Clinical Outcomes of Carbon-Ion Radiotherapy for Large-Sized (≥4cm) Hepatocellular Carcinoma

PURPOSE/OBJECTIVE(S)

Radical treatment options for bulky unresectable locally advanced hepatocellular carcinoma (HCC) are limited. The purpose of this study is to evaluate the safety and efficacy of carbon-ion radiotherapy (C-ion RT) for bulky (≥4cm) locally advanced HCC.

MATERIALS/METHODS

We performed a retrospective cohort study of patients with bulky (≥4cm) locally advanced HCC treated by C-ion RT between April 2000 and March 2020 in our institution. The eligibility criteria for this study were: (1) the treatment protocols of 45.0-48.0 Gy/2 fractions or 52.8-60.0 Gy/4 fractions, which proven the safety and efficacy in the past clinical trials; (2) Tumors within 3 intrahepatic lesions and with a maximum tumor diameter of 4 cm or greater; (3) N0M0 status; (4) an Eastern Cooperative Oncology Group performance status of 0 to 2; (5) controllable ascites; (6) Child-Pugh grade was A or B. Overall survival (OS), progression-free survival (PFS), and local control rate (LC) were calculated by the Kaplan-Meier method, and Cox regression analysis was used for multivariate analysis. Adverse events were evaluated by CTCAE ver. 5.0. JMP® 12 (SAS Institute Inc., Cary, NC, USA) was used for all analyses. We defined p < 0.05 as statistically significant.

RESULTS

A total of 187 patients met the criteria and were evaluated. The median patient age was 73 years (range, 37-90), and 139 of 187 patients were male. Child-Pugh grade was A in 163 patients and B in 24. Modified albumin-bilirubin (mALBI) grade was 1 in 96 patients, 2a in 50, and 2b in 41. The number of HCV-related HCC cases was in 80, HBV in 32 and non-B and non-C in 75. In 51 patients, identification of vascular invasion to the first-order branch of the portal vein and/or major hepatic vein was confirmed. The median maximum tumor diameter was 5.1 cm (4.0-13.5 cm). In 76 patients, C-ion RT were treated for recurrence. With a median follow-up period of 25.9 months (range, 1.1-215.1), 2-year overall survival, progression-free survival and local control rates were 68.3% (95% confidence interval [CI], 64.7-72.0%), 39.0% (95% CI, 35.2 - 42.8%) and 86.7% (95% CI, 84.7 - 89.7%), respectively. Late adverse events were observed in 3 patients (1.6%) with Grade 3 liver dysfunction and in 3 patients (1.6%) with Grade 3 skin disorders, but there were no cases of Grade 4 or higher. Multivariate analysis of prognostic factors for overall survival revealed that mALBI grade in 2b(HR:3.13, 1.97-4.78, p<0.0001), tumor status in recurrent treatment (HR:1.50, 1.02-2.21, p = 0.039), the number of tumors in 2 or more (HR:2.16, 1.01-2.17, p = 0.045), and maximum tumor diameter in larger than 6 cm (HR:2.34, 1.50-3.61, p = 0.0001) were the predominant prognostic factors, while age, presence of vascular invasion, AFP and DCP were not.

CONCLUSION

The safety and efficacy of C-ion RT for bulky (≥4cm) locally advanced HCC was demonstrated. These results suggested that C-ion RT may be a new treatment option for locally advanced bulky HCC with no curative treatment options.

Long-Term Clinical Outcome of Carbon Ion Radio Therapy for Hepatocellular Carcinoma in the Caudate Lobe

PURPOSE/OBJECTIVE(S)

Surgical resection is the first-line treatment for hepatocellular carcinoma in the caudate lobe (caudate HCC), but it is often difficult due to the tumor's location. In addition, radiofrequency ablation and transcatheter arterial chemoembolization are also difficult for the same reason. This study aimed to evaluate the safety and efficacy of carbon-ion radiation therapy (C-ion RT) for caudate HCC.

MATERIALS/METHODS

We performed a retrospective cohort study of patients with hepatocellular carcinoma treated by C-ion RT between April 2000 and March 2020 in our institution. The eligibility criteria for this study were: (1) located mainly in the caudate lobe (2) the treatment protocols of 45.0-48.0 Gy/2 fractions or 52.8-60.0 Gy/4 fractions, which proved the safety and efficacy in the past clinical trials; (3) N0M0 status; (4) an Eastern Cooperative Oncology Group performance status (PS) of 0 to 2; (5) controllable ascites. The prescribed dose (Gy) used in this study is relative biological effectiveness (RBE) weighted dose. Overall survival (OS), progression-free survival (PFS), and local control rate (LC) were calculated by the Kaplan-Meier method. Adverse events were evaluated by NCI-CTCAE ver. 5.0. SPSS software version 27.0 (IBM Inc.) was used for all analyses. We defined p-value < 0.05 as statistically significant.

RESULTS

A total of 25 patients met the criteria and were evaluated. The median patient age was 73 years (range 58-89), and 21 of 25 patients were male. The number of patients with PS 0 was 22, PS 1 was 1, and PS 2 was 2. The number of HBV-related HCC cases was in 8, HCV-related HCC cases was in 11, and non-B and non-C cases was in 6. The median maximum tumor diameter was 3.0 cm (1.1-4.8 cm). In 6 patients, identification of vascular invasion to the main trunk of the portal vein and/or major hepatic vein was confirmed. The Child-Pugh (CP) grade was A in 21 patients and B in 4. The modified albumin-bilirubin (mALBI) grade 1 is in 17 patients, 2a in 4, 2b in 4. Prescribed doses were 45 Gy / 2 fr in 3 cases, 48 Gy / 2 fr in 12 cases, 52.8 Gy / 4 fr in 7 cases, and 60 Gy / 4 fr in 3 cases. With a median follow-up period of 43.6 months (range 0.3-85.0), 3-year OS, PFS, and LC were 74% (95% confidence interval [CI], 54.8-93.8%), 32% (95% CI, 11.8-51.4%), and 93% (95% CI, 79.4-106%), respectively. All patients had no Grade 2 or higher adverse events during the observation period.

CONCLUSION

The safety and efficacy of C-ion RT for caudate HCC were demonstrated. These results suggested that C-ion RT may be a promising treatment option for patients with caudate HCC.

U-shape rotating anti-cathode compact X-ray generator: 20 times stronger than the commercially available X-ray source

A new type of U-shape anti-cathode X-ray generator in which the inner surface of a cylindrical target is irradiated by an electron beam has been made by modifying a conventional rotating anti-cathode X-ray generator whose brightness in the catalog is 12 kW mm(-2). The target material (Cu), target radius (50 mm) and rotating speed (6,000 r.p.m.) were not changed in this modification. A brightness of 52 kW mm(-2) was obtained by this U-shape-type X-ray generator. This means that the brightness of the new type is 4.3 times greater than that of the old unmodified one. Furthermore, the new-type X-ray generator yielded a brightness of 129 kW mm(-2) by adding a carbon coating on the Cu target. This means an overall increase of brightness of ten times. The original generator has the highest brightness in the generators of the same class (having a radius of 50 mm and rotation speed of 6,000 r.p.m.). Observations showed that Cu Kα counts at vertical incidence of the electron beam onto the surface of the new target, which is initially optically smooth, decrease as the surface is roughened by a severe thermal stress caused by strong electron beam exposure. Further observation reveals, however, that oblique incidence of the electron beam onto the roughened surface drastically increased the X-ray output and amounts to twice as much as that from a smooth surface at vertical incidence. Thus, at the present stage, an overall increase of brightness has been realised at a level 20 times stronger than that of the original commercially offered X-ray generator that we modified.

Highly bright X-ray generator using heat of fusion with a specially designed rotating anticathode

A new type of rotating anticathode X-ray generator has been developed, in which the electron beam irradiates the inner surface of a U-shaped anticathode (Cu). A high-flux electron beam is focused on the inner surface by optimizing the shape of the bending magnet. The power of the electron beam can be increased to the point at which the irradiated part of the inner surface is melted, because a strong centrifugal force fixes the melted part on the inner surface. When the irradiated part is melted, a large amount of energy is stored as the heat of fusion, resulting in emission of X-rays 4.3 times more brilliant than can be attained by a conventional rotating anticathode. Oscillating translation of the irradiated position on the inner surface during use is expected to be very advantageous for extending the target life. A carbon film coating on the inner surface is considered to suppress evaporation of the target metal and will be an important technique in further realization of highly bright X-ray generation.

Generation of an X-ray microbeam for spectromicroscopy at SPring-8 BL39XU

A pair of elliptical mirrors (KB mirror) was designed and fabricated to realize an energy tunable x-ray microbeam for spectromicroscopy at SPring-8 BL39XU. As is commonly recognized, the obtainable beam size with the aspherical total reflection mirrors is strongly affected with the slope error of the mirror. Considering that the extremely high brilliance of the undulator radiation from the SPring-8, the small mirror size and the small mirror-to-focus distance were employed to minimize effects of the slope error. Preliminary evaluation of the KB mirror was carried out using 10 keV monochromatized undulator radiation. Alignment of the mirror was assisted by the beam monitor system composed of a scintillator and a CCD, and the beam size less than 5 microm can be easily achieved even when the source was fully used. The beam size obtained with this experiment was 2 x 4 microm2 with the photon flux of 1 x 10(10) photons/s. Smaller beam size may be expected with the use of intermediate slits. Characterization of trace elements with the spatial resolution will be carried out by using x-ray fluorescence (XRF) analysis and x-ray absorption fine structure (XAFS) measurements with XRF yield method.

Serum immunoreactive activin A levels in normal subjects and patients with various diseases

We developed and validated a RIA for measuring serum activin A. The least detectable value of this assay was 0.1 micrograms/L, and the antibody used cross-reacted slightly with bovine inhibin (3.2%) and porcine activin AB (10.0%) but not with porcine activin B (< 0.5%). Serum activin A was extracted with acetonitrile and trifluoroacetic acid to get rid of the interaction with possible binding proteins in serum. As a result of this extraction procedure, the dose-response curve of serum extract was parallel to the standard curve and a single immunoreactive (ir-) peak was demonstrated on gel chromatographic analysis with constant recovery rates over 80%. Serum ir-activin A level in healthy adults was 1.27 +/- 0.03 micrograms/L (mean +/- SEM, n = 180); being 1.38 +/- 0.05 micrograms/L (n = 90) in male, and 1.16 +/- 0.05 micrograms/L (n = 90) in female subjects, with a tendency to increase with age. Serum ir-activin A level during pregnancy showed a marked increase with the advance of gestation; 1.65 +/- 0.41 micrograms/L (n = 7) in the early, 4.50 +/- 1.13 micrograms/L (n = 21) in the middle, and 16.32 +/- 2.25 micrograms/L (n = 26) in the late trimester, with a rapid decline after delivery. On the other hand, serum ir-activin A level was elevated in patients with hyperthyroidism (1.91 +/- 0.37 micrograms/L, n = 31), liver cirrhosis (2.03 +/- 0.71 micrograms/L, n = 10), chronic renal failure (3.41 +/- 0.34 micrograms/L, n = 41), and advanced solid cancer (2.24 +/- 0.52 micrograms/L, n = 67). These findings indicate that serum ir-activin A level varies with physiological conditions such as aging and pregnancy, and that it may reflect the altered production and metabolism of activin A in certain diseased conditions.

Regulation of immunoreactive activin A secretion from cultured rat anterior pituitary cells

Immunoreactive activin A (ir-activin A) release from cultured rat anterior pituitary cells was examined by measuring ir-activin A in culture medium by a specific radioimmunoassay. Ir-activin A release into the medium increased over 1-18 days, and reached a maximal level at 12-15 days. The basal levels of ir-activin A in the culture media were 0.70 +/- 0.10 (mean +/- SD), 1.30 +/- 0.36 and 1.83 +/- 0.44 ng/10(6) cells, when cultured for 6 days with 0, 2 and 10% fetal calf serum, respectively. LHRH induced an approximate 1.4-fold increase in ir-activin A release in contrast to a 40-60% inhibition with FSH, but LH did not affect the activin A release. In the presence of 12-o-tetradecanoylphorbol acetate (TPA), iractivin A release was enhanced, but no significant effect was induced by forskolin. Activin A was distinctly immunostained in cultured rat anterior pituitary cells. These results suggested that activin A release from the pituitary is modified by FSH and LHRH, and that the activation of protein kinase C may be involved in the action of LHRH.

Immunoradiometric assay for follistatin: serum immunoreactive follistatin levels in normal adults and pregnant women

A sensitive and specific immunoradiometric assay for follistatin was developed using antifollistatin mouse monoclonal and rabbit polyclonal antibodies. The sensitivity of the assay was 0.5 micrograms/L, and cross-reactivities with recombinant human activin A and bovine inhibin were less than 0.1%. The intra- and interassay coefficients of variation were less than 10%, and the recovery rate was about 90% in human serum. The addition of activin A to the same sample resulted in a minimal influence on follistatin recovery, indicating that this assay system can measure the total level of activin-bound and unbound follistatin. Gel filtration analysis of human serum showed that the majority of immunoreactivity was eluted in a larger molecular size position than that of free follistatin, suggesting that the large part of follistatin is bound to other proteins, presumably activins, in serum. Using this assay, immunoreactive follistatin levels in various biological fluids and human sera were examined. The dose-response curves of porcine follicular and amniotic fluids were parallel to the standard curve, and porcine follicular fluid contained extremely high follistatin immunoreactivity (5.6 mg/L). The serum follistatin level in normal human volunteers was 13.3 +/- 4.7 micrograms/L (mean +/- SD; n = 60), with a tendency to increase gradually with age. On the other hand, the serum follistatin level was remarkably elevated in pregnant women (62.7 +/- 35.3 micrograms/L; n = 57), with a positive correlation with weeks of pregnancy. These data indicated that circulating immunoreactive follistatin is detectable in human serum, and the levels vary with physiological conditions such as aging and pregnancy.

Plasma adenosine concentration in appropriate- and small-for-gestational-age fetuses

OBJECTIVE

Our purpose in this study was to investigate the relationship between fetal plasma adenosine concentration and catecholamine concentration, blood gases, and pH in appropriate- and small-for-gestational-age fetuses.

STUDY DESIGN

Cordocentesis was performed in 23 appropriate- and 14 small-for-gestational-age fetuses at 30 to 37 weeks' gestation for the measurement of umbilical venous blood plasma adenosine and catecholamine concentrations, blood gases, and pH.

RESULTS

In small-for-gestational-age fetuses plasma adenosine concentration was higher, umbilical venous PO2 and pH were lower, and PCO2 was significantly higher than in appropriate-for-gestational-age fetuses. The elevation of plasma adenosine concentration was inversely related to umbilical venous PO2 and pH.

CONCLUSION

Some small-for-gestational-age fetuses are exposed to diminished oxygen tension and acidotic blood gas values in utero. We postulate that the accompanying elevation of plasma adenosine may elicit protective adaptation during fetal asphyxia as a stress response.