Proton pencil beam scanning radiotherapy in the postoperative treatment of p16 positive squamous cell tonsillar cancer - evaluation of toxicity and effectivity.

PURPOSE: Patients with p16 positive tonsillar cancer (p16 + TC) have an excellent prognosis and long-life expectancy. Deintensification of therapy is a prevalent topic of discussion. Proton radiotherapy is one way to reduce radiation exposure and thus reduce acute and late toxicity. The aim is to evaluate treatment outcomes and toxicity of postoperative treatment with intensity-modulated proton therapy (IMPT). METHODS: Between September 2013 and November 2021, 47 patients with p16 + TC were treated postoperatively with IMPT. Median age was 54.9 (38.2-74.9) years, 31 were males and 16 were females. All patients had squamous cell carcinoma and underwent surgery as a primary treatment. Median dose of radiotherapy was 66 GyE in 33 fractions. Bilateral neck irradiation was used in 39 patients and unilateral in 8. Concomitant chemotherapy was applied in 24 patients. RESULTS: Median follow-up time was 4.2 (0.15-9.64) years. Five-year overall survival, relapse free survival and local control were 95.7%, 97.8% and 100%. The most common acute toxicities were dermatitis and mucositis, with grade 2 + in 61.7% and 70.2% of patients. No acute percutaneous gastrostomy insertion was necessary and intravenous rehydration was used in 12.8% of patients. The most common late toxicity was grade 1 xerostomia in 70.2% of patients and grade 2 in 10.6% of patients. Subcutaneous fibrosis of grades 2 and 3 occurred in 17.0% and 2.1% of patients, respectively. One patient developed late severe dysphagia and became PEG-dependent. CONCLUSION: IMPT for the postoperative treatment of p16 + TC is feasible with excellent efficiency and acceptable acute and late toxicity.

5-Years Analysis of Effectivity and Toxicity of Ultra-Hypofractionated Proton Radiotherapy in the Treatment of Low- and Intermediate-Risk Prostate Cancer-A Retrospective Analysis.

BACKGROUND: We retrospectively analyzed the 5-year biochemical disease-free survival (bDFS) and occurrence of late toxicity in prostate cancer patients treated with pencil beam scanning (PBS) proton radiotherapy. METHODOLOGY: In the period from January 2013 to June 2018, 853 patients with prostate cancer were treated with an ultra-hypofractionated schedule (36.25 GyE/five fractions). The mean PSA value was 6.7 (0.7-19.7) µg/L. There were 318 (37.3%), 314 (36.8%), and 221 (25.9%) patients at low (LR), favorable intermediate (F-IR), and unfavorable intermediate risk (U-IR), respectively. Neoadjuvant hormonal therapy was administered to 197 (23.1%) patients, and 7 (0.8%) patients had adjuvant hormonal therapy. The whole group of patients reached median follow-up time at 62.7 months, and their mean age was 64.8 (40.0-85.7) years. The bDFS rates and late toxicity profile were evaluated. RESULTS: Median treatment time was 10 (7-38) days. Estimated 5-year bDFS rates were 96.5%, 93.7%, and 91.2% for low-, favorable intermediate-, and unfavorable intermediate-risk groups, respectively. Cumulative late toxicity (CTCAE v4.0) of G2+ was as follows: gastrointestinal (GI)-G2: 9.1%; G3: 0.5%; genitourinary (GU)-G2: 4.3%, and no G3 toxicity was observed. PSA relapse was observed in 58 (6.8%) patients: 16 local, 22 lymph node, 4 bone recurrences, and 10 combined sites of relapse were detected. Throughout the follow-up period, 40 patients (4.7%) died, though none due to prostate cancer. CONCLUSION: Ultra-hypofractionated proton beam radiotherapy is an effective treatment for low- and favorable intermediate-risk prostate cancer, with long-term bDFS rates comparable to other techniques. It is promising for unfavorable intermediate-risk prostate cancer and has acceptable long-term GI and favorable GU toxicity.

Pencil-beam scanning proton therapy for the treatment of glomus jugulare tumours.

INTRODUCTION: Glomus jugulare tumours (GJT) are benign tumours that arise locally and destructively in the base of the skull and can be successfully treated with radiotherapy. Patients have a long-life expectancy and the late effects of radiotherapy can be serious. Proton radiotherapy reduces doses to critical organs and can reduce late side effects of radiotherapy. The aim of this study was to report feasibility and early clinical results of 12 patients treated using proton therapy. METHODS: Between December 2013 and June 2019, 12 patients (pts) with GJT (median volume 20.4 cm3 ; range 8.5-41 cm3 ) were treated with intensity modulated proton therapy (IMPT). Median dose was 54 GyE (Gray Equivalents) (50-60 GyE) with daily fractions of 2 GyE. Twelve patients were analysed with a median follow-up time of 42.2 months (11.3-86.7). Feasibility, dosimetric parameters, acute and late toxicity and local effect on tumour were evaluated in this retrospective study. RESULTS: All patients finished treatment without interruption, with excellent dosimetric parameters and mild acute toxicity. Stabilisation of tumour size was detected on MRI in all patients. No changes in symptoms were observed in comparison with pre-treatment conditions. No late effects of radiotherapy were observed. CONCLUSION: Pencil-beam scanning proton radiotherapy is highly feasible in the treatment of large GJT with mild acute toxicity and promising short-term results. Longer follow-up and larger patient cohorts are required to further identify the role of pencil-beam scanning (PBS) for this indication.

Ultrahypofractionated Proton Radiation Therapy in the Treatment of Low and Intermediate-Risk Prostate Cancer-5-Year Outcomes.

PURPOSE: To analyze the 5-year biochemical disease-free survival (bDFS) and late toxicity profile in patients with prostate cancer treated with pencil beam scanning (PBS) proton radiation therapy. METHODS AND MATERIALS: Between January 2013 and March 2016, 284 patients with prostate cancer were treated using intensity modulated proton therapy (IMPT), with an ultrahypofractionated schedule (36.25 GyE in 5 fractions). Five patients were immediately lost from follow-up and thus were excluded from analysis. Data for 279 patients were prospectively collected and analyzed with a median follow-up time of 56.5 (range, 3.4-87.5) months. The mean age at time of treatment was 64.5 (40.1-85.7) years, and the median prostate-specific antigen (PSA) value was 6.35 µg/L (0.67-17.3 µg/L). A total of 121 (43.4%) patients had low-risk, 125 patients (44.8%) had favorable, and 33 (11.8%) unfavorable intermediate-risk cancer. In addition, 49 (17.6%) patients underwent neoadjuvant hormonal therapy, and no patients had adjuvant hormonal therapy. bDFS and late toxicity profiles were evaluated. RESULTS: The median treatment time was 9 days (range, 7-18 days). The 5-year bDFS was 96.9%, 91.7%, and 83.5% for the low-, favorable, and unfavorable intermediate-risk group, respectively. Late toxicity (Common Terminology Criteria for Adverse Events v.4) was as follows: gastrointestinal: grade 1, 62 patients (22%), grade 2, 20 patients (7.2%), and grade 3, 1 patient (0.36%); genitourinary: grade 1, 80 patients (28.7%), grade 2, 14 patients (5%), and grade 3, 0 patients. PSA relapse was observed in 17 patients (6.1%), and lymph node or bone recurrence was detected in 11 patients. Four (1.4%) local recurrences were detected. Nine patients (3.2%) died of causes unrelated to prostate cancer. No deaths related to prostate cancer were reported. CONCLUSION: Ultrahypofractionated proton beam radiation therapy for prostate cancer is effective with long-term bDFS comparable with other fractionation schedules and with minimal serious long-term GI and GU toxicity.

Extreme hypofractionated proton radiotherapy for prostate cancer using pencil beam scanning: Dosimetry, acute toxicity and preliminary results.

INTRODUCTION: Extreme hypofractionated radiotherapy for prostate cancer is a common modality in photon therapy. Pencil beam scanning (PBS) in similar fractionation allows better dose distribution and makes proton therapy more available for such patients. The purpose of this study is the feasibility of extreme proton hypofractionated radiotherapy and publication of early clinical results. METHODS: Two hundred patients with early-stage prostate cancer were treated with IMPT (intensity-modulated proton therapy), extreme hypofractionated schedule (36.25 GyE in five fractions) between February 2013 and December 2015. Mean age of the patients was 64.3 years, and the mean value of prostate-specific antigen (PSA) before treatment was 6.83 µg/L (0.6-17.3 µg/L). Ninety-three patients (46.5%) were in the low-risk group. One hundred and seven patients (53.5%) were in the intermediate-risk group. Twenty-nine patients (14.5%) had neoadjuvant hormonal therapy, and no patients had adjuvant hormonal therapy. Acute toxicity, late toxicity and short-term results were evaluated. RESULTS: All patients finished radiotherapy without interruptions. The median follow-up time was 36 months. The mean treatment time was 9.5 days (median 9 days). Acute toxicity according to Common Terminology Criteria for Adverse Events (CTCAE) v 4.0 was (gastrointestinal toxicity) GI (grade) G1-17%, G2-3.5%; (genitourinary toxicity) GU G1-40%, G2-19%; and no G3 toxicity was observed. Late toxicity was GI G1-19%, G2-5.5%; GU G1-17%, G2-4%; and no G3 toxicity was observed. PSA relapse was observed in one patient (1.08%) in the low-risk group (pelvic lymph node involvement was detected) and in seven patients (6.5%) in the intermediate-risk group (three lymph node metastases, two lymph node and bone metastases, two PSA relapses). No patient died of prostate cancer, and three patients died from other reasons. No local recurrence of cancer in the prostate was observed. CONCLUSIONS: Proton beam radiotherapy for prostate cancer is feasible with a low rate of acute toxicity and promising late toxicity and effectivity.

An autophagy-associated Atg8 protein is involved in the responses of Arabidopsis seedlings to hormonal controls and abiotic stresses.

Eukaryotes contain a ubiquitous family of autophagy-associated Atg8 proteins. In animal cells, these proteins have multiple functions associated with growth, cancer, and degenerative diseases, but their functions in plants are still largely unknown. To search for novel functions of Atg8 in plants, the present report tested the effect of expression of a recombinant AtAtg8 protein, fused at its N-terminus to green fluorescent protein (GFP) and at its C-terminus to the haemagglutinin epitope tag, on the response of Arabidopsis thaliana plants to the hormones cytokinin and auxin as well as to salt and osmotic stresses. Expression of this AtAtg8 fusion protein modulates the effect of cytokinin on root architecture. Moreover, expression of this fusion protein also reduces shoot anthocyanin accumulation in response to cytokinin feeding to the roots, implying the participation of AtAtg8 in cytokinin-regulated root-shoot communication. External application of cytokinin leads to the formation of novel GFP-AtAtg8-containing structures in cells located in the vicinity of the root vascular system, which are clearly distinct in size and dynamic movement from the GFP-AtAtg8-containing autophagosome-resembling structures that were observed in root epidermis cells. Expression of the AtAtg8 fusion construct also renders the plants more sensitive to a mild salt stress and to a lesser extent to a mild osmotic stress. This sensitivity is also associated with various changes in the root architecture, which are morphologically distinct from those observed in response to cytokinin. The results imply multiple functions for AtAtg8 in different root tissues that may also be regulated by different mechanisms.

Homologous and heterologous reconstitution of Golgi to chloroplast transport and protein import into the complex chloroplasts of Euglena.

Euglena complex chloroplasts evolved through secondary endosymbiosis between a phagotrophic trypanosome host and eukaryotic algal endosymbiont. Cytoplasmically synthesized chloroplast proteins are transported in vesicles as integral membrane proteins from the ER to the Golgi apparatus to the Euglena chloroplast. Euglena chloroplast preprotein pre-sequences contain a functional N-terminal ER-targeting signal peptide and a domain having characteristics of a higher plant chloroplast targeting transit peptide, which contains a hydrophobic stop-transfer membrane anchor sequence that anchors the precursor in the vesicle membrane. Pulse-chase subcellular fractionation studies showed that (35)S-labeled precursor to the light harvesting chlorophyll a/b binding protein accumulated in the Golgi apparatus of Euglena incubated at 15 degrees C and transport to the chloroplast resumed after transfer to 26 degrees C. Transport of the (35)S-labeled precursor to the chlorophyll a/b binding protein from Euglena Golgi membranes to Euglena chloroplasts and import into chloroplasts was reconstituted using Golgi membranes isolated from 15 degrees C cells returned to 26 degrees C. Transport was dependent upon extra- and intrachloroplast ATP and GTP hydrolysis. Golgi to chloroplast transport was not inhibited by N-ethylmaleimide indicating that fusion of Golgi vesicles to the chloroplast envelope does not require N-ethylmaleimide-sensitive factor (NSF). This suggests that N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) are not utilized in the targeting fusion reaction. The Euglena precursor to the chloroplast-localized small subunit of ribulose-1,5-bisphosphate carboxylase was not imported into isolated pea chloroplasts. A precursor with the N-terminal signal peptide deleted was imported, indicating that the Euglena pre-sequence has a transit peptide that functions in pea chloroplasts. A precursor to the small subunit of ribulose-1,5-bisphosphate carboxylase with the hydrophobic membrane anchor and the pre-sequence region C-terminal to the hydrophobic membrane anchor deleted was imported localizing the functional transit peptide to the Euglena pre-sequence region between the signal peptidase cleavage site and the hydrophobic membrane anchor. The Euglena precursor to the small subunit of ribulose-1,5-bisphosphate carboxylase and the deletion constructs were not post-translationally imported into isolated Euglena chloroplasts indicating that vesicular transport is the obligate import mechanism. Taken together, these studies suggest that protein import into complex Euglena chloroplasts evolved by developing a novel vesicle fusion targeting system to link the host secretory system to the transit peptide-dependent chloroplast protein import system of the endosymbiont.