Modeling of α/β for late rectal toxicity from a randomized phase II study: conventional versus hypofractionated scheme for localized prostate cancer

Abstract Background Recently, the use of hypo-fractionated treatment schemes for the prostate cancer has been encouraged due to the fact that α/β ratio for prostate cancer should be low. However a major concern on the use of hypofractionation is the late rectal toxicity, it is important to be able to predict the risk of toxicity for alternative treatment schemes, with the best accuracy. The main purpose of this study is to evaluate the response of rectum wall to changes in fractionation and to quantify the α/β ratio for late rectal toxicity Methods 162 patients with localized prostate cancer, treated with conformal radiotherapy, were enrolled in a phase II randomized trial. The patients were randomly assigned to 80 Gy in 40 fractions over 8 weeks (arm A) or 62 Gy in 20 fractions over 5 weeks (arm B). The median follow-up was 30 months. The late rectal toxicity was evaluated using the Radiation Therapy Oncology Group (RTOG) scale. It was assumed ≥ Grade 2 (G2) toxicity incidence as primary end point. Fit of toxicity incidence by the Lyman-Burman-Kutcher (LKB) model was performed. Results The crude incidence of late rectal toxicity ≥ G2 was 14% and 12% for the standard arm and the hypofractionated arm, respectively. The crude incidence of late rectal toxicity ≥ G2 was 14.0% and 12.3% for the arm A and B, respectively. For the arm A, volumes receiving ≥ 50 Gy (V50) and 70 Gy (V70) were 38.3 ± 7.5% and 23.4 ± 5.5%; for arm B, V38 and V54 were 40.9 ± 6.8% and 24.5 ± 4.4%. An α/β ratio for late rectal toxicity very close to 3 Gy was found. Conclusion The ≥ G2 late toxicities in both arms were comparable, indicating the feasibility of hypofractionated regimes in prostate cancer. An α/β ratio for late rectal toxicity very close to 3 Gy was found.</p

Towards a collaborative approach to the systematics of Ipomoea: A response to the “Rebuttal to (2786) Proposal to change the conserved type of Ipomoea, nom. cons. (Convolvulaceae)”.

A proposal to change the conserved type of was published in December 2020, and recommended by the Nomenclature Committee in 2023. This was done in the light of the possible negative consequences for a name change in the crop sweetpotato, which risk our proposal would significantly minimize. Recently, Muñoz‐Rodríguez &amp; al. have published a rebuttal to this proposal, which we respond to here. The objections raised by these authors focus as much on the expertise and credibility of our group of authors as on the merits of our arguments. In this “rebuttal to the rebuttal”, we respond to the scientific questions raised, highlight demonstrated misinterpretation of the specialised literature relevant to this discussion and counter the assertion that a reclassification of Ipomoeeae is impossible given existing evidence. While the currently recognised genera of Ipomoeeae are not all monophyletic, the proposal to change the conserved type of is a necessary step that will allow exploring an improved classification for the tribe Ipomoeeae, either in the form of a better recircumscription of the genera or an efficient infrageneric classification for . Previously published literature has not advocated for the integration of all genera into a single genus, as Muñoz‐Rodríguez and co‐authors have incorrectly suggested, and instead have recommended a reanalysis of the high morphological diversity of the group in the context of expanded phylogenetic studies, with the possible maintenance of some of the existing genera. We believe that, in a concerted collaborative approach and with the contribution of experts from different regions and scientific backgrounds, an improved classification of Ipomoeeae that integrates the principles of monophyly and diagnosability may soon be achieved, and until when some uncertainty may need to be accommodated, with the added reassurance that, regardless of the direction of future systematic rearrangements, the stability of the scientific name of sweetpotato would be preserved

The sacral chordoma margin

Objective Aim of the manuscript is to discuss how to improve margins in sacral chordoma. Background Chordoma is a rare neoplasm, arising in half cases from the sacrum, with reported local failure in >50% after surgery. Methods A multidisciplinary meeting of the “Chordoma Global Consensus Group” was held in Milan in 2017, focusing on challenges in defining and achieving optimal margins in chordoma with respect to surgery, definitive particle radiation therapy (RT) and medical therapies. This review aims to report on the outcome of the consensus meeting and to provide a summary of the most recent evidence in this field. Possible new ways forward, including on-going international clinical studies, are discussed. Results En-bloc tumor-sacrum resection is the cornerstone of treatment of primary sacral chordoma, aiming to achieve negative microscopic margins. Radical definitive particle therapy seems to offer a similar outcome compared to surgery, although confirmation in comparative trials is lacking; besides there is still a certain degree of technical variability across institutions, corresponding to different fields of treatment and different tumor coverage. To address some of these questions, a prospective, randomized international study comparing surgery versus definitive high-dose RT is ongoing. Available data do not support the routine use of any medical therapy as (neo)adjuvant/cytoreductive treatment. Conclusion Given the significant influence of margins status on local control in patients with primary localized sacral chordoma, the clear definition of adequate margins and a standard local approach across institutions for both surgery and particle RT is vital for improving the management of these patients