After low and high dose-rate interstitial brachytherapy followed by IMRT radiotherapy for intermediate and high risk prostate cancer

Impact of neoadjuvant intensity-modulated radiation therapy on borderline resectable pancreatic cancer with arterial abutment; a prospective, open-label, phase II study in a single institution

Background

Borderline resectable pancreatic cancer (BRPC) is a category of pancreatic cancer that is anatomically widely spread, and curative resection is uncommon with upfront surgery. Intensity-modulated radiation therapy (IMRT) is a form of radiation therapy that delivers precise radiation to a tumor while minimizing the dose to surrounding normal tissues. Here, we conducted a phase 2 study to estimate the curability and efficacy of neoadjuvant chemoradiotherapy using IMRT (NACIMRT) for patients with BRPC with arterial abutment (BRPC-A).

Methods

A total of 49 BRPC-A patients were enrolled in this study and were treated at our hospital according to the study protocol between June 2013 and March 2021. The primary endpoint was microscopically margin-negative resection (R0) rates and we subsequently analyzed safety, histological effect of the treatment as well as survivals among patients with NACIMRT.

Results

Twenty-nine patients (59.2%) received pancreatectomy after NACIMRT. The R0 rate in resection patients was 93.1% and that in the whole cohort was 55.1%. No mortality was encountered. Local therapeutic effects as assessed by Evans classification showed good therapeutic effect (Grade 1, 3.4%; Grade 2a, 31.0%; Grade 2b, 48.3%; Grade 3, 3.4%; Grade 4, 3.4%). Median disease-free survival was 15.5 months. Median overall survival in the whole cohort was 35.1 months. The only independent prognostic pre-NACIMRT factor identified was serum carbohydrate antigen 19–9 (CA19-9) > 400 U/ml before NACIMRT.

Conclusions

NACIMRT showed preferable outcome without significant operative morbidity for BRPC-A patients. NACIMRT contributes to good local tumor control, but a high initial serum CA19-9 implies poor prognosis even after neoadjuvant treatment.

Trial Registration

UMIN-CTR Clinical Trial: https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000011776

Registration number: UMIN000010113.

Date of first registration: 01/03/2013,

Patient assessment of lower urinary tract symptoms using the international prostate symptom score following low-dose-rate prostate brachytherapy

PURPOSE

To correlate changes in urinary patient-reported outcomes including the International Prostate Symptom Score (IPSS), acute urinary retention and urethral stricture with urethral dose in those treated with low dose rate (LDR) prostate brachytherapy.

MATERIALS AND METHODS

Patients treated with prostate LDR between 2012 and 2019 (n=117) completed IPSS urinary symptom assessments prior to treatment and at each follow-up. CT simulation was obtained with urinary catheter 1-month post-implant for dosimetric analysis. 113 patients with pre- and ≥1 post-LDR IPSS score available were analyzed. Urethral dosimetric parameters including U75, U100, U125, U150 and U200 were abstracted from post-implant dosimetry and assessed for association with urinary toxicity using bivariate logistic regression and Spearman correlation. Outcomes included clinically significant change (CSC, defined as 4 or more points or 25% rise above baseline) in IPSS score at 6 and 12 months, acute urinary retention (AUR), and urethral stricture (US).

RESULTS

89 (79%) patients were treated with LDR monotherapy (145 Gy) and 24 (21%) with LDR boost (110 Gy) with external beam radiation therapy. Twenty (18%) had baseline IPSS ≥15. Median IPSS scores were: baseline 6 (3-12; n=113), 1-month 17 (10-25; n=110), 6 months 12 (7-18; n=77), 1 year 8 (5-14; n=52). CSC-6 was observed in 59 (77%), CSC-12 in 26 (50%), AUR in 12 (11%), and US in 4 (4%). No association was identified between urethral dose parameters and CSC-6, CSC-12, AUR, or US. No correlation between urethral dose and IPSS at 6- and 12-months was identified. The IPSS ≥15 group exhibited lower rates of CSC-12 (13% v. 57%, p=0.05) but not CSC-6 (55% v. 80%, p=0.12).

CONCLUSIONS

We did not find a relationship between urethral dose and IPSS elevation, AUR or US. We did identify a significantly lower change in IPSS at 12 months for those with baseline IPSS ≥15 compared to those with low baseline scores.

Neutron flux evaluation model provided in the accelerator-based boron neutron capture therapy system employing a solid-state lithium target

An accelerator-based boron neutron capture therapy (BNCT) system employing a solid-state Li target can achieve sufficient neutron flux for treatment although the neutron flux is reduced over the lifetime of its target. In this study, the reduction was examined in the five targets, and a model was then established to represent the neutron flux. In each target, a reduction in neutron flux was observed based on the integrated proton charge on the target, and its reduction reached 28% after the integrated proton charge of 2.52 × 10⁶ mC was delivered to the target in the system. The calculated neutron flux acquired by the model was compared to the measured neutron flux based on an integrated proton charge, and the mean discrepancies were less than 0.1% in all the targets investigated. These discrepancies were comparable among the five targets examined. Thus, the reduction of the neutron flux can be represented by the model. Additionally, by adequately revising the model, it may be applicable to other BNCT systems employing a Li target, thus furthering research in this direction. Therefore, the established model will play an important role in the accelerator-based BNCT system with a solid-state Li target in controlling neutron delivery and understanding the neutron output characteristics.

Characterization of the relationship between neutron production and thermal load on a target material in an accelerator-based boron neutron capture therapy system employing a solid-state Li target

An accelerator-based boron neutron capture therapy (BNCT) system that employs a solid-state Li target can achieve sufficient neutron flux derived from the ⁷Li(p,n) reaction. However, neutron production is complicated by the large thermal load expected on the target. The relationship between neutron production and thermal load was examined under various conditions. A target structure for neutron production consists of a Li target and a target basement. Four proton beam profiles were examined to vary the local thermal load on the target structure while maintaining a constant total thermal load. The efficiency of neutron production was evaluated with respect to the total number of protons delivered to the target structure. The target structure was also evaluated by observing its surface after certain numbers of protons were delivered. The yield of the sputtering effect was calculated via a Monte Carlo simulation to investigate whether it caused complications in neutron production. The efficiency of neutron production and the amount of damage done depended on the proton profile. A more focused proton profile resulted in greater damage. The efficiency decreased as the total number of protons delivered to the target structure increased, and the rate of decrease depended on the proton profile. The sputtering effect was not sufficiently large to be a main factor in the reduction in neutron production. The proton beam profile on the target structure was found to be important to the stable operation of the system with a solid-state Li target. The main factor in the rate of reduction in neutron production was found to be the local thermal load induced by proton irradiation of the target.

Dependence of neutrons generated by 7Li(p,n) reaction on Li thickness under free-air condition in accelerator-based boron neutron capture therapy system employing solid-state Li target

PURPOSE

An accelerator-based boron neutron capture therapy (BNCT) system with a solid-state Li target is reported to have degradation of the Li target. The degradation reduces the Li thickness, which may change spectra of the generated neutrons corresponding to the Li thickness. This study aims to examine the relationship between the Li thickness and the generated neutrons and to investigate the effects of the Li thickness on the absorbed dose in BNCT.

METHOD

The neutron energy spectra were calculated via Monte Carlo simulation for Li thicknesses ranging from 20 to 150 μm. Using the system, the saturated radioactivity of gold induced by reactions between ¹⁹⁷Au and the generated neutrons was evaluated with the simulation and the measurement, and those were compared. Additionally, for each Li thickness, the saturated radioactivity was compared with the number of generated neutrons. The absorbed doses delivered by ¹⁰B(n,α)⁷Li, ¹⁴N(n,p)¹⁴C, ¹H(n, g)²H, and (n,n') reactions in water were also calculated for each Li thickness.

RESULTS

The measurement and simulation indicated a reduction in the number of neutrons due to the degradation of the Li target. However, the absorbed doses were comparable for each Li thickness when the requisite number of neutrons for BNCT was delivered. Additionally, the saturated radioactivity of ¹⁹⁸Au could be a surrogate for the number of neutrons even if the Li thickness was varied.

CONCLUSIONS

No notable effect to the absorbed dose was observed when required neutron fluence was delivered in the BNCT even if the degradation of the Li was observed.

Long-term oncologic outcomes of radiotherapy combined with maximal androgen blockade for localized, high-risk prostate cancer

Background

To assess the oncologic outcomes of radiation therapy (RT) combined with maximal androgen blockade (MAB) and prostate-specific antigen (PSA) kinetics in patients with localized, high-risk prostate carcinoma (PCa).

Methods

Three-hundred twenty individuals with localized PCa who underwent RT + MAB in 2001–2015 were evaluated retrospectively. All patients had received 36 months of MAB therapy and 45 Gy of pelvic irradiation, plus a dose-escalated external beam radiation therapy (DE-EBRT) boost to 76~81 Gy (MAB + EBRT group), or a low-dose-rate prostate permanent brachytherapy (LDR-PPB) boost to 110 Gy with I-125 (MAB + EBRT + PPB group).

Results

Follow-up median is 90 months, ranging from 12 to 186 months; 117 (36.6%) and 203 (63.4%) cases underwent MAB + EBRT and MAB + EBRT + PPB, respectively. Multivariate Cox regression showed that the PPB regimen and PSA kinetics were positive indicators of oncologic outcomes. Compared with MAB + EBRT, MAB + EBRT + PPB remarkably improved PSA kinetics more pronouncedly: PSA nadir (1.3 ± 0.7 vs 0.11 ± 0.06 ng/mL); time of PSA decrease to nadir (7.5 ± 1.8 vs 3.2 ± 2.1 months); PSA doubling time (PSADT; 15.6 ± 4.2 vs 22.6 ± 6.1 months); decrease in PSA (84.6 ± 6.2% vs 95.8 ± 3.4%). Additionally, median times of several important oncologic events were prolonged in the MAB + EBRT + PPB group compared with the MAB + EBRT group: overall survival (OS; 12.3 vs 9.1 years, P < 0.001), biochemical recurrence-free survival (BRFS; 9.8 vs 6.5 years, P < 0.001), skeletal-related event (SRE; 10.4 vs 8.2 years, P < 0.001), and cytotoxic chemotherapy (CCT; 11.6 vs 8.8 years, P = 0.007).

Conclusion

MAB + EBRT + PPB is extremely effective in patients with localized, high-risk PCa, indicating that PPB may play a synergistic role in improving PSA kinetics and independently predicts oncologic outcomes.

Synchronous multiple primary gallbladder and gastric malignancies: Report of two cases and review of the literature

Multiple primary malignancies (MPM) are rare. In particular, synchronous gallbladder and gastric malignancies are extremely rare, are associated with a concealed onset and atypical symptoms, and are highly likely to be overlooked or misdiagnosed. The clinical data of two patients with synchronous gallbladder and gastric malignancies are herein reported and integrated with the relevant literature to retrospectively analyze and summarize the pathogenesis and clinical characteristics of MPM. Case 1 was a male 46-year-old patient who underwent laparoscopic cholecystectomy, and succumbed to extensive tumor metastasis 2 months after the operation. Case 2 was an 80-year-old female patient who was treated with distal gastrectomy for gastric cancer, cholecystectomy, gastrojejunostomy and dissection of 5 suprapyloric, 6 subpyloric, 7 left gastric and 8 common hepatic artery lymph nodes, and succumbed to multiple organ failure induced by extensive tumor invasion within 1 week after the operation. Clinical physicians must pay closer attention to early symptoms of MPM in order to make an accurate diagnosis, perform timely radical surgical treatment and achieve favorable therapeutic outcomes, in terms of significantly increasing long-term patient survival rates.

[Focal dose escalation in the treatment of prostate cancer : Long-term results of HDR brachytherapy]

BACKGROUND

We prospectively examined the effect and the safety of intensity-modulated HDR brachytherapy (IMBT) with focal dose escalation.

MATERIALS AND METHODS

A total of 139 patients undergoing primary therapy for prostate cancer and 11 patients with recurrence were included. Data analysis focused on the following factors: date of primary diagnosis, Gleason score, initial prostate-specific antigen (PSA) value, PSA nadir, volume of the prostate in the transrectal ultrasound, biopsy of the prostate gland, androgen deprivation, chemotherapy, uroflowmetry, pre- and postoperative post-void residual urine (PVR), number of the needles in the prostate lobes and analysis of follow-up data.

RESULTS

In the primary therapy group, 87.6 % of the patients had a PSA of 0-4 ng/ml at the time of follow-up, while in the recurrence group 81.8 % of patients were within this range. Overall, 55.8 % of patients in the primary group had a PSA nadir under 0.1 ng/ml, 37.2 % under 1 ng/ml, 5.8 % under 5 ng/ml and 1.2 % (1 patient) over 5 ng/ml. In the recurrence group, 100 % had a PSA nadir under 0.1 ng/dl. Fifty patients of the primary group reported grade 1 toxicity (Common Toxicity Criteria): 29 localized to the bladder and 21 to the rectum. Seventeen patients had grade 2 toxicity of the bladder and 1 patient had grade 3 toxicity of the bladder. Finally there was one grade 4 toxicity due to perforation of the sigmoid colon. In the recurrence group, 3 patients with grade 1 toxicity were observed (2 bladder and 1 bowl). Also 3 patients had grade 2 toxicity of the bladder, 1 patient had a grade 3 bladder toxicity and 1 patient had grade 4 toxicity due to bowl fistula. There were no grade 5 toxicities.

CONCLUSION

The modifications of the "Kiel method" with focal dose escalation was proven as effective in locally advanced prostate carcinoma and in local recurrences of the disease with low level toxicity.