Proton-beam Therapy for Locally Advanced Hepatocellular Carcinoma With Inferior Vena Cava Tumor Thrombus: Case Report.

BACKGROUND/AIM: We report on a case of locally advanced hepatocellular carcinoma (HCC) accompanied by an inferior vena cava tumor thrombus (IVCTT), treated successfully with proton-beam therapy (PBT). CASE REPORT: A 63-year-old male presented with a primary, single HCC with IVCTT, without metastasis to the intrahepatic region, lymph nodes, or distant organs. The clinical staging was identified as T4N0M0 Stage IIIB. The patient's liver function was classified as Child-Pugh class A (score: 6), with a modified albumin-bilirubin (mALBI) grade of 2a. The patient had liver cirrhosis due to non-alcoholic steatohepatitis. Magnetic resonance imaging revealed a nodular tumor measuring 13.2×8.9×9.8 cm across segments 1, 6, 7, and 8, along with IVCTT. The patient received PBT, with a total dose of 72.6 Gy (relative biological effectiveness) delivered in 22 fractions. Throughout the PBT treatment, the patient experienced no acute toxicities and completed the therapy as planned. Twelve months following PBT, the patient was alive without evidence of local recurrence, lymph node involvement, or distant organ metastasis. The only late toxicity observed was a mild worsening of the mALBI grade. CONCLUSION: We observed a favorable local response with manageable toxicities in a patient with locally advanced HCC and IVCTT treated with PBT. While this is a single case report, our findings suggest that PBT could be considered a viable treatment option for HCC with IVCTT.

Dosimetric investigation of whole-brain radiotherapy with helical intensity modulated radiation therapy and volumetric modulated arc therapy for scalp sparing.

Objective: Intensity-modulated radiotherapy (IMRT) is a well-established radiotherapy technique for delivering radiation to cancer with high conformity while sparing the surrounding normal tissue. Two main purposes of this study are: (1) to investigate dose calculation accuracy of helical IMRT (HIMRT) and volumetric-modulated arc therapy (VMAT) on surface region and (2) to evaluate the dosimetric efficacy of HIMRT and VMAT for scalp-sparing in whole brain radiotherapy (WBRT). Methods: First, using a radiochromic film and water-equivalent phantom with three types of boluses (1, 3, 5 mm), calculation/measurement dose agreement at the surface region in the VMAT and HIMRT plans were examined. Then, HIMRT, 6MV-VMAT and 10MV-VMAT with scalp-sparing, and two conventional three-dimensional conformal radiotherapy plans (6MV-3DCRT and 10MV-3DCRT; as reference data) were created for 30 patients with brain metastasis (30 Gy/10 fractions). The mean dose to the scalp and the scalp volume receiving 24 and 30 Gy were compared. Results: The percentage dose differences between the calculation and measurement were within 7%, except for the HIMRT plan at a depth of 1 mm. The averaged mean scalp doses [Gy], V24Gy [%], and V30Gy [%] (1SD) for 6MV-3DCRT, 10MV-3DCRT, HIMRT, 6MV-VMAT, and 10MV-VMAT were [26.6 (1.1), 86.4 (7.3), 13.2 (4.2)], [25.4 (1.0), 77.8 (7.5), 13.2 (4.2)], [23.2 (1.5), 42.8 (19.2), 0.2 (0.5)], [23.6 (1.6), 47.5 (17.9), 1.2 (1.8)], and [22.7 (1.7), 36.4 (17.6), 0.7 (1.1)], respectively. Conclusion: Regarding the dose parameters, HIMRT achieved a lower scalp dose compared with 6MV-VMAT. However, the highest ability to reduce the mean scalp dose was showed in 10MV-VMAT. Advances in knowledge: Scalp-sparing WBRT using HIMRT or VMAT may prevent radiation-induced alopecia in patients with BM.

Multi-Institutional Study of End-to-End Dose Delivery Quality Assurance Testing for Image-Guided Brachytherapy Using a Gel Dosimeter.

PURPOSE: To quantify dose delivery errors for high-dose-rate image-guided brachytherapy (HDR-IGBT) using an independent end-to-end dose delivery quality assurance test at multiple institutions. The novelty of our study is that this is the first multi-institutional end-to-end dose delivery study in the world. MATERIALS AND METHODS: The postal audit used a polymer gel dosimeter in a cylindrical acrylic container for the afterloading system. Image acquisition using computed tomography, treatment planning, and irradiation were performed at each institution. Dose distribution comparison between the plan and gel measurement was performed. The percentage of pixels satisfying the absolute-dose gamma criterion was reviewed. RESULTS: Thirty-five institutions participated in this study. The dose uncertainty was 3.6% ± 2.3% (mean ± 1.96σ). The geometric uncertainty with a coverage factor of k = 2 was 3.5 mm. The tolerance level was set to the gamma passing rate of 95% with the agreement criterion of 5% (global)/3 mm, which was determined from the uncertainty estimation. The percentage of pixels satisfying the gamma criterion was 90.4% ± 32.2% (mean ± 1.96σ). Sixty-six percent (23/35) of the institutions passed the verification. Of the institutions that failed the verification, 75% (9/12) had incorrect inputs of the offset between the catheter tip and indexer length in treatment planning and 17% (2/12) had incorrect catheter reconstruction in treatment planning. CONCLUSIONS: The methodology should be useful for comprehensively checking the accuracy of HDR-IGBT dose delivery and credentialing clinical studies. The results of our study highlight the high risk of large source positional errors while delivering dose for HDR-IGBT in clinical practices.

Treatment Outcome of the Combination Therapy of High-dose rate Intracavitary Brachytherapy and Intensity-modulated Radiation Therapy With Central-shielding for Cervical Cancer.

BACKGROUND/AIM: This study aimed to evaluate the clinical outcome of intensity-modulated radiation therapy (IMRT) and high-dose-rate intracavitary brachytherapy (HDR-ICBT) in uterine cervical cancer (UCC). IMRT consisted of whole-pelvic radiation therapy (WPRT) and sequential WPRT with central-shielding (WPRT-CS). PATIENTS AND METHODS: Thirty UCC patients treated with IMRT using TomoTherapy, were retrospectively analyzed. RESULTS: The median dose of WPRT and WPRT-CS was 36 and 14.4 Gy and the median total dose of these was 50 Gy in 25 fractions (Fr). Median HDR-ICBT dose/Fr to Point A was 25 Gy/5 Fr. Median 2 Gy per fraction-equivalent dose (EQD2) of combined WPRT and HDR-ICBT to Point A (α/ß=10) was 71.0 Gy. The 3-year local control, disease-free survival, and overall survival rates were 89.9%, 83.3%, and 86.3%. CONCLUSION: IMRT of WPRT and WPRT-CS given in combination with HDR-ICBT was a feasible therapy resulting in good disease control and tolerance in patients with UCC.

Intensity-modulated Radiation Therapy for Lymph Node Oligo-recurrence.

BACKGROUND/AIM: This study aimed to evaluate the effect of intensity-modulated radiation therapy (IMRT) on the clinical outcomes of patients with lymph node (LN) oligo-recurrence and a controlled primary tumor. PATIENTS AND METHODS: We retrospectively reviewed the medical records of 21 patients diagnosed with LN oligo-recurrence who received IMRT with curative intent. Patients with tumor of various primary sites and histopathological types were included in this study. RESULTS: The 3-year overall survival (OS) and in-field progression-free survival (PFS) rates were 75% and 52%, respectively. Statistical analysis showed that lower dose to the gross tumor volume (GTV) and larger GTV were significantly associated with poorer OS; adenocarcinoma and lower dose to GTV were significantly associated with poorer in-field PFS. No patients experienced severe adverse events. CONCLUSION: IMRT may provide a safe and effective treatment for patients with LN oligo-recurrence. Tumor dose-escalation sparing normal tissue using IMRT technology may improve the OS and in-field PFS.

Multi-institutional comparison of secondary check of treatment planning using computer-based independent dose calculation for non-C-arm linear accelerators.

PURPOSE: This report covers the first multi-institutional study of independent monitor unit (MU)/dose calculation verification for the CyberKnife, Vero4DRT, and TomoTherapy radiotherapy delivery systems. METHODS: A total of 973 clinical treatment plans were collected from 12 institutions. Commercial software employing the Clarkson algorithm was used for verification after a measurement validation study, and the doses from the treatment planning systems (TPSs) and verification programs were compared on the basis of the mean value ±â€¯two standard deviations. The impact of heterogeneous conditions was assessed in two types of sites: non-lung and lung. RESULTS: The dose difference for all locations was 0.5 ±â€¯7.2%. There was a statistically significant difference (P < 0.01) in dose difference between non-lung (-0.3 ±â€¯4.4%) and lung sites (3.5 ±â€¯6.7%). Inter-institutional comparisons showed that various systematic differences were associated with the proportion of different treatment sites and heterogeneity correction. CONCLUSIONS: This multi-institutional comparison should help to determine the departmental action levels for CyberKnife, Vero4DRT, and TomoTherapy, as patient populations and treatment sites may vary between the modalities. An action level of ±5% could be considered for intensity-modulated radiation therapy (IMRT), non-IMRT, and volumetric modulated arc radiotherapy using these modalities in homogenous and heterogeneous conditions with a large treatment field applied to a large region of homogeneous media. There were larger systematic differences in heterogeneous conditions with a small treatment field because of differences in heterogeneity correction with the different dose calculation algorithms of the primary TPS and verification program.