Upper rectal fixation with an endorectal balloon in prostate cancer radiotherapy.

Purpose: Despite the efficacy of endorectal balloon (ERB) in reducing rectal radiation dose, the effectiveness of upper rectal fixation remains to be evaluated. The purpose of this study was to evaluate the impact of ERB on upper rectal fixation in patients diagnosed with localized prostate cancer. Materials: Cine MRI was performed in 46 patients with localized prostate cancer to assess the stability of the anterior rectal wall with and without ERB by calculating the standard deviation of the normalized signal intensity at the level of the midgland or the seminal vesicle. Results: The standard deviation of the normalized signal intensity for the anterior rectal wall decreased significantly with the use of ERB both at the level of the midgland (p < 0.05) and the seminal vesicle (p < 0.05). The standard deviation of the anterior rectal wall at the level of the seminal vesicle was significantly higher than at the level of the midgland without ERB (p < 0.05). But with ERB, the standard deviation of the normalized signal intensity at the level of the seminal vesicle became comparable to that at the level of the midgland (p = 0.392). Conclusion: The anterior rectal wall is stabilized by ERBs not only at the level of the midgland but also at the level of the seminal vesicle. ERBs can transform the rectum from a moving and deformable organ into a static and rigid organ.

High-dose planned adaptive helical tomotherapy for cutaneous angiosarcoma of the scalp.

PURPOSE: The purpose of this study was to investigate the feasibility and effectiveness of high-dose planned adaptive intensity-modulated radiation therapy (IMRT) with helical tomotherapy (HT) for cutaneous angiosarcoma (cAS) of the scalp. METHODS: This retrospective cross-sectional included a total of 12 consecutive patients with cAS of the scalp who underwent high-dose planned adaptive IMRT with HT. Prescribed doses were 72.5-74 Gy in 35-37 fractions for the gross tumor volume plus a 1-2 mm margin (PTV1), 58-60 Gy in 29-30 fractions for the clinical target volume plus a 2-3 mm margin (PTV2), and 46 Gy in 23 fractions for the clinical target volume plus a 5-15 mm margin (PTV3) over periods of 7.5, 6 and 4.5 weeks, respectively. RESULTS: The estimated 1­year and 2­year overall survival rate were 65.6% and 27.3%, respectively, and the local progression-free survival at 2 years was 74.1%. All local recurrences were either in or marginal to the PTV2 or PTV3. No local recurrence was observed in the PTV1. All patients tolerated the treatment without grade 3 or higher adverse events during the radiotherapy period. No late adverse events were observed during the follow-up period. CONCLUSION: Planned adaptive high-dose IMRT with HT has the potential to improve local control rate without increasing adverse events.

MRI findings of iatrogenic extravasation of gadolinium-based contrast agents in patients with cancer.

BACKGROUND: Magnetic resonance imaging (MRI) findings after subcutaneous extravasation of gadolinium-based contrast agent (GBCA) have not been investigated in detail. PURPOSE: To present the MRI findings of iatrogenic extravasation and to evaluate the characteristic findings. MATERIAL AND METHODS: In this retrospective study of 16,039 patients with cancer, 11 patients had significant extravasation of macrocyclic GBCA, and 7 of the 11 had MRI of the injection site. Characteristic MRI findings as well as symptoms and changes over time were evaluated. RESULTS: The forearms or antecubital fossa felt cold in all seven cases, and 3 (43%) patients felt pain at the injection sites. Fat-suppressed T1-weighted images showed a mosaic pattern of the extravasate with mixed high and low signal in the subcutaneous tissue in 7 (100%) cases. Contrast enhancement of the fascia toward the proximal portion was observed in 3 (43%) cases. There was no subfascial deep extension. On T2-weighted images, GBCAs were observed as low-signal fluid collection on the fascia, with linear spread to the dermis and subcutaneous tissue. Four patients underwent daily MRI scans, all of whom had their contrast disappeared within three days. CONCLUSION: Macrocyclic GBCA disappears from subcutaneous tissue quickly after extravasation and is unlikely to cause serious sequelae.

Long-term follow-up results of endorectal balloon-assisted helical tomotherapy for localized prostate cancer patients in the high-risk group of gastrointestinal adverse events.

Background: Endorectal balloon (ERB) has been shown to reduce rectal radiation dose and late gastrointestinal toxicities in patients with prostate cancer. However, the usefulness of ERBs for patients with prostate cancer whose rectal shape or size is suboptimal has not been investigated. The purpose of this study was to present the long-term follow-up results of ERB-assisted helical tomotherapy for localized prostate cancer patients whose initial radiation treatment planning (RTP) was unacceptable due to suboptimal rectal shape or size. Materials and methods: Of 541 consecutive patients with localized prostate cancer, 10 were included in this study whose RTPs without ERBs did not meet dose constraints due to: 1) Intestinal intrusion, 2) Small rectum; or 3) Unstable rectal shape. We re-planned using ERBs and delivered 76 Gy in 38 fractions, and evaluated the long-term usefulness and safety of ERB-assisted helical tomotherapy. Results: At a median follow-up of 109 months, there were no local recurrences of prostate cancer. The overall, cause-specific, and progression-free survivals at 10 years were 90.0%, 100%, and 83%, respectively. Adverse events of grade 3 or higher were not observed during or after ERB-assisted helical tomotherapy. Conclusions: When intestinal intrusion, a small rectum, or an unstable rectal shape is an obstacle for administering helical tomotherapy, ERBs might be the solution.

MRI-guided stereotactic ablative radiation therapy for liver metastasis from pancreatic cancer.

A 69-year-old man with a history of pancreatic cancer was referred to our hospital for a newly developed solitary liver metastasis. Since the liver metastasis was in contact with the small intestine, it was necessary to perform radiation therapy while simultaneously monitoring the small intestine and liver metastasis, and then, MRI-guided stereotactic ablative radiation therapy (SABR) was performed. There were no radiation-induced adverse events during the treatment and 6 months of follow-up. MRI showed complete regression of the tumor at 6 months after SABR. It seems feasible to perform SABR safely by using MRI-guided radiation therapy system even if liver metastasis developed near the intestinal tract after surgery for pancreatic cancer.

Quantitative evaluation of volume change of perirectal hydrogel spacer by Dixon-based water-only images.

Purpose: There are no detailed data on volume changes of SpaceOAR hydrogel spacer. The purpose of this study was to quantitatively evaluate the volume changes of SpaceOAR during radiation therapy for prostate cancer. Materials: The volume of SpaceOAR in seven prostate cancer patients was quantitatively measured every two weeks by Dixon-based water-only MRI scans. Results: The volume of SpaceOAR increased and remained increased for 11 weeks after placement in all cases. The day to reach the maximum volume was 49.9 +/- 9.2 (mean +/- standard deviation [SD]) days after placement. The maximum rate of increase in Space OAR volume was 20% +/- 9% (mean +/- SD). Conclusions: The volume of SpaceOAR was shown to be greater than the initial volume for 11 weeks after placement, with an increase of up to 20%. Therefore, care should be taken when creating a radiation treatment planning and positioning a patient during radiation therapy.

Clinical adoption patterns of 0.35 Tesla MR-guided radiation therapy in Europe and Asia.

BACKGROUND: Magnetic resonance-guided radiotherapy (MRgRT) utilization is rapidly expanding, driven by advanced capabilities including better soft tissue imaging, continuous intrafraction target visualization, automatic triggered beam delivery, and the availability of on-table adaptive replanning. Our objective was to describe patterns of 0.35 Tesla (T)-MRgRT utilization in Europe and Asia among early adopters of this novel technology. METHODS: Anonymized administrative data from all 0.35T-MRgRT treatment systems in Europe and Asia were extracted for patients who completed treatment from 2015 to 2020. Detailed treatment information was analyzed for all MR-linear accelerators (linac) and -cobalt systems. RESULTS: From 2015 through the end of 2020, there were 5796 completed treatment courses delivered in 46,389 individual fractions. 23.5% of fractions were adapted. Ultra-hypofractionated (UHfx) dose schedules (1-5 fractions) were delivered for 63.5% of courses, with 57.8% of UHfx fractions adapted on-table. The most commonly treated tumor types were prostate (23.5%), liver (14.5%), lung (12.3%), pancreas (11.2%), and breast (8.0%), with increasing compound annual growth rates (CAGRs) in numbers of courses from 2015 through 2020 (pancreas: 157.1%; prostate: 120.9%; lung: 136.0%; liver: 134.2%). CONCLUSIONS: This is the first comprehensive study reporting patterns of utilization among early adopters of a 0.35T-MRgRT system in Europe and Asia. Intrafraction MR image-guidance, advanced motion management, and increasing adoption of on-table adaptive RT have accelerated a transition to UHfx regimens. MRgRT has been predominantly used to treat tumors in the upper abdomen, pelvis and lungs, and increasingly with adaptive replanning, which is a radical departure from legacy radiotherapy practices.

The Long-Term Effect of Intensity Modulated Radiation Therapy for Prostate Cancer on Testosterone Levels.

Purpose: Concern about a long-term effect of the delivery of intensity modulated radiation therapy (IMRT) for prostate cancer on serum testosterone levels remains unelucidated. We evaluated how IMRT for localized prostate cancer affects serum testosterone levels during a follow-up period of up to 10 years. Methods and Materials: We retrospectively evaluated data from 182 patients with localized prostate cancer who underwent definitive IMRT alone between 2007 and 2014. Serum total testosterone (TT) levels were measured by blood draws between 6 AM and 11 AM before treatment and at every posttreatment follow-up for 10 years. Pretreatment values and each posttreatment testosterone value were compared using a Wilcoxon signed rank test. The data set was stratified into 4 groups based on the pretreatment testosterone (pre-TT) values using quartiles. Results: The median absolute or relative changes in TT levels from pretreatment were -0.42 ng/mL or -12.0% at 3 months after radiation therapy (P < .0001). Subsequently, TT levels gradually recovered to nearly the pretreatment levels 24 to 36 months after IMRT. When analyzed according to the pre-TT quartile, median TT levels initially decreased at the 3- to 12-month period in all the quartiles; however, median TT levels increased from the 18-month period in the first and second quartile groups, whereas they were maintained at less than the pretreatment levels in the third and the fourth quartile groups throughout the entire decade after radiation therapy. The proportion of patients with hypogonadal status, defined as TT levels <3.00 ng/mL, did not increase over time. Conclusions: A transient and modest decrease of TT levels after IMRT spontaneously recovered to the pretreatment levels at the 24- to 36-month period except in patients in the higher quartile of pre-TT. This might have been partly owing to a variable sensitivity of individual testicular function to scattered radiation. Patients with lower pre-TT did not demonstrate a progressive overall rate of hypogonadism until 10 years after radiation therapy.

SPIO-enhanced 0.35T MRI-guided radiotherapy for liver malignancies: usefulness in tumor visualization.

OBJECTIVES: The purpose of this study was to investigate the changes of tumor-to-liver signal ratio in a 0.35T MRI-guided radiotherapy system and to evaluate the usefulness and pitfalls of superparamagnetic iron oxide (SPIO) administration for visualization of liver tumors. METHODS: Forty-two patients treated with MRI-guided stereotactic ablative radiotherapy (SABR) for liver tumors were included in this study. The tumor-to-liver signal ratios before and after SPIO administration were retrospectively assessed and compared on true fast imaging with steady-state precession (FISP). RESULTS: Before SPIO administration, liver tumors were either invisible or barely visible in 15 cases (36%), but all tumors became visible after SPIO administration. The mean values of tumor-to-liver signal ratio before and after SPIO administration were 0.939 ± 0.201 and 1.336 ± 0.300, respectively (mean ± standard deviation, p < 0.001). In six (14%) patients, liver tumors were visible on true FISP imaging before SPIO administration, but became invisible after administration. CONCLUSIONS: This study showed that liver tumors that are invisible on true FISP imaging can be made visible by administration of SPIO, and that MRI-guided SABR can be performed accurately. ADVANCES IN KNOWLEDGE: This is the first report to examine the usefulness of liver-specific contrast agent superparamagnetic iron oxides in 0.35T MRI-guided radiation therapy. Liver tumors that are invisible on true fast imaging with steady-state precession can be made visible by administration of superparamagnetic iron oxides.

High-Dose Planned Adaptive Intensity-Modulated Radiation Therapy with Simultaneous Integrated Boost for Synchronous Oligometastatic Pancreatic Cancer.

The purpose of this study was to investigate the efficacy and feasibility of high-dose (72.6 Gy) planned adaptive intensity-modulated radiation therapy (IMRT) with simultaneous integrated boost (SIB) for 9 consecutive patients with synchronous oligometastatic pancreatic ductal adenocarcinoma (PDAC). The estimated 2-year overall survival rate was 66.7%, and the local progression-free survival at 2 years was 83.3%. No severe adverse events were observed. Planned adaptive dose-escalated IMRT-SIB has the potential to improve local control rate and prolong overall survival in patients with synchronous oligometastatic PDAC.

Multiparametric MRI-guided Hypofractionated Intensity-modulated Radiation Therapy With Simultaneous Integrated Boost for Glioblastoma.

BACKGROUND/AIM: This study investigated the feasibility and efficacy of multiparametric magnetic resonance imaging (MRI)-guided dose-escalated hypofractionated intensity-modulated radiation therapy with simultaneous integrated boost (IMRT-SIB) for glioblastoma. PATIENTS AND METHODS: Eighteen patients underwent postoperative IMRT-SIB for glioblastoma using three MRI sequences: double inversion recovery (DIR), diffusion tensor imaging (DTI), and post-gadolinium T1-weighted imaging. Prescribed doses were 60 Gy and 40 Gy in 15 fractions for residual enhancing lesions and surrounding tumor-infiltrating areas, respectively. For surrounding tumor-infiltrating areas, asymmetric margins were set with reference to DTI imaging. RESULTS: The 1-year overall survival rate was 58.0%, and the 1-year local control rate for the residual enhancing lesions was 76.2%, while that for surrounding tumor-infiltrating areas was 39.4%. One patient (6%) developed grade 2 cerebral radiation necrosis 10 months after IMRT-SIB, but there was no grade 3 or higher adverse event. CONCLUSION: Multiparametric MRI-guided dose-escalated IMRT-SIB with DIR and DTI imaging has the potential to improve local control rates without increasing adverse events.

Superparamagnetic iron oxide-enhanced MRI-guided stereotactic ablative radiation therapy for liver metastasis.

BACKGROUND: MRI-guided radiation therapy can image a target and irradiate it at the same time. Superparamagnetic iron oxide (SPIO) is a liver-specific contrast agent that can selectively visualize liver tumors, even if plain MRI does not depict them. The purpose of this study was to present a proof of concept of SPIO-enhanced MRI-guided radiation therapy for liver tumor. CASE PRESENTATION: MRI-guided stereotactic ablative radiation therapy (SABR) was planned for a patient with impaired renal function who developed liver metastases after nephroureterectomy for ureteral cancer. Because liver metastasis was not visualized on plain MRI, SPIO-enhanced MRI was performed at 0.35 T using true fast imaging with steady-state free precession (true FISP) pulse sequence and SABR was performed. Liver metastasis was clearly visualized by SPIO-enhanced MRI, and MRI-guided SABR was performed without adverse events. CONCLUSION: Even if liver metastasis is not visualized by plain MRI, liver metastasis can be clearly depicted by administering SPIO, and MRI-guided radiation therapy can be performed.

Comparison of gross tumor volumes of pulmonary metastasis defined by CT and MRI in 0.345 T MRI-guided radiotherapy.

OBJECTIVE: To assess the difference in gross tumor volumes (GTVs) defined by CT (GTV-CT) and by low magnetic field strength (0.345 T) MRI (GTV-MRI) in patients simulated for MRI-guided radiotherapy forlung metastasis. METHODS: 28 patients (148 lesions) who underwent CT and MRI simulation with the tri-60Co MRI-guided radiotherapy system (MRIdian, ViewRay) were included in this study. GTV-CT and GTV-MRI were compared using the paired t-test. The equivalence of variance between GTV-CT and GTV-MRI of small lesions (GTV-CT <1 ml) and large ones (GTV-CT >= 1 ml) was evaluated using F-test. The correlation between GTV-CT and GTV-MRI was evaluated by the correlation coefficient. RESULTS: GTV-MRI was 120% larger than GTV-CT (p < 0.001) for small lesions, whereas GTV-MRI was 40% larger than GTV-CT (p < 0.001) for large lesions. In small lesions, the variation in GTV-MRI was significantly larger than that of GTV-CT (p < 0.001). There was no significant difference in the variation of GTV-MRI and GTV-CT in large lesions (p = 0.121). The correlation coefficient for small lesions was 0.93, whereas that for large lesions was 0.99, with large lesions having better correlation. CONCLUSIONS: GTV-MRI was larger than GTV-CT and the correlation between GTV-MRI and GTV-CT was better in large lesions. If the tumor volume is 1 ml or larger, the lesion can be accurately monitored even with a low magnetic field strength MRI. ADVANCES IN KNOWLEDGE: This study is the first clinical report to evaluate the tolerability of MRI images in 0.345 T MRI-guided radiotherapy for lung metastasis. GTV contoured by MRI was larger than GTV by CT, and this tendency was more pronounced in small tumors of less than 1 ml.

Pancytopenia due to massive bone marrow carcinomatosis after radiotherapy for locally advanced breast cancer.

Pancytopenia is a rare complication among patients with breast cancer. Here, we report a case of pancytopenia due to massive bone marrow carcinomatosis (BMC) developed after local radiotherapy following to mastectomy. A 48-year-old woman with locally advanced breast cancer underwent mastectomy and axillary lymph node dissection. During adjuvant chemotherapy, rapidly growing supraclavicular lymph node metastasis was noted, so chemotherapy was discontinued and local radiotherapy was performed. There was no myelosuppression or systemic metastases prior to radiotherapy, but 2 weeks after the completion of radiotherapy, complete blood counts showed pancytopenia, and chest CT scans revealed multiple bone metastasis. A bone marrow biopsy was performed and massive BMC was diagnosed. Despite the best supportive care, her disease progressed rapidly and she died 2 months after radiotherapy. Locally advanced breast cancer that is resistant to chemotherapy is at risk of early fatal BMC and should be carefully monitored.

Long-term Follow-up Results of CT-guided Daily Adaptive Radiation Therapy for Localized Prostate Cancer.

BACKGROUND/AIM: To examine whether CT-guided daily adaptive radiation therapy (ART) can be safely administered against localized prostate cancer. PATIENTS AND METHODS: Twenty-six patients with localized prostate adenocarcinoma were irradiated through opposed AP/PA fields up to 46 Gy, then CT-guided daily ART was performed through opposed lateral fields until 76 Gy at 2 Gy/fraction. RESULTS: Biochemical relapse-free survival was 89% at 3 years and 85% at 5 years and 76% at 7 years after ART, respectively. The 3-, 5- and 7-year local relapse-free survival rates were 100%, 100% and 95%, respectively. The 5-year incidence rates of grade 1 and 2 late gastrointestinal adverse events were 15.4% (n=4) and 3.8% (n=1), respectively, and those of grade 1 and 2 late genitourinary adverse events were 3.8% (n=1) and 0% (n=0), respectively. CONCLUSION: CT-guided daily ART was well tolerated and suggested a good long-term tumor control with minimal adverse events.

Locally advanced pancreatic cancer successfully treated with high-dose helical tomotherapy.

Complete surgical resection is the potentially curative treatment for pancreatic cancer, but only fewer than 20% of those individuals will be found to be eligible for surgery. Here we report a 49-year-old man with locally advanced pancreatic cancer successfully treated with high-dose radiotherapy using helical tomotherapy (66 Gy/33 fractions, 2 Gy per day over 6.5 weeks). To our knowledge, this is the first reported case of locally advanced pancreatic cancer curatively treated with helical tomotherapy alone.

Exacerbation of gemcitabine-related pneumonia during radiotherapy for extrapulmonary lesion.

Late-onset gemcitabine pulmonary toxicity is rare and association between pulmonary toxicity and radiotherapy to the extrapulmonary sites is controversial. Here, we report a case of acute exacerbated fatal interstitial pneumonia during radiotherapy to the extrapulmonary site. A 73-year-old woman with pelvic lymph node metastases from urothelial carcinoma underwent palliative radiotherapy after failure of gemcitabine-containing and gemcitabine-non-containing chemotherapy. Gemcitabine-containing chemotherapy had finished 13 months prior to the radiotherapy due to grade 3 pulmonary toxicity. During the course of radiotherapy to the pelvic lesion, she was complicated with fatal acute interstitial pneumonia even though the lung tissue was not irradiated. To the best of our knowledge, this is the first reported case of fatal gemcitabine-related pulmonary toxicity during radiotherapy for extrapulmonary lesion. Although the association between late-onset pulmonary toxicity and radiotherapy is controversial, caution should be paid to a patient with a history of gemcitabine-related pulmonary toxicity who will undergo radiotherapy even though the lung volume is not irradiated.

Sporadic Burkitt's lymphoma of the axilla: CT and MR imaging findings.

Burkitt's lymphoma (BL) is a high-grade B-cell non-Hodgkin's lymphoma, which can be divided into endemic, sporadic and human immunodeficiency-associated subtypes. The sporadic BL typically presents as an intra-abdominal tumour but that of cutaneous or subcutaneous origin is very uncommon. We present a case of sporadic BL arising from the axillary soft tissue and discuss the CT and MRI findings.

Detection of prostate calcification with megavoltage helical CT.

RATIONALE AND OBJECTIVES: Prostate calcification is a noninvasive landmark for daily positioning of image-guided radiation therapy. However, detectability of prostate calcification with megavoltage helical computed tomography (MVCT) has not been evaluated. The purpose of this study was to evaluate the detectability of prostate calcification and to investigate how to predict detectability of calcification with MVCT. MATERIALS AND METHODS: Thirty patients with prostate cancer who were scheduled for helical tomotherapy were included in this study. The detectability of prostate calcification on MVCT was evaluated by comparing against kilovoltage multidetector-row CT (KVCT) as the standard of reference. Maximum signal intensity (SImax), area (A) of calcification, and the product of both (SImax·A) were compared between undetectable and detectable calcifications. Then, the threshold values of SImax, A, and SImax·A were decided to achieve 100% sensitivity on MVCT. RESULTS: KVCT identified 49 calcifications in 28 of 30 patients. MVCT detected 19 (39%) of 49 calcifications in 15 (50%) of 30 patients. The minimum threshold values of SImax, A, and SImax·A to detect prostate calcifications were 953 HU, 20.98 mm(2), and 7784 HU mm(2), respectively. Using the threshold values of SImax, A, and SImax·A, 20% (10/49), 18% (9/49), and 35% (17/49) of calcifications were in the detection range, respectively. CONCLUSIONS: MVCT can depict about one-third of prostate calcifications detectable on KVCT. The product of maximum signal intensity and area of calcification is the most distinguishable index for predicting patients showing prostate calcifications on MVCT.

Antitumor effect of 89Sr for multiple bone metastases of breast cancer: diagnosis by 18F-FDG PET/CT.

89Sr is useful for the palliation of painful bone metastasis, but its antitumor activity as a monotherapy has not been shown by 18F-FDG PET. Here, we report a case of a 75-year-old woman with multiple bone metastases of breast cancer in which 18F-FDG PET demonstrated a significant reduction in uptake of 18F-FDG after administration of 89Sr.