Practical Radiation Oncology最新文献

Background and purpose: In rectal cancer, accurate delineation is crucial for patients with enlarged lateral lymph nodes to minimize lateral local recurrence risk. This study aims to evaluate inter-physician variation in delineation of the lateral compartments, and the impact of training and implementation of standardized delineation protocols.

Methods: Twenty-three radiation oncologists from 15 institutes delineated the clinical target volume (CTV) on CT-scan in one example of a patient with rectal cancer. Parallel to this, the national consensus guideline was updated. Participating radiation oncologists completed an e-learning and online training session. Subsequently, 12 radiation oncologists re-delineated the same case. Variation was measured with the Dice-score and 95% Hausdorff distance.

Results: Considerable inter-physician variation was present before guideline distribution; and larger in the anterior compartment than the posterior compartment (Dice score 0.66 vs 0.80, p<0.01). After training, there was a significant improvement in 95% Hausdorff distance for the lateral compartments together (0.71 vs 1.02, p=0.02), but not in Dice score (0.76 vs 0.78, p=0.31), and neither for the anterior and posterior compartment separately. While delineation variation in the ventral and lateral sides decreased, the variation in the caudal side of the anterior compartment increased.

Conclusion: Substantial delineation variation in CTV of the lateral compartments in rectal cancer cases exists. This can be reduced by implementation of a delineation guideline with clear anatomical borders and subsequent training. Despite reduction in 95% Hausdorff distance, there is still need for further improvement in specific areas to assure adequate delineation.

Purpose: The implications of margin expansions on local control(LC) and radionecrosis(RN) for treating brain metastases with stereotactic radiosurgery(SRS) remain unclear. We performed a systematic review and meta-analysis to compare LC and RN between patients with brain metastases treated with stereotactic radiosurgery(SRS) planned with no margin vs. a margin.

Methodology: We utilized PICOS/PRISMA/MOOSE selection inclusion criteria for studies of patients with brain metastases treated with SRS with no margin or a margin. Primary outcomes were 1-year LC and radiographic and symptomatic RN incidences. Weighted random effects meta-analyses were performed to compare effect sizes.

Results: Across 17 studies, we identified 5,015 lesions treated with SRS (1,360 lesions with no margin and 3,684 with a margin). The median total margin was 1.5 mm (range: 1-3). Single fraction SRS was most common with a median prescription dose of 21 Gy (range: 15-24 Gy). The estimated 1-year LC rate was similar with a margin (88.4% (95% CI: 83.7-92.4%) vs. without (83.0% (95% CI: 69.3-93.2%; p = 0.28)). Estimated incidences of radiographic RN following SRS with no margin vs. a margin were similar at 9.2% (95% CI: 0.2-29.6%) and 7.0% (95% CI: 4.1-10.7%; p=0.56), respectively. Estimated incidences of symptomatic RN following SRS with no margin vs. with a margin were 8.6% (95% CI: 5.2-12.7%) and 4.1% (95% CI: 0.9-9.3%), respectively (p=0.24).

Conclusions: Significant differences were not noted in either LC or RN for patients treated with margin expansions vs. without. Prospective evaluations are warranted to further assess this question while controlling for other relevant treatment planning and metastasis considerations.

Aim: To assess the dosimetric results of an online adaptive stereotactic body radiotherapy (SBRT) program to treat patients with prostate cancer using a conventional linear accelerator.

Methods and materials: Prostate SBRT with five fractions is performed at the XXXX using an online adaptive method previously described (XXXX). A CBCT based adaptive "plan-of-the-day" (POD) is generated for each treatment fraction, which consists of a single volumetric modulated arc therapy. A dosimetric evaluation of the PODs was performed for the first twenty patients and included analysis of the target (prostate), organs-at-risks (OARs), and patient-specific quality assurance (PSQA). Each of the PODs was also compared with the corresponding conventional image-guided radiotherapy (IGRT) method. Finally, the adaptive treatment timing is analyzed for the one hundred PODs in this study RESULTS: The online adaptive treatment method ensured optimal target coverage in all treatment fractions for all patients. However, the simulated IGRT plans did not result in adequate prostate coverage (V40 Gy ≥ 95%) in 70% of fractions. Small average differences between PODs and IGRT plans were found in the OARs. The dose sparing in the rectum and bladder provided by some simulated IGRT plans, was associated with a compromised prostate coverage. The PSQA resulted in an excellent agreement between the online-calculated plans and the independent dose checks performed for all one hundred PODs. The average duration of the plan adaptation was 20.1 ± 6.1 minutes and the average overall session time including adaptation and treatment delivery was 26.4 ± 33.2 minutes.

Conclusions: This study demonstrates The online adaptive program using a conventional linac to treat prostate cancer described in this study is clinically feasible and in adherence with the acceptance criteria set by the PACE B.

Trial:

Background and purpose: Elective nodal irradiation (ENI) in resectable pancreatic cancer remains undefined, though occult nodal disease is common. This study investigated the use of neoadjuvant stereotactic body radiation therapy (SBRT) to primary disease with ENI, with concurrent capecitabine. Safety data for this protocol were previously reported. In this report, we provide an updated survival analysis.

Materials and methods: This is a prospective, single institution, phase IA/B dose-escalation trial that enrolled patients with biopsy-proven, resectable, pancreatic adenocarcinoma between 2014 - 2019 (NCT1918644). Patients were enrolled into one of the 3 cohorts with escalating dose levels. Neoadjuvant SBRT to the primary tumor was delivered in 5 fractions of 5, 6, or 7 Gy with concomitant capecitabine (1650 mg/m2). All patients received ENI 5 Gy x 5 fractions. Our initial report found no dose-limiting toxicities. Clinicopathologic features were summarized using descriptive statistics. Kaplan-Meier (KM) curves were employed for survival analysis.

Results: Of 17 enrolled patients, 16 were evaluable (94.1%). Thirteen (76.5%) proceeded to surgery. Median follow up was 28.0 months (1.7 - 71.9). Four patients (25.0%) received neoadjuvant chemotherapy and six (37.5%) received adjuvant chemotherapy. Pathologic nodal involvement (69.2%) was associated with a higher risk of any relapse (p<0.01) and distant metastasis (p=0.02). Local failure occurred in 4 (25%) patients with 2/4 of those failures occurring partially within the 25 Gy elective nodal field and 1/4 occurred in the 25 Gy elective nodal field and partially within the 35 Gy tumor field. The median overall survival (OS) and disease-free survival (DFS) were 31.1 months (range, 2.3 - 73.6) and 12.0 months (range, 0.4 - 71.9), respectively. Three-year OS and DFS were 50% and 31.3% overall, and 61.5% and 38.5% for the surgical cohort. Patients with pN+ had worse median OS (23.9 vs 69.3 months; p=0.002) and DFS (9.9 vs 58.9 months; p=0.002). No further radiation related toxicities were noted since the prior report.

Conclusion: Neoadjuvant SBRT to the primary tumor with ENI and radiosensitizing chemotherapy is a feasible approach that may improve outcomes in patients with resectable and borderline pancreatic cancer, despite high rates of pathological nodal involvement. Further investigation of this strategy is warranted in a larger cohort.

Purpose: Vestibular schwannomas (VS) are the most common benign intracranial nerve sheath tumors. Surgery and radiotherapy - particularly stereotactic radiosurgery (SRS) - are the primary treatment options. SRS is the dominant treatment for small- and medium-sized VS and selected larger tumors due to its excellent local control rates and favorable safety profile compared to surgery. However, careful treatment planning is essential, taking into account patient preferences, tumor location and size, symptoms, and anticipated treatment-related toxicity.

Methods and materials: Four clinical VS scenarios have been selected to illustrate the use of SRS, including a unilateral, small intracanalicular VS, a large VS with cystic components, reirradiation with SRS after local tumor recurrence, and bilateral VS in the setting of neurofibromatosis type 2-related schwannomatosis.

Results: SRS is an effective and safe treatment modality for the majority of VS cases, requiring careful treatment planning and a thorough understanding of potential limitations and challenges.

Conclusions: This case-based practice guide aims to provide a concise overview of the treatment of VS with SRS. We present and discuss four different clinical scenarios of VS to illustrate the pitfalls and best practice recommendations.

Purpose: Partial breast irradiation (PBI) delivered with intensity modulated radiation therapy over 5 fractions every other day represents an attractive, convenient method of delivering adjuvant radiation therapy for well-selected patients without compromising oncologic or toxicity outcomes. Condensing this regimen to a week of treatment through consecutive daily delivery may further increase patient convenience, though a comparison of toxicities between daily and every other day regimens is limited.

Methods and materials: We retrospectively reviewed 507 patients from an institutional registry undergoing PBI for ductal carcinoma in situ (DCIS) or early-stage breast cancer (T1-2N0/x) from 2015 to 2022. All patients received 30 Gy in 5 fractions with intensity modulated radiation therapy. Acute (toxicity within 90 days of treatment) and chronic toxicity were recorded.

Results: Of the 507 patients, 351 were treated every other day, and 159 were treated daily. Median follow-up was longer in the every-other-day group (2.4 vs 1.9 years, P < .001). With regards to acute toxicity, there was slightly reduced grade 1 to 2 dermatitis with daily treatment (39% every other day vs 35% daily, P = .06), while rates of fatigue (18% every other day vs 20% daily, P = .09) were similar. Rates of chronic toxicities were comparable between the two approaches, with no differences in the rates of chronic hyperpigmentation (14% every other day vs 14% daily, P = .97), telangiectasias (1% every other day vs 1% daily, P = .92), mild fibrosis/induration (13% every other day vs 13% daily, P = .91), and lymphedema (0% every other day vs 1% daily, P = .31).

Conclusions: Overall, 5-fraction PBI delivered daily appears to be well tolerated with similar acute and chronic toxicity to every other day fractionation.

Lorlatinib is a central nervous system-penetrant third-generation tyrosine kinase inhibitor approved for the first-line management of metastatic non-small cell lung cancer with anaplastic lymphoma kinase rearrangement,¹ which accounts for 3% to 5% of non-small cell lung cancer cases.² The most commonly reported side effects include hyperlipidemia, edema, peripheral neuropathy, and central nervous system effects.² Whereas ocular side effects such as photopsia, blurred vision, vitreous floaters, and diplopia have been documented with another anaplastic lymphoma kinase-tyrosine kinase inhibitor, crizotinib, there are few reports of such effects with lorlatinib.³ Herein, we present a case of bilateral optic neuropathy, initially misdiagnosed as optic nerve metastases and treated with palliative radiation therapy.