The Role of Carbon Ion Therapy in the Changing Oncology Landscape-A Narrative Review of the Literature and the Decade of Carbon Ion Experience at the Italian National Center for Oncological Hadrontherapy

BACKGROUND

Currently, 13 Asian and European facilities deliver carbon ion radiotherapy (CIRT) for preclinical and clinical activity, and, to date, 55 clinical studies including CIRT for adult and paediatric solid neoplasms have been registered. The National Center for Oncological Hadrontherapy (CNAO) is the only Italian facility able to accelerate both protons and carbon ions for oncological treatment and research.

METHODS

To summarise and critically evaluate state-of-the-art knowledge on the application of carbon ion radiotherapy in oncological settings, the authors conducted a literature search till December 2022 in the following electronic databases: PubMed, Web of Science, MEDLINE, Google Scholar, and Cochrane. The results of 68 studies are reported using a narrative approach, highlighting CNAO's clinical activity over the last 10 years of CIRT.

RESULTS

The ballistic and radiobiological hallmarks of CIRT make it an effective option in several rare, radioresistant, and difficult-to-treat tumours. CNAO has made a significant contribution to the advancement of knowledge on CIRT delivery in selected tumour types.

CONCLUSIONS

After an initial ramp-up period, CNAO has progressively honed its clinical, technical, and dosimetric skills. Growing engagement with national and international networks and research groups for complex cancers has led to increasingly targeted patient selection for CIRT and lowered barriers to facility access.

Preoperative Carbon Ion Radiotherapy (CIRT) with Chemotherapy in Resectable and Borderline Resectable Pancreatic Adenocarcinoma (PCa): A Multicenter Prospective Phase II Clinical Study (Pioppo Study NCT 03822936)

PURPOSE/OBJECTIVE(S)

Preoperative chemoradiation and surgery may improve survival for resectable (Re) or borderline resectable (BRe) PCa. However, there is a lack of evidence regarding the feasibility of combined chemotherapy (CT) and CIRT in the neoadjuvant setting for Re/BRe PCa, especially in the Caucasian population. To assess the safety and efficacy of this challenging combination, we designed a prospective multicentric single-arm phase II trial MATERIALS/METHODS: PIOPPO trial was opened in September 2014. We prospectively treated patients with Re/BRe Pca with a neoadjuvant CT (3 cycles of FOLFIRINOX) and a short-course of CIRT (38.4 GyRBE, 8 fractions, 4 fractions per week) planned with 4D-imaging and delivered with breath-gating and rescanning. Four-6 weeks after CIRT patients (pts) received surgery followed by adjuvant-CT (FOLFIRINOX for 9 or gemcitabine for 6 cycles). After each step patients underwent a re-staging. The primary endpoint was Local Progression Free Survival (LPFS).

RESULTS

Fourteen (47%) of the foreseen 30 pts were evaluated for enrollment. There were 4 screening failures for duodenum infiltration. Ten Caucasian pts (M = 7; 70%; F = 3;30%) with a median age of 65.5 (range:46-76) started the treatment. There were four (40%) Re and 6 (60%) BRe Pca. 100% of the Re and 50% of BRe PCa completed the planned combined treatment for a total of 7 (70%) pts. Three (30%) pts developed systemic progression after CT and underwent palliative care (2 cases) or a second line of CT (1 case). With regards to toxicities, we recorded 2 (28.6%) cases of neutropenia during CT, none acute CIRT toxicity and one (14%) case of intra-operative ulceration of the gastro-enteric anastomosis. Moreover, we reported one (14%) case of fatal liver failure due to portal vein stenosis due to the combo approach (CT+CIRT+surgery). Six (86%) pts experienced Tumor Regression Grade (TRG) = 2 according to the College of American Pathologists (CAP) and 1 (14%) a TRG = 3. At the last follow-up, among pts who completed the scheme, 2 (28%) are currently alive and disease-free at 57 and 49 months, respectively. With a median follow-up of 13 months, the median LPFS was 9.4 months (range:4.9-57), with 1 case (14%) of systemic progression and 3 cases (43%) of local recurrence + systemic progression. The study was early closed due to low accrual in August 2022.

CONCLUSION

Although the small sample size limits the interpretation of the endpoints, a neoadjuvant approach combining CT and a short course of CIRT for resectable/borderline Pca seems feasible. Liver toxicity was similar to the Japanese series and needs to deepen investigation on the vascular dose constraints and surgical techniques. Considering the worse outcomes, a better selection of patients to treat also with a centralized imaging interpretation is mandatory.

In Vitro Effects of Photon Beam and Carbon Ion Radiotherapy on the Perineural Invasion of Two Cell Lines of Neurotropic Tumours

Primary mucosal melanoma (PMM) and pancreatic ductal adenocarcinoma (PDAC) are two aggressive malignancies, characterized by intrinsic radio-chemoresistance and neurotropism, a histological feature resulting in frequent perineural invasion (PNI), supported by neurotrophic factors secreted in the tumour microenvironment (TME), such as neurotrophin-3 (NT-3). Carbon-ion radiotherapy (CIRT) could represent an effective option in unresectable PMM and PDAC. Only a few data about the effects of CIRT on PNI in relation to NT-3 are available in the literature, despite the numerous pieces of evidence revealing the peculiar effects of this type of radiation on tumour cell migration. This in vitro study investigated for the first time the response of PMM and PDAC cells to NT-3 and evaluated the effects of conventional photon beam radiotherapy (XRT) and CIRT on cell viability, proliferation, and migration. Our results demonstrated the greater capacity of C-ions to generally decrease cell viability, proliferation, and migration, while the addition of NT-3 after both types of irradiation determined an increase in these features, maintaining a dose-dependent trend and acting more effectively as a chemoattractant than inductor in the case of migration.

Proton Therapy, Magnetic Nanoparticles and Hyperthermia as Combined Treatment for Pancreatic BxPC3 Tumor Cells

We present an investigation of the effects on BxPC3 pancreatic cancer cells of proton therapy combined with hyperthermia, assisted by magnetic fluid hyperthermia performed with the use of magnetic nanoparticles. The cells' response to the combined treatment has been evaluated by means of the clonogenic survival assay and the estimation of DNA Double Strand Breaks (DSBs). The Reactive Oxygen Species (ROS) production, the tumor cell invasion and the cell cycle variations have also been studied. The experimental results have shown that the combination of proton therapy, MNPs administration and hyperthermia gives a clonogenic survival that is much smaller than the single irradiation treatment at all doses, thus suggesting a new effective combined therapy for the pancreatic tumor. Importantly, the effect of the therapies used here is synergistic. Moreover, after proton irradiation, the hyperthermia treatment was able to increase the number of DSBs, even though just at 6 h after the treatment. Noticeably, the magnetic nanoparticles' presence induces radiosensitization effects, and hyperthermia increases the production of ROS, which contributes to cytotoxic cellular effects and to a wide variety of lesions including DNA damage. The present study indicates a new way for clinical translation of combined therapies, also in the vision of an increasing number of hospitals that will use the proton therapy technique in the near future for different kinds of radio-resistant cancers.

Immune checkpoint inhibitors and Carbon iON radiotherapy In solid Cancers with stable disease (ICONIC)

ICONIC is a multicenter, open-label, nonrandomized phase II clinical trial aiming to assess the feasibility and clinical activity of the addition of carbon ion radiotherapy to immune checkpoint inhibitors in cancer patients who have obtained disease stability with pembrolizumab administered as per standard-of-care. The primary end point is objective response rate, and the secondary end points are safety, survival and disease control rate. Translational research is an exploratory aim. The planned sample size is 27 patients. The study combination will be considered worth investigating if at least four objective responses are observed. If the null hypothesis is rejected, ICONIC will be the first proof of concept of the feasibility and clinical activity of the addition of carbon ion radiotherapy to immune checkpoint inhibitors in oncology.

Factors released by low and high-LET irradiated fibroblasts modulate migration and invasiveness of pancreatic cancer cells

Introduction

Radiotherapy represents a major treatment option for patients with pancreatic cancer, however, its benefits remain limited also due to the ability of cancer cells to migrate to the surrounding tissues. Low-LET ionizing radiation is well known to promote tumor cell migration and invasion, nevertheless, little data provided by studies using high-LET radiation has led to ambiguous findings. What is hypothesized to be fundamental in the modulation of migration of tumor cells exposed to ionizing radiation is the influence of the microenvironment. Therefore, the properties of cells that populate the tumor stroma cannot be ignored when studying the influence of radiation on the migratory and invasive capacity of cancer cells. This is especially important in the case of pancreatic malignancies that are characterized by an abundance of stromal cells, including cancer-associated fibroblasts, which are known to orchestrate the cross-talk with tumor cells.

Aim

The current study aims to investigate whether the presence of factors released by irradiated fibroblasts affects the migratory and invasive capacity of pancreatic cancer cells exposed to different doses of photons or C-ions.

Materials and methods

AsPC-1 and AG01522 cells were irradiated with the same dose of photons or C-ions at room temperature. Through Boyden chamber assay, we tested whether factors secreted by irradiated fibroblasts may influence tumor cell migration, while the invasiveness of AsPC-1 cells was assessed using matrigel precoated inserts in which medium collected from non-irradiated (0 Gy), photon and C-ion irradiated fibroblasts, was added. Data were analyzed by Student t-test using GraphPad software. The mean ± s.d. was determined with a significance level of p<0.05.

Results

In the presence of conditioned medium collected from 1 Gy and 2 Gy photon irradiated fibroblasts, the number of migrated tumor cells increased (P<0.0360, P<0.0001) but decreased at 4 Gy dose (P<0.002). There was a trend of reduction in migration (P<0.0460, P<0.038, P<0.0024, P<0.0002), as well as a decrease in invasiveness (P<0.0525, P<0.0035, P<0.0868, P<0.0310) after exposure to 0.5 Gy, 1 Gy, 2 Gy and 4 Gy of C-ions.

Conclusions

The presence of irradiated fibroblasts affected the invasiveness capability of pancreatic cancer cells, probably by the reciprocal release of soluble factors whose production is differently modulated after high or low-LET radiation. Understanding the effects of irradiation on the metastatic potential of pancreatic cancer cells is of utmost importance for improving the outcome and tailoring the therapeutic approach. This challenging scenario requires a continuous and multidisciplinary approach that involves clinicians together with researcher experts in oncological and radiation treatment. In the last years, including preclinical experiences in a multidisciplinary approach has proved to be a winning strategy in clinical oncological research.

Ultrasound-assisted carbon ion dosimetry and range measurement using injectable polymer-shelled phase-change nanodroplets: in vitro study

Methods allowing for in situ dosimetry and range verification are essential in radiotherapy to reduce the safety margins required to account for uncertainties introduced in the entire treatment workflow. This study suggests a non-invasive dosimetry concept for carbon ion radiotherapy based on phase-change ultrasound contrast agents. Injectable nanodroplets made of a metastable perfluorobutane (PFB) liquid core, stabilized with a crosslinked poly(vinylalcohol) shell, are vaporized at physiological temperature when exposed to carbon ion radiation (C-ions), converting them into echogenic microbubbles. Nanodroplets, embedded in tissue-mimicking phantoms, are exposed at 37 °C to a 312 MeV/u clinical C-ions beam at different doses between 0.1 and 4 Gy. The evaluation of the contrast enhancement from ultrasound imaging of the phantoms, pre- and post-irradiation, reveals a significant radiation-triggered nanodroplets vaporization occurring at the C-ions Bragg peak with sub-millimeter shift reproducibility and dose dependency. The specific response of the nanodroplets to C-ions is further confirmed by varying the phantom position, the beam range, and by performing spread-out Bragg peak irradiation. The nanodroplets' response to C-ions is influenced by their concentration and is dose rate independent. These early findings show the ground-breaking potential of polymer-shelled PFB nanodroplets to enable in vivo carbon ion dosimetry and range verification.

Evaluation of the Response of HNSCC Cell Lines to γ-Rays and 12C Ions: Can Radioresistant Tumors Be Identified and Selected for 12C Ion Radiotherapy?

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy worldwide. Thirty percent of patients will experience locoregional recurrence for which median survival is less than 1 year. Factors contributing to treatment failure include inherent resistance to X-rays and chemotherapy, hypoxia, epithelial to mesenchymal transition, and immune suppression. The unique properties of ¹²C radiotherapy including enhanced cell killing, a decreased oxygen enhancement ratio, generation of complex DNA damage, and the potential to overcome immune suppression make its application well suited to the treatment of HNSCC. We examined the ¹²C radioresponse of five HNSCC cell lines, whose surviving fraction at 3.5 Gy ranged from average to resistant when compared with a larger panel of 38 cell lines to determine if ¹²C irradiation can overcome X-ray radioresistance and to identify biomarkers predictive of ¹²C radioresponse. Cells were irradiated with ¹²C using a SOBP with an average LET of 80 keV/μm (CNAO: Pavia, Italy). RBE values varied depending upon endpoint used. A 37 gene signature was able to place cells in their respective radiosensitivity cohort with an accuracy of 86%. Radioresistant cells were characterized by an enrichment of genes associated with radioresistance and survival mechanisms including but not limited to G2/M Checkpoint MTORC1, HIF1α, and PI3K/AKT/MTOR signaling. These data were used in conjunction with an in silico-based modeling approach to evaluate tumor control probability after ¹²C irradiation that compared clinically used treatment schedules with fixed RBE values vs. the RBEs determined for each cell line. Based on the above analysis, we present the framework of a strategy to utilize biological markers to predict which HNSCC patients would benefit the most from ¹²C radiotherapy.

Multimodal evaluation of 19F-BPA internalization in pancreatic cancer cells for boron capture and proton therapy potential applications

PURPOSE

One of the obstacles to the application of Boron Neutron Capture Therapy (BNCT) and Proton Boron Fusion Therapy (PBFT) concerns the measurement of borated carriers' biodistribution. The objective of the present study was to evaluate the in vitro internalization of the ¹⁹F-labelled p-boronophenylalanine (¹⁹F-BPA) in the human cancer pancreatic cell line (PANC-1) for the potential application of BNCT and PBFT in pancreatic cancer. The ¹⁹F-BPA carrier has the advantage that its bio-distribution may be monitored in vivo using ¹⁹F-Nuclear Magnetic Resonance (¹⁹F NMR).

MATERIALS AND METHODS

The ¹⁹F-BPA internalization in PANC-1 cells was evaluated using three independent techniques on cellular samples left in contact with growing medium enriched with 13.6 mM ¹⁹F-BPA corresponding to a ¹¹B concentration of 120 ppm: neutron autoradiography, which quantifies boron; liquid chromatography hyphenated to tandem mass spectrometry and UV-Diode Array Detection (UV-DAD), which quantifies ¹⁹F-BPA molecule; and ¹⁹F NMR spectroscopy, which detects fluorine nuclei.

RESULTS

Our studies suggested that ¹⁹F-BPA is internalized by PANC-1 cells. The three methods provided consistent results of about 50% internalization fraction at 120 ppm of ¹¹B. Small variations (less than 15%) in internalization fraction are mainly dependent on the proliferation state of the cells.

CONCLUSIONS

The ability of ¹⁹F NMR spectroscopy to study ¹⁹F-BPA internalization was validated by well-established independent techniques. The multimodal approach we used suggests ¹⁹F-BPA as a promising BNCT/PBFT carrier for the treatment of pancreatic cancer. Since the quantification is performed at doses useful for BNCT/PBFT, ¹⁹F NMR can be envisaged to monitor ¹⁹F-BPA bio-distribution during the therapy.

In Vivo Evaluation of Multifunctional Gold Nanorods for Boron Neutron Capture and Photothermal Therapies

The incidence and mortality of cancer demand more innovative approaches and combination therapies to increase treatment efficacy and decrease off-target side effects. We describe a boron-rich nanoparticle composite with potential applications in both boron neutron capture therapy (BNCT) and photothermal therapy (PTT). Our strategy is based on gold nanorods (AuNRs) stabilized with polyethylene glycol and functionalized with the water-soluble complex cobalt bis(dicarbollide) ([3,3'-Co(1,2-C₂B₉H₁₁)₂]^-), commonly known as COSAN. Radiolabeling with the positron emitter copper-64 (⁶⁴Cu) enabled in vivo tracking using positron emission tomography imaging. ⁶⁴Cu-labeled multifunctionalized AuNRs proved to be radiochemically stable and capable of being accumulated in the tumor after intravenous administration in a mouse xenograft model of gastrointestinal cancer. The resulting multifunctional AuNRs showed high biocompatibility and the capacity to induce local heating under external stimulation and trigger cell death in heterogeneous cancer spheroids as well as the capacity to decrease cell viability under neutron irradiation in cancer cells. These results position our nanoconjugates as suitable candidates for combined BNCT/PTT therapies.

The Proton-Boron Reaction Increases the Radiobiological Effectiveness of Clinical Low- and High-Energy Proton Beams: Novel Experimental Evidence and Perspectives

Protontherapy is a rapidly expanding radiotherapy modality where accelerated proton beams are used to precisely deliver the dose to the tumor target but is generally considered ineffective against radioresistant tumors. Proton-Boron Capture Therapy (PBCT) is a novel approach aimed at enhancing proton biological effectiveness. PBCT exploits a nuclear fusion reaction between low-energy protons and ¹¹B atoms, i.e. p+¹¹B→ 3α (p-B), which is supposed to produce highly-DNA damaging α-particles exclusively across the tumor-conformed Spread-Out Bragg Peak (SOBP), without harming healthy tissues in the beam entrance channel. To confirm previous work on PBCT, here we report new in-vitro data obtained at the 62-MeV ocular melanoma-dedicated proton beamline of the INFN-Laboratori Nazionali del Sud (LNS), Catania, Italy. For the first time, we also tested PBCT at the 250-MeV proton beamline used for deep-seated cancers at the Centro Nazionale di Adroterapia Oncologica (CNAO), Pavia, Italy. We used Sodium Mercaptododecaborate (BSH) as ¹¹B carrier, DU145 prostate cancer cells to assess cell killing and non-cancer epithelial breast MCF-10A cells for quantifying chromosome aberrations (CAs) by FISH painting and DNA repair pathway protein expression by western blotting. Cells were exposed at various depths along the two clinical SOBPs. Compared to exposure in the absence of boron, proton irradiation in the presence of BSH significantly reduced DU145 clonogenic survival and increased both frequency and complexity of CAs in MCF-10A cells at the mid- and distal SOBP positions, but not at the beam entrance. BSH-mediated enhancement of DNA damage response was also found at mid-SOBP. These results corroborate PBCT as a strategy to render protontherapy amenable towards radiotherapy-resilient tumor. If coupled with emerging proton FLASH radiotherapy modalities, PBCT could thus widen the protontherapy therapeutic index.

A New Platinum-Based Prodrug Candidate for Chemotherapy and Its Synergistic Effect With Hadrontherapy: Novel Strategy to Treat Glioblastoma

Glioblastoma (GBM) is the most common tumor of the central nervous system. Current therapies, often associated with severe side effects, are inefficacious to contrast the GBM relapsing forms. In trying to overcome these drawbacks, (OC-6-44)-acetatodiamminedichlorido(2-(2-propynyl)octanoato)platinum(IV), also called Pt(IV)Ac-POA, has been recently synthesized. This new prodrug bearing as axial ligand (2-propynyl)octanoic acid (POA), a histone deacetylase inhibitor, has a higher activity due to (i) its high cellular accumulation by virtue of its high lipophilicity and (ii) the inhibition of histone deacetylase, which leads to the increased exposure of nuclear DNA, permitting higher platination and promoting cancer cell death. In the present study, we investigated the effects induced by Pt(IV)Ac-POA and its potential antitumor activity in human U251 glioblastoma cell line using a battery of complementary techniques, i.e., flow cytometry, immunocytochemistry, TEM, and Western blotting analyses. In addition, the synergistic effect of Pt(IV)Ac-POA associated with the innovative oncological hadrontherapy with carbon ions was investigated, with the aim to identify the most efficient anticancer treatment combination. Our in vitro data demonstrated that Pt(IV)Ac-POA is able to induce cell death, through different pathways, at concentrations lower than those tested for other platinum analogs. In particular, an enduring Pt(IV)Ac-POA antitumor effect, persisting in long-term treatment, was demonstrated. Interestingly, this effect was further amplified by the combined exposure to carbon ion radiation. In conclusion, Pt(IV)Ac-POA represents a promising prodrug to be incorporated into the treatment regimen for GBM. Moreover, the synergistic efficacy of the combined protocol using chemotherapeutic Pt(IV)Ac-POA followed by carbon ion radiation may represent a promising approach, which may overcome some typical limitations of conventional therapeutic protocols for GBM treatment.

Re-irradiation With Carbon Ion Radiotherapy for Pelvic Rectal Cancer Recurrences in Patients Previously Irradiated to the Pelvis

BACKGROUND/AIM

Re-irradiation of locally recurrent rectal cancer poses challenges due to the proximity of critical organs, such as the bowel. This study aimed at evaluating the safety and efficacy of re-irradiation with Carbon Ion Radiotherapy (CIRT) in rectal cancer patients with local recurrence.

PATIENTS AND METHODS

Between 2014 and 2018, 14 patients were treated at the National Center of Oncological Hadrontherapy (CNAO Foundation) with CIRT for locally recurrent rectal cancer.

RESULTS

All patients concluded the treatment. No G≥3 acute/late reaction nor pelvic infections were observed. The 1-year and 2-year local control rates were, 78% and 52%, respectively, and relapse occurred close to the bowel in 6 patients. The 1-year and 2-year overall survival rates were 100% and 76.2% each; while the 1-year and 2-year metastasis free survival rates were 64.3% and 43%.

CONCLUSION

CIRT as re-irradiation for locally recurrent rectal cancer emerges as a safe and valid treatment with an acceptable rate of morbidity of surrounding healthy tissue.

Effects of Photons Irradiation on 18F-FET and 18F-DOPA Uptake by T98G Glioblastoma Cells

The differential diagnosis between brain tumors recurrence and early neuroinflammation or late radionecrosis is still an unsolved problem. The new emerging magnetic resonance imaging, computed tomography, and positron emission tomography diagnostic modalities still lack sufficient accuracy. In the last years, a great effort has been made to develop radiotracers able to detect specific altered metabolic pathways or tumor receptor markers. Our research project aims to evaluate irradiation effects on radiopharmaceutical uptake and compare the kinetic of the fluorinate tracers. T98G glioblastoma cells were irradiated at doses of 2, 10, and 20 Gy with photons, and ¹⁸F-DOPA and ¹⁸F-FET tracer uptake was evaluated. Activity and cell viability at different incubation times were measured. ¹⁸F-FET and ¹⁸F-DOPA are accumulated via the LAT-1 transporter, but ¹⁸F-DOPA is further incorporated, whereas ¹⁸F-FET is not metabolized. Therefore, time-activity curves (TACs) tend to plateau with ¹⁸F-DOPA and to a rapid washout with ¹⁸F-FET. After irradiation, ¹⁸F-DOPA TAC resembles the ¹⁸F-FET pattern. ¹⁸F-DOPA activity peak we observed at 20 min might be fictitious, because earlier time points have not been evaluated, and a higher activity peak before 20 min cannot be excluded. In addition, the activity retained in the irradiated cells remains higher in comparison to the sham ones at all time points investigated. This aspect is similar in the ¹⁸F-FET TAC but less evident. Therefore, we can hypothesize the presence of a second intracellular compartment in addition to the amino acidic pool one governed by LAT-1, which could explain the progressive accumulation of ¹⁸F-DOPA in unirradiated cells.

[The risk of second radiation-induced cancer from hadrontherapy compared to traditional radiotherapy]

Radiation therapy increasingly plays a fundamental role in the treatment of cancer. Since the survival of cancer patients is continuously improving, the late effects of treatments, including those related to radiation treatment, can affect the quality of life and health and of the patients themselves to a greater extent. Especially in the last 20 years, with the implementation of new techniques/forms of radiation therapy, the risk of developing radiation-induced tumors following radiation therapy has become a hotly debated topic. Malignant tumors induced by radiation therapy represent a particularly important problem for pediatric patients, who are intrinsically more sensitive to carcinogens than adults and have a longer life expectancy. To date, there is only one study in the literature, from 2019, which analyzes the risk of secondary tumors after carbon ion radiation compared to surgery or photon treatment and refers to patients treated for prostate cancer. Despite the high degree of uncertainty, the data acquired so far suggest that particle radiation therapy, especially with protons delivered with active scanning, carries a lower risk of radiation-induced tumors than conventional photon therapies. This is largely due to the lower doses to which healthy tissues are exposed and the low relative risk associated with exposure to neutrons throughout the body, especially when active scanning beams are used.

Hadron Therapy, Magnetic Nanoparticles and Hyperthermia: A Promising Combined Tool for Pancreatic Cancer Treatment

A combination of carbon ions/photons irradiation and hyperthermia as a novel therapeutic approach for the in-vitro treatment of pancreatic cancer BxPC3 cells is presented. The radiation doses used are 0–2 Gy for carbon ions and 0–7 Gy for 6 MV photons. Hyperthermia is realized via a standard heating bath, assisted by magnetic fluid hyperthermia (MFH) that utilizes magnetic nanoparticles (MNPs) exposed to an alternating magnetic field of amplitude 19.5 mTesla and frequency 109.8 kHz. Starting from 37 °C, the temperature is gradually increased and the sample is kept at 42 °C for 30 min. For MFH, MNPs with a mean diameter of 19 nm and specific absorption rate of 110 ± 30 W/g_Fe3o₄ coated with a biocompatible ligand to ensure stability in physiological media are used. Irradiation diminishes the clonogenic survival at an extent that depends on the radiation type, and its decrease is amplified both by the MNPs cellular uptake and the hyperthermia protocol. Significant increases in DNA double-strand breaks at 6 h are observed in samples exposed to MNP uptake, treated with 0.75 Gy carbon-ion irradiation and hyperthermia. The proposed experimental protocol, based on the combination of hadron irradiation and hyperthermia, represents a first step towards an innovative clinical option for pancreatic cancer.

Outcome and Toxicity of Carbon Ion Radiotherapy for Axial Bone and Soft Tissue Sarcomas

BACKGROUND/AIM

Definitive radiotherapy for bone and soft tissues sarcomas benefits patients deemed unfit for surgery; poor outcomes have been reported with conventional photons, while interesting preliminary results have been described with particle in single-Institution experiences. The aim of the study was to retrospectively evaluate preliminary results of carbon ion radiotherapy (CIRT) in patients with axial bone and soft tissue sarcomas (BSTS) treated with curative intent at the National Center for Oncological Hadrontherapy (CNAO).

PATIENTS AND METHODS

From January 2013 to September 2018, 54 patients with axial BSTS were treated with CIRT at CNAO. Their median age was 50 years (range=19-79 years), males/females=1.4:1. Tumor site was the pelvis in 50% of cases (n=27), thoracic region in 24% (n=13), cervical spine in 15% (n=8) and lumbar in 11% (n=6). A total of 76% (n=41) of patients had primary disease, while 24% (n=13) had recurrent disease. Before CIRT, surgery was performed in 47% of cases, including positive margins (R1) in 8 patients, and macroscopic residual disease (R2) in 17. Histological subtypes were mainly represented by chondrosarcomas in 39% (n=21) of patients and osteosarcomas in 24% (n=13). Pre-treatment chemotherapy was administered in 40% of cases (n=22); no patient received previous radiotherapy. All treatments were performed with active scanning CIRT for a median total dose of 73.6 Gy (range=70.4-76.8 Gy), in 16 fractions (4 fractions per week).

RESULTS

Median follow-up was 24 months (range=4-61 months). Four patients were lost to follow-up. Acute toxicities were mild, no >G2 event was reported and no treatment interruption was required. For late toxicity, only G3 neuropathy was detected in 4% of cases (n=2). With a median time to local progression of 13 months (3-35), 15 local failures were observed, resulting in 2- and 3-year local control rates of 67.4% for both. Distant progression occurred in 12 patients, with 1-year progression-free survival (PFS) rate of 97.5%; 2- and 3-year rates were 92.2%. Fifteen patients died resulting in 1- 2- and 3-years overall survival (OS) rates of 87.1%, 75.4% and 64%, respectively. At log-rank test, gross total volume (GTV) >1,000 ml was found to be predictive of local failure (p=0.04), pre-treatment chemotherapy was found to be significantly related to PFS and OS (p=0.02 and p=0.016); also, recurrent disease and distant progression were significantly related to OS (p=0.019 and p=0.0013). Cox proportional-hazards model confirmed that GTV >1,000 ml was related to worse local control (p=0.0010).

CONCLUSION

CIRT for axial BSTS resulted in mild toxicity, showing promising results in terms of clinical outcomes. A longer follow-up is warranted.

Is Proton Beam Radiotherapy Worthwhile in the Management of Angiosarcoma of the Scalp?

In inoperable patients, the management of angiosarcoma of the scalp is challenging. Due to intrinsic, dosimetric and radiobiological properties, proton beam radiotherapy may be an effective and safe option to offer to these difficult-to-cure patients. Here, we report a case of angiosarcoma of the scalp treated successfully with proton beam radiotherapy. Angiosarcoma is a rare malignancy concerning around 2% of soft-tissue sarcomas and 5% of cutaneous soft-tissue sarcomas. Cutaneous angiosarcomas can occur in any part of the body, but the head and neck region is a common primary site and the scalp is a frequent site in elderly patients.

The Role of Particle Therapy in the Risk of Radio-induced Second Tumors: A Review of the Literature

One of the most important late side-effects of radiation therapy is the development of radiation-induced secondary malignancies. In the last years, this topic has significantly influenced treatment decision-making as the number of long-term cancer survivors has significantly increased with advances in treatment modalities. All efforts are being made to prevent the incidence of tumors induced by radiation. In this review article we summarize the current knowledge about treatment-related secondary cancers with a particular attention to hadrontherapy.

Preoperative chemotherapy and carbon ions therapy for treatment of resectable and borderline resectable pancreatic adenocarcinoma: a prospective, phase II, multicentre, single-arm study

Background

Pancreatic adenocarcinoma is a high-mortality neoplasm with a documented 5-years-overall survival around 5%. In the last decades, a real breakthrough in the treatment of the disease has not been achieved. Here we propose a prospective, phase II, multicentre, single-arm study aiming to assess the efficacy and the feasibility of a therapeutic protocol combining chemotherapy, carbon ion therapy and surgery for resectable and borderline resectable pancreatic adenocarcinoma.

Method

The purpose of this trial (PIOPPO Protocol) is to assess the efficacy and the feasibility of 3 cycles of FOLFIRINOX neoadjuvant chemotherapy followed by a short-course of carbon ion radiotherapy (CIRT) for resectable or borderline resectable pancreatic adenocarcinoma patients. Primary outcome of this study is the assessment of local progression free survival (L-PFS). The calculation of sample size is based on the analysis of the primary endpoint “progression free survival” according to Fleming’s Procedure.

Discussion

Very preliminary results provide initial evidence of the feasibility of the combined chemotherapy and CIRT in the neoadjuvant setting for resectable or borderline resectable pancreatic cancer. Completion of the accrual and long term results are awaited to see if this combination of treatment is advisable and will provide the expected benefits.

Trial registration

ClinicalTrials.gov Identifier: NCT03822936 registered on January 2019.

Carbon Ion Radiotherapy in the Management of Unusual Liposarcomas: A Case Report

BACKGROUND

Liposarcomas are the most common soft-tissue sarcomas in adulthood. Orbital and spermatic cord liposarcomas are uncommon and there is no consensus on their management. The treatment of choice is wide excision, which may be destructive and lead to unacceptable morbidity. When surgery is declined by patients and in recurrent disease, management can be challenging. We report two cases of liposarcoma treated with carbon ion radiotherapy at the National Center for Oncological Hadrontherapy (Fondazione CNAO) in Italy.

CASE REPORT

A woman with orbital liposarcoma and a man with spermatic cord liposarcoma were referred to our Center and accepted for carbon ion radiotherapy. The treatment was well tolerated and late toxicities were mild. Good local control was achieved in patients.

CONCLUSION

In our experience, carbon ion radiotherapy is an effective and safe option, especially in cases of tumor at high risk for local relapse, in patients with multiple local recurrences, and in patients who refuse destructive surgery.

Feasibility of Carbon Ion Radiotherapy in the Treatment of Gynecological Melanoma

BACKGROUND

Malignant melanoma of the lower genital tract is a rare disease known to have a poor prognosis. Because of the high rate of distant metastasis and unsatisfactory survival benefit, a more conservative treatment approach, instead of extensive surgery, may be warranted. Gynecological melanoma is a radioresistant tumor, an ideal disease to test the biological efficacy of carbon ion radiotherapy (CIRT).

AIM

To report our preliminary experience with CIRT in the treatment of gynecological melanoma at the National Center of Oncological Hadrontherapy (CNAO).

PATIENTS AND METHODS

Between January 2016 and February 2017, four patients were admitted for CIRT at CNAO. A case of cervical melanoma was treated with palliative aim because of large volume macroscopic disease, while three cases of vaginal melanoma were irradiated with a total dose of 68.8 Gy (relative biological effectiveness) in 16 fractions delivered over 4 weeks (4 days a week).

RESULTS

The age of women ranged between 49 and 72 (median=60.5 years) years. Treatment was well tolerated in all patients and all women completed the scheduled treatment course. During CIRT, toxicity was mild. For patients with vaginal disease, local control was 10.23 and 12.6 months, while that for cervical malignant melanoma was 7.3 months. All patients experienced systemic progression, with median distant metastasis-free survival of 11.7 months. The median overall survival for the whole patient group was 11.41 months.

CONCLUSION

In our first experiences, CIRT appears to be a safe non-invasive option for malignant melanoma of the lower genital tract, but more data and longer follow-up are necessary in order to evaluate the effectiveness and late effects.

Carbon Ion Radiotherapy in the Management of the Tumors of the Peripheral Nervous System

BACKGROUND/AIM

Malignant peripheral nerve sheaths tumors (MPNST) are rare, highly aggressive and radioresistant tumors of soft tissue. Carbon ion radiotherapy (CIRT) seems to be an attractive treatment option when surgery is not possible or refused by the patient. The aim of this study was to report our preliminary results (outcomes and toxicity) of CIRT in the treatment of MPNSTs.

PATIENTS AND METHODS

Our study retrospectively analyzed 13 patients (median age=54 years; range=23-72 years) with MPNST treated with CIRT for a median total dose of 73.6 Gy (relative biological effectiveness) (range=70.4-76.8 Gy) between 2013 and 2016.

RESULTS

Six local progressions were recorded, with a median local progression-free survival of 23.2 months (range=2.2-45.4 months). Acute toxicities were mild. Late toxicity of grade 2 or more was noted in two patients.

CONCLUSION

CIRT yielded good local control with a low rate of acute and late toxicities.

Effects of L-DOPA Pretreatment on the Kinetics, Migration and Carbon Ion Radiation Response of T98G Cells

BACKGROUND/AIM

Glioblastoma is the most malignant and widespread brain tumor in adults, with a rapid clinical course. Recently, it has been hypothesized that L-DOPA plays a role in the diagnosis and treatment of glioblastoma. The aim of this study was to assess the effects of pretreatment with L-DOPA on the biological behavior of human T98G cells in vitro.

MATERIALS AND METHODS

T98G cells were treated with 50 μg/ml or 100 μg/ml of L-DOPA for 4 h and their morphology, growth rate, clonogenic survival and migratory capacity in basal conditions and after carbon ion irradiation were evaluated using standard methods.

RESULTS

Treated cells showed a lower growth rate and an increased migratory capacity that correlated with the dose of tested L-DOPA. Treatment with L-DOPA increased the growth rate of carbon ion irradiated T98G cells compared to control non-treated cells exposed to the same radiation dose.

CONCLUSION

Our results open further questions about the overall advantage of L-DOPA treatment of glioblastoma.

Morphological Analysis of Amoeboid-Mesenchymal Transition Plasticity After Low and High LET Radiation on Migrating and Invading Pancreatic Cancer Cells

BACKGROUND/AIM

Cell migration and invasion are fundamental components of tumor cell metastasis that represent the biggest threat to the survival and quality of life of cancer patients. There is clear evidence that ionizing radiation can differently modulate migration and invasiveness of cancer cells depending on the cell lines, the doses and the radiation types investigated. This suggests that motile cells are able to adopt different migration strategies according to their molecular characteristics and external signals.

MATERIALS AND METHODS

In this study, a morphological analysis was performed on pancreatic cancer Aspc-1 cells to evaluate the amoeboid-mesenchymal mobility transition in several experimental conditions considering the role played by factors released by normal and tumor cells, in basal conditions and after low and high Linear Energy Transfer (LET) irradiation.

RESULTS AND CONCLUSION

The migratory behavior of Aspc-1 cells is modulated by factors released by normal fibroblasts and tumor cells, and this is in turn modulated by both the radiation dose and the radiation quality.

Sluggish dorsally-driven inhibition of return during orthographic processing in adults with dyslexia

Dyslexia (D) is a neurodevelopmental reading disorder characterized by phonological and orthographic deficits. Before phonological decoding, reading requires a specialized orthographic system for parallel letter processing that assigns letter identities to different spatial locations. The magnocellular-dorsal (MD) stream rapidly process the spatial location of visual stimuli controlling visuo-spatial attention. To investigate the visuo-spatial attention efficiency during orthographic processing, inhibition of return (IOR) was measured in adults with and without D in a lexical decision task. IOR is the delay in responding to stimuli displayed in a cued location after a long cue-target interval. Only adults with D did not showed IOR effect during letter-string recognition, despite the typical left-hemisphere specialization for word identification. A specific deficit in coherent-dot-motion perception confirmed an MD-stream disorder in adults with D. Our results suggest that adults with D might develop an efficient visual word form area, but a dorsal-attentional dysfunction impairs their reading fluency.

The G-quadruplex-stabilizing ligand RHPS4 enhances sensitivity of U251MG glioblastoma cells to clinical carbon ion beams

The pentacyclic acridine RHPS4 is a highly potent and specific G-quadruplex (G4) ligand, which binds and stabilizes telomeric G4 leading to the block of the replication forks at telomeres and consequently to telomere dysfunctionalization. In turn, the cell recognizes unprotected telomeres as DNA double-strand breaks with consequent activation of DNA repair response at telomeres, cellular growth impairment, and death. Data from the literature showed the capability of this compound to sensitize U251MG glioblastoma radioresistant cell line to X-rays sparsely ionizing radiations. In the present paper, it was investigated whether RHPS4 is also able to increase the effect of clinical carbon ion beams (cells irradiated in the middle of a spread-out Bragg peak, in the energy range of 246-312 MeV·μm^-1 and a dose-averaged linear energy transfer of 46 keV·μm^-1 ). Interestingly, also for charged particles whose damage inflicted to DNA is more complex than that of sparsely ionizing radiations and results in higher Relative Biological Effectiveness (RBE), RHPS4 significantly potentiated the radiation effect in terms of cell killing, delayed rejoining of DNA double-strand breaks (γ-H2AX and 53BBP1 immunofluorescence staining), chromosome aberrations (pan-centromeric/telomeric FISH and multicolor FISH), and G₂ /M-phase accumulation in GBM cells. Overall, the results provide the first evidence that the combined administration of the G4-ligand RHPS4 with charged particles interfere with cellular processes involved in cell survival leading to radiosensitization of highly radioresistant tumor cells.

Evidence of 68Ga-DOTA-NT-20.3 Uptake in Pancreatic Adenocarcinoma AsPC-1 Cell Line - in vitro Study

BACKGROUND

Neurotensin receptors are overexpressed in several cancer types including pancreatic ductal adenocarcinoma. Three NTR subtypes have been cloned: NTR-1, NTR-2 and NTR-3. The most expressed NTR-1 is not present in normal pancreatic tissue and has a low expression in chronic pancreatitis.

OBJECTIVE

Objective of this study was to test in vitro affinity of the new 68Ga labelled neurotensin analogue DOTA-NT-20.3 (fragment 6-13, Ac-Lys(DOTA)-Pro-Arg(N-CH3)-Arg-Pro-Tyr-Tle-Leu) on the human pancreatic ductal adenocarcinoma cell line AsPC-1.

METHOD

For the preparation of 68Ga-DOTA-NT-20.3, 68GaCl3 solution (eluted from 68Ge/68Ga generator) and 50 μg of precursor (Iason, Graz, Austria) water dissolved were used in an automatic synthesis module. The labeled compound was added to cell culture flask and incubated at 37°C. At various time points after tracer addition up to 80min, cells were recovered, rinsed and counted for radioactivity. Results were expressed as percent binding normalized to 200000 cells and affinity parameters were calculated.

RESULTS

Labeling yield was ≥98 %. The molar ratio between labelled and total peptide was about 1/400. AsPC-1 cell line showed rapid uptake of the tracer including surface and internalized binding, tending to a plateau phase 80 min after tracer addition (11%/200.000 cells). The Kd (7.335 pmol) and Bmax (90.52 kBq) value indicated high tracer affinity for AsPC-1cell line especially if compared with the literature data regarding other malignancies (e.g. colonic cancer cell line). Binding sites were 1.09x106 sites per cell.

CONCLUSION

New tracer 68Ga-DOTA-NT-20.3 can be a suitable candidate for the clinical use in patients with pancreatic ductal adenocarcinoma.

Visual motion and rapid auditory processing are solid endophenotypes of developmental dyslexia

Although a genetic component is known to have an important role in the etiology of developmental dyslexia (DD), we are far from understanding the molecular etiopathogenetic pathways. Reduced measures of neurobiological functioning related to reading (dis)ability, i.e. endophenotypes (EPs), are promising targets for gene finding and the elucidation of the underlying mechanisms. In a sample of 100 nuclear families with DD (229 offspring) and 83 unrelated typical readers, we tested whether a set of well-established, cognitive phenotypes related to DD [i.e. rapid auditory processing (RAP), rapid automatized naming (RAN), multisensory nonspatial attention and visual motion processing] fulfilled the criteria of the EP construct. Visual motion and RAP satisfied all testable criteria (i.e. they are heritable, associate with the disorder, co-segregate with the disorder within a family and represent reproducible measures) and are therefore solid EPs of DD. Multisensory nonspatial attention satisfied three of four criteria (i.e. it associates with the disorder, co-segregates with the disorder within a family and represents a reproducible measure) and is therefore a potential EP for DD. Rapid automatized naming is heritable but does not meet other criteria of the EP construct. We provide the first evidence of a methodologically and statistically sound approach for identifying EPs for DD to be exploited as a solid alternative basis to clinical phenotypes in neuroscience.

How to Study Boron Biodistribution in Liver Metastases from Colorectal Cancer

The purpose of this study was to evaluate boron distribution for a safe and effective BNCT (Boron Neutron Capture Therapy) of liver metastases. Samples both from healthy and tumour liver parenchyma were analysed, after i.v. boron administration, by: alpha particles counting under neutron irradiation; morphological analysis by standard haematoxylin-eosin staining; neutron autoradiography. Our method was unaffected by the cytological heterogeneity inside tumour nodules; it demonstrated selective boron distribution in tumour tissue and predicted estimated mean therapeutic doses in tumour and safety doses in healthy tissue. The time interval for efficient BNCT was 2 to 4 hours after i.v. boron administration.

Early effects comparison of X-rays delivered at high-dose-rate pulses by a plasma focus device and at low dose rate on human tumour cells

A comparative study has been performed on the effects of high-dose-rate (DR) X-ray beams produced by a plasma focus device (PFMA-3), to exploit its potential medical applications (e.g. radiotherapy), and low-DR X-ray beams produced by a conventional source (XRT). Experiments have been performed at 0.5 and 2 Gy doses on a human glioblastoma cell line (T98G). Cell proliferation rate and potassium outward currents (IK) have been investigated by time lapse imaging and patch clamp recordings. The results showed that PFMA-3 irradiation has a greater capability to reduce the proliferation rate activity with respect to XRT, while it does not affect IK of T98G cells at any of the dose levels tested. XRT irradiation significantly reduces the mean IK amplitude of T98G cells only at 0.5 Gy. This work confirms that the DR, and therefore the source of radiation, is crucial for the planning and optimisation of radiotherapy applications.

In vivo radiobiological assessment of the new clinical carbon ion beams at CNAO

In this article, the in vivo study performed to evaluate the uniformity of biological doses within an hypothetical target volume and calculate the values of relative biological effectiveness (RBE) at different depths in the spread-out Bragg peak (SOBP) of the new CNAO (National Centre for Oncological Hadrontherapy) carbon beams is presented, in the framework of a typical radiobiological beam calibration procedure. The RBE values (relative to (60)Co γ rays) of the CNAO active scanning carbon ion beams were determined using jejunal crypt regeneration in mice as biological system at the entrance, centre and distal end of a 6-cm SOBP. The RBE values calculated from the iso-effective doses to reduce crypt survival per circumference to 10, ranged from 1.52 at the middle of the SOBP to 1.75 at the distal position and are in agreement with those previously reported from other carbon ion facilities. In conclusion, this first set of in vivo experiments shows that the CNAO carbon beam is radiobiologically comparable with the NIRS (National Institute of Radiological Sciences, Chiba, Japan) and GSI (Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany) ones.