Practical Radiation Oncology最新文献

Purpose: Accurate target delineation is essential when using intensity modulated radiation therapy for intact cervical cancer. In 2011, the Radiation Therapy Oncology Group published a consensus guideline using magnetic resonance imaging (MRI). The current project expands on the previous atlas by including computed tomography (CT)-based contours, contours with MRI and positron emission tomography (PET) registrations, the addition of common and complex scenarios, and incorporating information on simulation and treatment planning techniques.

Methods and materials: Twenty-eight experts in gynecologic radiation oncology contoured 3 cases, first on a noncontrast CT simulation scan and then with registered diagnostic scans. The cases included (1) International Federation of Gynecology and Obstetrics (FIGO) IIIC1 with a bulky tumor and vaginal metastasis, (2) FIGO IIB with calcified uterine fibromas, and (3) FIGO IIIC2 with large lymph nodes. The contours on all 6 data sets (3 CT simulations without diagnostic images and 3 with registered images) were analyzed for consistency of delineation using an expectation-maximization algorithm for simultaneous truth and performance level estimation with kappa statistics as a measure of agreement. The contours were reviewed, discussed, and edited in a group meeting prior to finalizing.

Results: Contours showed considerable agreement among experts in each of the cases, with kappa statistics from 0.67 to 0.72. For each case, diagnostic PET ± MRI was associated with an increase in volume. The largest increase was the clinical target volume (CTV) primary for case 2, with a 20% increase in volume and a 54% increase in simultaneous truth and performance level estimation volume, which may be due to variance in registration priorities. For the third case, 92.9% increased their CTVs based on the addition of the diagnostic PET scan. The main areas of variance were in determining the superior extent of CTV coverage, coverage of the mesorectum, and simulation and planning protocols.

Conclusions: This study shows the value and the challenges of using coregistered diagnostic imaging, with an average increase in volumes when incorporating MRI and PET.

Purpose: Heterotopic ossification (HO) is a benign disorder characterized by ectopic bone formation in soft tissues that can lead to functional loss in patients. We conducted a systematic review of the evidence on the use of radiation therapy (RT) for the prevention or treatment of HO.

Methods and materials: Literature searches were conducted using Medline (via PubMed), Embase, and ClinicalTrials.gov until April 1_, 2023. Medical subject headings and free text terms relevant to HO and RT were used. In brief, eligible study participants were ≥18 years of age with HO and were treated with low-dose external RT. Two reviewers screened relevant abstracts and extracted full-text data for analysis. The review followed the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines.

Results: Ten studies evaluating the effect of RT for either the prevention or treatment of HO met the inclusion for evidence synthesis. Nine randomized controlled trials did not clearly report their methods and had a medium risk of bias. The studies were conducted between 1988 and 2008, with follow-up ranging on average from 3 to 59 months posttreatment. A total of 1530 participants were analyzed, and 566 were treated with RT following fracture fixation, total hip arthroplasty, or total hip replacement. In pooled data from 8 randomized controlled trials, there was a nonsignificant but clinically meaningful reduction in the presence of HO at follow-up for patients who received RT versus comparators (pooled odds ratio, 0.47; 95% CI, 0.19, 1.17). There was minimal evidence of adverse events.

Conclusions: This systematic review found a clinically, but not statistically, significant benefit of prophylactic RT for HO at follow-up. These findings are tempered by a moderate risk of bias. While practice patterns vary, RT for HO prophylaxis in high-risk patients may have benefits that outweigh the risks.

Purpose: Despite the decades of using radiation therapy (RT) for Graves' ophthalmopathy, the effects and optimal timing remain unclear. We retrospectively analyzed to evaluate the overall efficacy and response, predictive factors, and the effective timing of RT by assessing steroid requirement after RT in patients without prior surgery.

Methods and materials: Between 2008 and 2022, we analyzed 74 patients with Graves' ophthalmopathy who received RT to both orbits. Concurrent steroid therapy was administered to 51 patients. Symptoms were evaluated using a modified clinical activity score (CAS), defining responders as those with a ≥2 score improvement in CAS, diplopia, or a significant reduction in exophthalmos asymmetry. Common symptoms included eye swelling (81.1%), and conjunctival edema (81.1%). Diplopia observed in 48 patients (64.9%).

Results: Median follow-up was 44.5 months (range, 4.8-169.6). CAS significantly improved in the early-immediate phase, 1 month after RT (P < .001). However, diplopia showed significant improvement at a relatively late phase, 4 months after RT (P = .039). Patients treated with steroids concurrently showed a faster response compared to those without steroids. Initiating RT within 12 months of symptom onset resulted in a shorter duration of steroid use after RT compared with later initiation (65 vs 286 days, P = .011).

Conclusions: Our study suggests an evaluation period of at least 4 months after RT regardless of concurrent steroid treatment, recognizing the prolonged improvement timeline for diplopia. Additionally, for reducing steroid use after RT, our study suggests optimal timing of RT within 12 months of symptom onset.

Purpose: Carbon fiber-reinforced polyetheretherketone (CFR-PEEK) instrumentation is being used more frequently in the spinal oncology landscape. Better visualization with this material allows for more precise postoperative stereotactic body radiation therapy (SBRT) planning using either computed tomography (CT)-myelography or magnetic resonance imaging (MRI) studies. We compared the dosimetric planning equivalencies and outcomes.

Methods and materials: Thirty-six consecutively treated patients were reviewed who underwent spinal fusion using CFR-PEEK instrumentation for spine metastases followed by postoperative SBRT between January 1, 2022, and April 3, 2023. Patients were divided into 2 cohorts based on the imaging modality, MRI versus CT-myelogram, used for postoperative SBRT planning. Surgical, demographic, postoperative radiation dosimetry, complication, and survival data were collected. Statistical analysis was performed in SPSS (v29.0.1.0).

Results: Eleven patients underwent CT-myelograms, and 25 patients underwent MR-spine imaging for SBRT planning. The median follow-up was 145.5 days (13-530). There were no significant differences between baseline demographic, surgical characteristics, or SBRT dosimetry between the MRI spine and CT-myelogram groups. There was no significant difference between the cohorts for survival (P = .402).

Conclusions: MR scans are an effective choice for postoperative SBRT contouring patients using CFR-PEEK instrumentation for oncologic spinal fusions. Avoidance of CT-myelography reduces the need for an invasive procedure and potential risks including cerebrospinal fluid (CSF) leak, nerve root injury, and increased procedural burden.

Low-dose chest computed tomography imaging for lung cancer screening is revealing increasing numbers of radiographic early-stage lung cancers. This topic discussion describes when a clinical scenario merits radiation therapy without a histologic diagnosis, with an emphasis on pragmatic algorithms in settings without readily available advanced biopsy techniques.

Purpose: To evaluate the feasibility and accuracy of focal boosting in online adaptive MRI-guided stereotactic body radiation therapy (SBRT) for patients with prostate cancer (PCa) with seminal vesicle invasion (T3b) by analyzing the impact of intrafraction motion on the dose planned for the gross tumor volume (GTV) and clinical target volume (CTV).

Methods and materials: Data from 23 patients with T1-T3a PCa who received focal boosting SBRT on a 1.5T MR-Linac was used. A radiation oncologist replaced clinical GTVs with artificial GTVs representative for T3b tumor(s). For each MRI used for daily adaptation (MRI_adapt), an automated treatment plan was generated (D_f1-5) using the adapted contours. Patients were planned to receive 35 Gy to the CTV, with an isotoxic focal boost to the GTV up to 50 Gy. During each fraction, an additional MRI was acquired to assess intrafraction motion (MRI_during). Dose accumulation of all fractions was performed by deformable registration of MRI_adapt, _f2-5 to MRI_adapt, _f1 (D_{ACC, planned})_. The D_f1-₅ were projected to their corresponding MRI_during, which were used to reconstruct D_{ACC, delivered}, likewise. Our results were compared to patients with tumor(s) without seminal vesicle invasion (T1-T3a).

Results: The median (10th-90th percentile) D98%_{ACC, planned} to the GTV, which correlates most strongly with outcome, was 41.1 Gy (40.1-43.0 Gy) in the plans for patients with artificial T3b tumors, compared to 43.0 Gy (40.4-47.2 Gy) in the plans for patients with T1-T3a tumors. The D98%_{ACC, delivered} to the GTV, taking into account intrafraction motion, was 41.0 Gy (39.3-42.6 Gy) and 42.5 Gy (40.0-46.6 Gy) in the plans for the artificial and clinical GTVs, respectively.

Conclusions: MRI-guidance can ensure high accuracy of focal boosting in patients with T3b disease. Because of the unfavorable location of the GTV, a lower boost dose was feasible compared to patients with T1-T3a PCa.

The use of neurostimulators has increased in recent decades. However, safety guidelines in patients undergoing radiation therapy (RT) are lacking. We report 2 cases of pelvic RT for prostate cancer in patients with spinal cord neurostimulators. The implantable pulse generator was placed close to the irradiated volume in the gluteal region and received a median and maximal dose of 2.8 and 5.68 Gy, respectively for patient 1; and 3.65 and 5.15 Gy, respectively for patient 2. During and after RT, No dysfunction of the device was recorded. Based on the similarity with the cardiac implantable electric devices, we recommend similar safety procedures, this include the following: (i) a cumulative dose <5 Gy, (ii) avoiding neutron-producing RT, (iii) ensuring the implantable pulse generator positioning outside the direct beams, (iv) switching the device to "off-mode" during treatment delivery, and (v) in vivo verification in case of implantable pulse generator close to irradiation volume. The final decision should involve neurology specialist.