Carbon-ion radiotherapy for locoregional recurrence after primary surgery for pancreatic cancer

Evaluation of the availability of single-position treatment with a rotating gantry and the validity of deformable image registration dose assessment for pancreatic cancer carbon-ion radiotherapy

BACKGROUND

This study aimed to evaluate the clinical acceptability of rotational gantry-based single-position carbon-ion radiotherapy (CIRT) to reduce the gastrointestinal (GI) dose in pancreatic cancer. We also evaluated the usefulness of the deformable image registration (DIR)-based dosimetry method for CIRT.

MATERIAL AND METHODS

Fifteen patients with pancreatic cancer were analyzed. The treatment plans were developed for four beam angles in the supine (SP plan) and prone (PR plan) positions. In the case of using multiple positions, the treatment plan was created with two angles for each of the supine and prone position (SP + PR plan). Dose evaluation for multiple positions was performed in two ways: by directly adding the values of the DVH parameters for each position treatment plan (DVH sum), and by calculating the DVH parameters from the accumulative dose distribution created using DIR (DIR sum). The D2cc and D6cc of the stomach and duodenum were recorded for each treatment plan and dosimetry method and compared.

RESULTS

There were no significant differences among any of the treatment planning and dosimetry methods (p > 0.05). The DVH parameters for the stomach and duodenum were higher in the PR plan and SP plan, respectively, and DVH sum tended to be between the SP and PR plans. DVH sum and DIR sum, DVH sum tended to be higher for D2cc and DIR sum tended to be higher for D6cc.

CONCLUSION

There were no significant differences in the GI dose, which suggests that treatment with a simple workflow performed in one position should be clinically acceptable. In CIRT, DIR-based dosimetry should be carefully considered because of the potential for increased uncertainty due to the steep dose distributions.

Treatment of primary or recurrent non-resectable pancreatic cancer with proton beam irradiation combined with gemcitabine-based chemotherapy

BACKGROUND

Pancreatic cancer accounts for around 4.6% of cancers deaths worldwide per year. Despite many advances in treatment regimes, the prognosis is still poor. Only 20% of tumors are primarily resectable. Recurrences-both with distant metastasis as well as locoregional-are frequent. For patients with primary nonresectable localized disease or localized recurrences, we offered chemoradiation to achieve local control over a long period of time. We here report our results on combined chemoradiation of pancreatic tumors and local recurrences using proton beam therapy.

MATERIALS AND METHODS

We report on 25 patients with localized nonresectable pancreatic cancer (15 patients) or local recurrent disease (10 patients). All patients were treated with combined proton radiochemotherapy. Overall survival, progression-free survival, local control, and treatment-related toxicity were analyzed using statistically methods.

RESULTS

Median RT dose was 54.0 Gy (RBE) for proton irradiation. The toxicity of treatment was acceptable. Four CTCAE grade III and IV adverse events (bone marrow disfunction, gastrointestinal [GI] disorders, stent dislocation, myocardial infarction) were recorded during or directly after the end of radiotherapy; two of them were related to combined chemoradiation (bone marrow disfunction, GI disorders). Six weeks after radiotherapy, one additional grade IV toxicity was reported (ileus, caused by peritoneal carcinomatosis, not treatment related). The median progression-free survival was 5.9 months and median overall survival was 11.0 months. The pretherapy CA19‑9 level was a statistically significant prognostic factor for enhanced overall survival. Local control at 6 months and 12 months were determined to be 86% and 80%, respectively.

CONCLUSION

Combined proton chemoradiation leads to high local control rates. Unfortunately, PFS and OS are driven by distant metastasis and were not improved compared to historical data and reports. With this in mind, enhanced chemotherapeutical regimes, in combination with local irradiation, should be evaluated.

Carbon-Ion Radiotherapy Combined with Concurrent Chemotherapy for Locally Advanced Pancreatic Cancer: A Retrospective Case Series Analysis

Systemic chemotherapy has significantly improved in recent years. In this study. the clinical impact of carbon-ion radiotherapy (CIRT) with concurrent chemotherapy for locally advanced unresectable pancreatic cancer (URPC) was evaluated.

METHODS

Patients with URPC who were treated with CIRT between January 2016 and December 2020 were prospectively registered and analyzed. The major criteria for registration were (1) diagnosed as URPC on imaging; (2) pathologically diagnosed adenocarcinoma; (3) no distant metastasis; (4) Eastern Cooperative Oncology Group performance status of 0-2; (5) tumors without gastrointestinal tract invasion; and (6) available for concurrent chemotherapy. Patients who received neoadjuvant chemotherapy (NAC) for more than one year prior to CIRT were excluded.

RESULTS

Forty-four patients met the inclusion criteria, and thirty-seven received NAC before CIRT. The median follow-up period of living patients was 26.0 (6.0-68.6) months after CIRT. The estimated two-year overall survival, local control, and progression-free survival rates after CIRT were 56.6%, 76.1%, and 29.0%, respectively. The median survival time of all patients was 29.6 months after CIRT and 34.5 months after the initial NAC.

CONCLUSION

CIRT showed survival benefits for URPC even in the multiagent chemotherapy era.

Carbon-Ion Beam Irradiation and the miR-200c Mimic Effectively Eradicate Pancreatic Cancer Stem Cells Under in vitro and in vivo Conditions

Purpose

The study investigated the molecular mechanisms that killed pancreatic cancer cells, including cancer stem cells (CSCs), by carbon ion beam irradiation alone or in combination with miRNA-200c under in vitro and in vivo conditions.

Methods

Human pancreatic cancer (PC) cells, PANC1 and PK45, were treated with carbon-ion beam irradiation alone or in combination with microRNA-200c (miR-200c) mimic. Cell viability assay, colony and spheroid formation assay, quantitative real-time PCR analysis of apoptosis-, autophagy-, and angiogenesis-related gene expression, xenograft tumor control and histopathological analyses were performed.

Results

The cell viability assay showed that transfection of the miRNA-200c (10 nM) mimic into pancreatic CSC (CD44+/ESA+) and non-CSC (CD44-/ESA-) significantly suppressed proliferation of both types of cell populations described above. Combining carbon-ion beam irradiation with the miRNA-200c mimic significantly reduced the colony as well as spheroid formation abilities compared to that observed with the treatment of carbon-ion beam alone or X-ray irradiation combined with the miRNA-200c mimic. Moreover, the combination of carbon ion beam irradiation and miRNA-200c mimic increased the expression of apoptosis-related gene BAX, autophagy-related genes Beclin-1 and p62, addition of gemcitabine (GEM) further enhanced the expression of these genes. In vivo data showed that carbon-ion beam irradiation in combination with the miRNA-200c mimic effectively suppressed xenograft tumor growth and significantly induced tumor necrosis and cavitation.

Conclusion

The combination of miRNA-200c mimic and carbon ion beam irradiation may be powerful radiotherapy that significantly kills pancreatic cancer cells containing CSCs and enhances the effect of carbon-ion beam irradiation compared to carbon-ion beam irradiation alone.

Carbon ion radiotherapy as definitive treatment in locally recurrent pancreatic cancer

Purpose

Data on management of locally recurrent pancreatic cancer (LRPC) after primary resection are limited. Recently, surprisingly high overall survival rates were reported after irradiation with carbon ions. Here, we report on our clinical experience using carbon ion radiotherapy as definitive treatment in LRPC at the Heidelberg Ion-Beam Therapy Center (HIT).

Methods

Between 2015 and 2019, we treated 13 patients with LRPC with carbon ions with a median total dose of 48 Gy (RBE) in 12 fractions using an active raster-scanning technique at a rotating gantry. No concomitant chemotherapy was administered. Overall survival, local control, and toxicity rates were evaluated 18 months after the last patient finished radiotherapy.

Results

With a median follow-up time of 9.5 months, one patient is still alive (8%). Median OS was 12.7 months. Ten patients (77%) developed distant metastases. Additionally, one local recurrence (8%) and two regional tumor recurrences (15%) were observed. The estimated 1‑year local control and locoregional control rates were 87.5% and 75%, respectively. During radiotherapy, we registered one gastrointestinal bleeding CTCAE grade III (8%) due to gastritis. The bleeding was sufficiently managed with conservative therapy. No further higher-grade acute or late toxicities were observed.

Conclusion

We demonstrate high local control rates in a rare cohort of LRPC patients treated with carbon ion radiotherapy. The observed median overall survival rate was not improved compared to historical in-house data using photon radiotherapy. This is likely due to a high rate of distant tumor progression, highlighting the necessity of additional chemotherapy.

Who Will Benefit from Charged-Particle Therapy?

Charged-particle therapy (CPT) such as proton beam therapy (PBT) and carbon-ion radiotherapy (CIRT) exhibit substantial physical and biological advantages compared to conventional photon radiotherapy. As it can reduce the amount of radiation irradiated in the normal organ, CPT has been mainly applied to pediatric cancer and radioresistent tumors in the eloquent area. Although there is a possibility of greater benefits, high set-up cost and dearth of high level of clinical evidence hinder wide applications of CPT. This review aims to present recent clinical results of PBT and CIRT in selected diseases focusing on possible indications of CPT. We also discussed how clinical studies are conducted to increase the number of patients who can benefit from CPT despite its high cost.

Impact of FAPI-PET/CT on Target Volume Definition in Radiation Therapy of Locally Recurrent Pancreatic Cancer

Simple Summary

We demonstrate how manual target definition based on contrast-enhanced computed tomography is highly unreliable and inconsistent. In a second step, we used a novel positron emission tomography tracer, FAPI (68Ga-labeled fibroblast activation protein inhibitor) for target volume definition. FAPI-PET/CT contains biologic information as it visualizes cancer associated fibroblasts. The pioneering use of FAPI PET/CT in radiation treatment planning improved target definition in locally recurrent pancreatic cancer.

Abstract

(1) Background: A new radioactive positron emission tomography (PET) tracer uses inhibitors of fibroblast activation protein (FAPI) to visualize FAP-expressing cancer associated fibroblasts. Significant FAPI-uptake has recently been demonstrated in pancreatic cancer patients. Target volume delineation for radiation therapy still relies on often less precise conventional computed tomography (CT) imaging, especially in locally recurrent pancreatic cancer patients. The need for improvement in precise tumor detection and delineation led us to innovatively use the novel FAPI-PET/CT for radiation treatment planning. (2) Methods: Gross tumor volumes (GTVs) of seven locally recurrent pancreatic cancer cases were contoured by six radiation oncologists. In addition, FAPI-PET/CT was used to automatically delineate tumors. The interobserver variability in target definition was analyzed and FAPI-based automatic GTVs were compared to the manually defined GTVs. (3) Results: Target definition differed significantly between different radiation oncologists with mean dice similarity coefficients (DSCs) between 0.55 and 0.65. There was no significant difference between the volumes of automatic FAPI-GTVs based on the threshold of 2.0 and most of the manually contoured GTVs by radiation oncologists. (4) Conclusion: Due to its high tumor to background contrast, FAPI-PET/CT seems to be a superior imaging modality compared to the current gold standard contrast-enhanced CT in pancreatic cancer. For the first time, we demonstrate how FAPI-PET/CT could facilitate target definition and increases consistency in radiation oncology in pancreatic cancer.

Robustness of daily dose for each beam angle and accumulated dose for inter-fractional anatomical changes in passive carbon-ion radiotherapy for pancreatic cancer: Bone matching versus tumor matching

PURPOSE

We aimed to assess the robustness of accumulated dose distributions for inter-fractional changes in passive carbon-ion radiotherapy for pancreatic cancer.

METHODS

Ninety-five daily CT image sets acquired after the treatment of eight patients with pancreatic cancer were used in this prospective study. Dose distributions with treatment beam fields were recalculated for bone matching (BM) and tumor matching (TM) positions on all daily CT images, the accumulated doses being calculated using deformable image registration methods. The prescribed dose was 55.2 Gy (relative biological effectiveness [RBE]) in 12 fractions. Dose volume parameters of V95 (%) for CTV and GTV, and D2cc (Gy(RBE)) for the stomach and duodenum were evaluated.

RESULTS

The medians (range) of CTV V95 (%) were 91.9 (86.1-100.0), 80.5 (56.1-90.6), and 86.4 (72.5-96.5) for the Plan, accumulated with BM and TM, respectively; GTV values (%) were 98.0 (85.7-100.0), 93.3 (65.7-99.9), and 96.2 (84.8-100.0), respectively. There were significant differences between all combinations apart from the Plan and TM for both targets. The values of stomach D2cc (Gy(RBE)) were 36.0 (16.9-43.4), 36.7 (17.9-45.0), and 35.2 (16.8-43.5), respectively; duodenum values (Gy(RBE)) were 25.2 (21.3-40.3), 30.1 (23.3-48.6), and 28.3 (20.4-50.6), respectively. There was a significant difference between the Plan and BM for duodenum only.

CONCLUSIONS

TM is recommended over BM because it can achieve higher target dose coverage than BM. Nevertheless, it is not enough in some cases. Further technical improvements are necessary to improve the target dose coverage.

Estimating the Number of Patients Eligible for Carbon Ion Radiotherapy in the United States

Purpose

Carbon ion radiotherapy (CIRT) is an emerging radiotherapy modality with potential advantages over conventional photon-based therapy, including exhibiting a Bragg peak and greater relative biological effectiveness, leading to a higher degree of cell kill. Currently, 13 centers are treating with CIRT, although there are no centers in the United States. We aimed to estimate the number of patients eligible for a CIRT center in the United States.

Materials and Methods

Using the National Cancer Database, we analyzed the incidence of cancers frequently treated with CIRT internationally (glioblastoma, hepatocellular carcinoma, cholangiocarcinoma, locally advanced pancreatic cancer, non-small cell lung cancer, localized prostate cancer, soft tissue sarcomas, and specific head and neck cancers) diagnosed in the United States in 2015. The percentage and number of patients likely benefiting from CIRT was estimated with inclusion criteria from clinical trials and retrospective studies, and that ratio was applied to 2019 cancer statistics. An adaption correction rate was applied to estimate the potential number of patients treated with CIRT. Given the high dependency on prostate and lung cancers and the uncertain adoption of CIRT in those diseases, the data were then reanalyzed excluding those diagnoses.

Results

Of the 1 127 455 new cases of cancer diagnosed in the United States in 2015, there were 213 073 patients (18.9%) eligible for treatment with CIRT based on inclusion criteria. When applying this rate and the adaption correction rate to the 2019 incidence data, an estimated 89 946 patients (42.2% of those fitting inclusion criteria) are eligible for CIRT. Excluding prostate and lung cancers, there were an estimated 8922 patients (10% of those eligible for CIRT) eligible for CIRT. The number of patients eligible for CIRT is estimated to increase by 25% to 27.7% by 2025.

Conclusion

Our analysis suggests a need for CIRT in the United States in 2019, with the number of patients possibly eligible to receive CIRT expected to increase during the coming 5 to 10 years.

A clinical study of curative partial breast irradiation for stage I breast cancer using carbon ion radiotherapy

Background and purpose

Our institute initiated carbon ion radiotherapy research for patients with stage I breast cancer in April 2013. The purpose of this article is to evaluate the treatment outcome of cases treated outside clinical trial up to May 2020.

Materials and methods

Eligibility criteria of the patients were having untreated stage I breast cancer and being unsuitable for operation for physical or mental reasons. The irradiated volume was defined as the gross tumor including intraductal components. The dose escalation study was initially conducted four times a week for a total of 52.8 Gy [relative biological efficacy (RBE)]. After confirming that adverse effects were within acceptable range, the total dose was increased to 60.0 Gy (RBE).

Results

Between April 2013 and November 2015, 14 cases were treated. The median follow up period was 61 months. No adverse toxicities were observed except for grade 1 acute skin reaction in 10 cases. The time required from carbonion radiotherapy to tumor disappearance was 3 months in 1 case, 6 months in 3 cases, 12 months in 4 cases, and 24 months in 5 cases. The third case developed local recurrence 6 months after radiotherapy. Twelve patients with luminal subtype received 5-year endocrine therapy. Thirteen of 14 tumors have been maintaining complete response with excellent cosmetic results.

Conclusions

The time from carbon ion radiotherapy to tumor disappearance was longer than expected, but complete tumor disappearance was observed except for one high-grade case. With careful patient selection, carbonion radiotherapy in patients with stage I breast cancer is deemed effective and safe, and further research is recommended.

Efficacy and feasibility of re-irradiation using carbon ions for pancreatic cancer that recurs after carbon-ion radiotherapy

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Carbon-ion re-irradiation for pancreatic cancer; feasibility and efficacy.

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Adjuvant chemotherapy improve local control of re-irradiation using carbon ions.

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Carbon-ion radiotherapy for recurrent pancreatic cancer; reasonable option.

Background and purpose

Patients who receive carbon-ion radiotherapy (C-ion RT) for primary pancreatic cancer may experience locoregional recurrence; however, the treatment options for such patients are limited. We aimed to investigate the feasibility and efficacy of carbon-ion re-irradiation for patients with pancreatic cancer who experienced recurrence after initial C-ion RT.

Materials and methods

Twenty-one patients with recurrent pancreatic cancer who underwent repeat C-ion RT between December 2010 and November 2016 at our institute were retrospectively evaluated. The sites of post-initial C-ion RT failure were in-field central in 16 patients (76.2%) and marginal in 5 (23.8%). The median doses of initial and repeat C-ion RT were both 52.8 Gy (relative biological effectiveness [RBE]). Thirteen patients (61.9%) received concurrent chemotherapy with re-irradiation, while 11 (52.4%) received adjuvant chemotherapy.

Results

The median follow-up period after re-irradiation was 11 months. The 1-year local control, progression-free survival, and overall survival rates were 53.5%, 24.5%, and 48.7%, respectively. Toxicity data was obtained from the patients’ charts. Only 1 patient (4.8%) developed grade 3 acute toxicities and none developed grade ≥3 late toxicities. Univariate analysis indicated that patients who received adjuvant chemotherapy had significantly improved local control rates compared with those who did not; the 1-year local control rates were 80.0% and 0.0%, respectively (P = 0.0469).

Conclusion

Repeating C-ion RT may be a reasonable option with tolerable toxicity for patients with recurrent pancreatic cancers. Adjuvant chemotherapy appears to improve the local control rate. This is the first study to examine re-irradiation using C-ion for recurrent pancreatic cancer after initial C-ion RT.

Carbon ion radiotherapy as definitive treatment in non-metastasized pancreatic cancer: study protocol of the prospective phase II PACK-study

Background

Radiotherapy is known to improve local tumor control in locally advanced pancreatic cancer (LAPC), although there is a lack of convincing data on a potential overall survival benefit of chemoradiotherapy over chemotherapy alone. To improve efficacy of radiotherapy, new approaches need to be evolved. Carbon ion radiotherapy is supposed to be more effective than photon radiotherapy due to a higher relative biological effectiveness (RBE) and due to a steep dose-gradient making dose delivery highly conformal.

Methods

The present Phase II PACK-study investigates carbon ion radiotherapy as definitive treatment in LAPC as well as in locally recurrent pancreatic cancer. A total irradiation dose of 48 Gy (RBE) will be delivered in twelve fractions. Concurrent chemotherapy is accepted, if indicated. The primary endpoint is the overall survival rate after 12 months. Secondary endpoints are progression free survival, safety, quality of life and impact on tumor markers CA 19–9 and CEA. A total of twenty-five patients are planned for recruitment over 2 years.

Discussion

Recently, Japanese researches could show promising results in a Phase I/II-study evaluating chemoradiotherapy of carbon ion radiotherapy and gemcitabine in LAPC. The present prospective PACK-study investigates the efficacy of carbon ion radiotherapy in pancreatic cancer at Heidelberg Ion Beam Therapy Center (HIT) in Germany.

Trial registration

The trial is registered at ClinicalTrials.gov: NCT04194268 (Retrospectively registered on December, 11th 2019).

Carbon Ion Radiotherapy in the Treatment of Pancreatic Cancer: A Review

Pancreatic cancer is the fourth most common cause of cancer-related morality worldwide, and the prognosis remains poor despite aggressive therapy. Carbon ion radiotherapy has favorable radiobiological and physical characteristics in the treatment, including a higher linear energy transfer and higher relative biological effectiveness, which increase the cell kill while potentially reducing toxicities to nearby normal tissues. Although small, early clinical studies have shown promise in both the resectable and unresectable settings to improve local control and overall survival while minimizing toxicities. Currently, there are several trials, including 2 sponsored by institutions in the United States, investigating the role of carbon ion radiotherapy for the treatment of locally advanced pancreatic cancer.

Carbon ion radiotherapy in pancreatic cancer: A review of clinical data

Despite all efforts, pancreatic cancer remains a highly lethal disease. Only surgical resection offers a realistic chance of survival. But at diagnosis the majority of patients suffer from unresectable disease. Whereas guidelines clearly recommend systemic treatments in metastatic disease, data is limited to support a specific treatment option for locally advanced or borderline resectable pancreatic cancer. Therefore, there is an urgent need to improve treatment schemes addressing patients that suffer from unresectable pancreatic cancer. Chemotherapy, photon radiotherapy and combinations of both have shown improved local control rates but there is still a lack of evidence demonstrating an overall survival benefit of photon radiotherapy if no surgical resection is achieved. Impressive results of Japanese Phase I/II-trials investigating carbon ion radiotherapy in pancreatic cancer attracted global attention. Several studies have been initiated to validate and intensify this promising issue. This review gives an overview of the evidence and current use of carbon ion radiotherapy in pancreatic cancer.

Evaluation of Intensity- and Contour-Based Deformable Image Registration Accuracy in Pancreatic Cancer Patients

We aimed to clarify the accuracy of rigid image registration and deformable image registration (DIR) in carbon-ion radiotherapy (CIRT) for pancreatic cancer. Six patients with pancreatic cancer who were treated with passive irradiation CIRT were enrolled. Three registration patterns were evaluated: treatment planning computed tomography images (TPCT) to CT images acquired in the treatment room (IRCT) in the supine position, TPCT to IRCT in the prone position, and TPCT in the supine position to the prone position. After warping the contours of the original CT images to the destination CT images using deformation matrices from the registration, the warped delineated contours on the destination CT images were compared with the original ones using mean displacement to agreement (MDA). Four contours (clinical target volume (CTV), gross tumor volume (GTV), stomach, duodenum) and four registration algorithms (rigid image registration [RIR], intensity-based DIR [iDIR], contour-based DIR [cDIR], and a hybrid iDIR-cDIR ([hDIR]) were evaluated. The means ± standard deviation of the MDAs of all contours for RIR, iDIR, cDIR, and hDIR were 3.40 ± 3.30, 2.2 1± 2.48, 1.46 ± 1.49, and 1.46 ± 1.37 mm, respectively. There were significant differences between RIR and iDIR, and between RIR/iDIR and cDIR/hDIR. For the pancreatic cancer patient images, cDIR and hDIR had better accuracy than RIR and iDIR.