should be recommended., Method: The literature was searched for parameters chosen as criteria for an inclusion in the surgical rather than the conservative arm in non-randomized LP studies or which proved to be significant prognostic markers after conservative treatment. Development of a counselling tool for therapeutic decision making., Results: Significant prognostic markers were tumor volume (< 3.5 ccm/< 6 ccm vs. 6-12 ccm vs. > 12 ccm), presence and kind of vocal cord fixation (none vs. Succo I/II vs. Succo III/IV), extent of cartilage infiltration (none vs. minimal vs. multiple/gross), nodal status (N0‑1 vs. N2-3), and laryngeal dysfunction (pretreatment necessity of feeding tube or tracheostomy)., Conclusion: For T3 laryngeal cancers, pRT could be acceptable when the tumor volume is < 3.5 ccm for glottic and < 6 ccm for supraglottic tumors and there are no further risk factors. pCRT can be regarded as the standard for LP for tumors between 6 ccm and 12 ccm, vocal cord fixation Succo pattern I/II, only minimal cartilage infiltration and a high nodal burden. For tumor > 12 ccm, vocal cord fixation Succo pattern III/IV, gross or multiple cartilage infiltration or clinically relevant laryngeal dysfunction, upfront TL±a[C]RT should be considered., (© 2022. The Author(s).)