4DCT ventilation function image-based functional lung protection for esophageal cancer radiotherapy.

BACKGROUND: 4DCT (four-dimensional computed tomography) can effectively obtain functional lung ventilation images for patients and integrate them into radiotherapy treatment planning. Studies have not been performed on esophageal cancer, and there is no clear consensus on the optimal functional lung threshold for functional lung. METHODS: Functional lung images were generated for 11 patients with esophageal cancer. The correlation between the dose-volume parameters of functional lung (FL) as defined by different thresholds and the change of PFT/PDFT (pulmonary [diffusion] function test) metrics before and after radiotherapy were evaluated. FL-sparing planning was generated for each patient to preserve the functional lung and compared to conventional anatomical CT (non-sparing) planning. RESULTS: There was a significant positive correlation between the FL0.8 (defined Jacobian value ≤ 0.8), FL0.84, and FL0.9 dose-volume parameters and ΔFEV1/FVC (reduction before and after radiotherapy), and the FL0.8­V30 correlation was the strongest (r = 0.819, P < 0.01). The FL-sparing planning had a target area conformity index and homogeneity index comparable to the non-sparing planning (P > 0.05). For FL, the FL-sparing planning achieved lower FL-MLD (6.30 ±â€¯2.14 Gy vs. 7.83 ± 2.70 Gy), V10 (17.13 ±â€¯7.70% vs. 27.40 ± 9.48%), and V20 (6.96 ±â€¯3.85% vs. 11.63 ± 7.19%) compared to the non-sparing planning (P < 0.05), while heart and spinal cord doses were not significantly different between the two planning groups. CONCLUSION: The 4DCT-based FL irradiation dose for esophageal cancer was significantly associated with a decrease in FEV1/FVC. The optimal FL defined as a Jacobian value ≤ 0.8 or about 21% of the whole lung volume may be a good choice. FL-sparing planning significantly reduced the FL dose without compromising target area coverage.

Clinical outcomes of pelvic bone marrow sparing radiotherapy for cervical cancer: A systematic review and meta-analysis of randomised controlled trials.

Background: Concurrent chemoradiotherapy (CRT) is the standard treatment for locally advanced cervical cancer. We investigated how additional bone marrow sparing (BMS) affects the clinical outcomes. Methods: We queried MEDLINE, Embase, Web of Science Core Collection, Google Scholar, Sinomed, CNKI, and Wanfang databases for articles published in English or Chinese between 2010/01/01 and 2023/10/31. Full-text manuscripts of prospective, randomised trials on BMS in cervical cancer patients treated with definitive or postoperative CRT were included. Risk of bias (RoB) was assessed using Cochrane Collaboration's RoB tool. Random-effects models were used for the meta-analysis. Results: A total of 17 trials encompassing 1297 patients were included. The majority were single-centre trials (n = 1268) performed in China (n = 1128). Most trials used CT-based anatomical BMS (n = 1076). There was a comparable representation of trials in the definitive (n = 655) and postoperative (n = 582) settings, and the remaining trials included both.Twelve studies reported data on G ≥ 3 (n = 782) and G ≥ 2 (n = 754) haematologic adverse events. Both G ≥ 3 (OR 0.39; 95 % CI 0.28-0.55; p < 0.001) and G ≥ 2 (OR 0.29; 95 % CI 0.18-0.46; p < 0.001) toxicity were significantly lowered, favouring BMS. Seven studies (n = 635) reported data on chemotherapy interruptions, defined as receiving less than five cycles of cisplatin, which were significantly less frequent in patients treated with BMS (OR 0.44; 95 % CI 0.24-0.81; p = 0.016). There was no evidence of increased gastrointestinal or genitourinary toxicity.There were no signs of significant heterogeneity. Four studies were assessed as high RoB; sensitivity analyses excluding these provided comparable results for main outcomes. The main limitations include heterogeneity in BMS methodology between studies, low representation of populations most affected by cervical cancer, and insufficient data to assess survival outcomes. Conclusions: The addition of BMS to definitive CRT in cervical cancer patients decreases hematologic toxicity and the frequency of interruptions in concurrent chemotherapy. However, data are insufficient to verify the impact on survival and disease control.

Efficacy and Safety in Proton Therapy and Photon Therapy for Patients With Esophageal Cancer: A Meta-Analysis.

Importance: Radiotherapy plays an important role in the treatment of esophageal cancer. Proton therapy has unique physical properties and higher relative biological effectiveness. However, whether proton therapy has greater benefit than photon therapy is still unclear. Objective: To evaluate whether proton was associated with better efficacy and safety outcomes, including dosimetric, prognosis, and toxic effects outcomes, compared with photon therapy and to evaluate the efficacy and safety of proton therapy singly. Data Sources: A systematic search of PubMed, Embase, the Cochrane Library, Web of Science, SinoMed, and China National Knowledge Infrastructure databases was conducted for articles published through November 25, 2021, and updated to March 25, 2023. Study Selection: For the comparison of proton and photon therapy, studies including dosimetric, prognosis, and associated toxic effects outcomes were included. The separate evaluation of proton therapy evaluated the same metrics. Data Extraction and Synthesis: Data on study design, individual characteristics, and outcomes were extracted. If I2 was greater than 50%, the random-effects model was selected. This meta-analysis is reported following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline. Main Outcomes and Measures: The main outcomes were organs at risk (OARs) dosimetric outcomes, prognosis (overall survival [OS], progression-free survival [PFS], and objective response rate [ORR]), and radiation-related toxic effects. Results: A total of 45 studies were included in the meta-analysis. For dosimetric analysis, proton therapy was associated with significantly reduced OARs dose. Meta-analysis showed that photon therapy was associated with poor OS (hazard ratio [HR], 1.31; 95% CI, 1.07-1.61; I2 = 11%), but no difference in PFS was observed. Subgroup analysis showed worse OS (HR, 1.42; 95% CI, 1.14-1.78; I2 = 34%) and PFS (HR, 1.48; 95% CI, 1.06-2.08; I2 = 7%) in the radical therapy group with photon therapy. The pathological complete response rate was similar between groups. Proton therapy was associated with significantly decreased grade 2 or higher radiation pneumonitis and pericardial effusion, and grade 4 or higher lymphocytopenia. Single-rate analysis of proton therapy found 89% OS and 65% PFS at 1 year, 71% OS and 56% PFS at 2 years, 63% OS and 48% PFS at 3 years, and 56% OS and 42% PFS at 5 years. The incidence of grade 2 or higher radiation esophagitis was 50%, grade 2 or higher radiation pneumonitis was 2%, grade 2 or higher pleural effusion was 4%, grade 2 or higher pericardial effusion was 3%, grade 3 or higher radiation esophagitis was 8%, and grade 4 or higher lymphocytopenia was 17%. Conclusions and Relevance: In this meta-analysis, proton therapy was associated with reduced OARs doses and toxic effects and improved prognosis compared with photon therapy for esophageal cancer, but caution is warranted. In the future, these findings should be further validated in randomized clinical trials.

Functional lung imaging in thoracic tumor radiotherapy: Application and progress.

Radiotherapy plays an irreplaceable and unique role in treating thoracic tumors, but the occurrence of radiation-induced lung injury has limited the increase in tumor target doses and has influenced patients' quality of life. However, the introduction of functional lung imaging has been incorporating functional lungs into radiotherapy planning. The design of the functional lung protection plan, while meeting the target dose requirements and dose limitations of the organs at risk (OARs), minimizes the radiation dose to the functional lung, thus reducing the occurrence of radiation-induced lung injury. In this manuscript, we mainly reviewed the lung ventilation or/and perfusion functional imaging modalities, application, and progress, as well as the results based on the functional lung protection planning in thoracic tumors. In addition, we also discussed the problems that should be explored and further studied in the practical application based on functional lung radiotherapy planning.

Functional Liver Imaging in Radiotherapy for Liver Cancer: A Systematic Review and Meta-Analysis.

Backgrounds: Functional liver imaging can identify functional liver distribution heterogeneity and integrate it into radiotherapy planning. The feasibility and clinical benefit of functional liver-sparing radiotherapy planning are currently unknown. Methods: A comprehensive search of several primary databases was performed to identify studies that met the inclusion criteria. The primary objective of this study was to evaluate the dosimetric and clinical benefits of functional liver-sparing planning radiotherapy. Secondary objectives were to assess the ability of functional imaging to predict the risk of radiation-induced liver toxicity (RILT), and the dose-response relationship after radiotherapy. Results: A total of 20 publications were enrolled in descriptive tables and meta-analysis. The meta-analysis found that mean functional liver dose (f-MLD) was reduced by 1.0 Gy [95%CI: (-0.13, 2.13)], standard mean differences (SMD) of functional liver volume receiving ≥20 Gy (fV20) decreased by 0.25 [95%CI: (-0.14, 0.65)] when planning was optimized to sparing functional liver (P >0.05). Seven clinical prospective studies reported functional liver-sparing planning-guided radiotherapy leads to a low incidence of RILD, and the single rate meta-analysis showed that the RILD (defined as CTP score increase ≥2) incidence was 0.04 [95%CI: (0.00, 0.11), P <0.05]. Four studies showed that functional liver imaging had a higher value to predict RILT than conventional anatomical CT. Four studies established dose-response relationships in functional liver imaging after radiotherapy. Conclusion: Although functional imaging modalities and definitions are heterogeneous between studies, but incorporation into radiotherapy procedures for liver cancer patients may provide clinical benefits. Further validation in randomized clinical trials will be required in the future.

Different functional lung-sparing strategies and radiotherapy techniques for patients with esophageal cancer.

Background: Integration of 4D-CT ventilation function images into esophageal cancer radiation treatment planning aimed to assess dosimetric differences between different functional lung (FL) protection strategies and radiotherapy techniques. Methods: A total of 15 patients with esophageal cancer who had 4D-CT scans were included. Lung ventilation function images based on Jacobian values were obtained by deformation image registration and ventilation imaging algorithm. Several different plans were designed for each patient: clinical treatment planning (non-sparing planning), the same beam distribution to FL-sparing planning, three fixed-beams FL-sparing intensity-modulated radiation therapy (IMRT) planning (5F-IMRT, 7F-IMRT, 9F-IMRT), and two FL-sparing volumetric modulated arc therapy (VMAT) planning [1F-VMAT (1-Arc), 2F-VMAT (2-Arc)]. The dosimetric parameters of the planning target volume (PTV) and organs at risk (OARs) were compared and focused on dosimetric differences in FL. Results: The FL-sparing planning compared with the non-sparing planning significantly decreased the FL-Dmean, V5-30 and Lungs-Dmean, V10-30 (Vx: volume of receiving ≥X Gy), although it slightly compromised PTV conformability and increased Heart-V40 (P< 0.05). The 5F-IMRT had the lowest PTV-conformability index (CI) but had a lower Lungs and Heart irradiation dose compared with those of the 7F-IMRT and 9F-IMRT (P< 0.05). The 2F-VMAT had higher PTV-homogeneity index (HI) and reduced irradiation dose to FL, Lungs, and Heart compared to those of the 1F-VMAT planning (P< 0.05). The 2F-VMAT had higher PTV conformability and homogeneity and decreased FL-Dmean, V5-20 and Lungs-Dmean, V5-10 but correspondingly increased spinal cord-Dmean compared with those of the 5F-IMRT planning (P< 0.05). Conclusion: In this study, 4D-CT ventilation function image-based FL-sparing planning for esophageal cancer can effectively reduce the dose of the FL. The 2F-VMAT planning is better than the 5F-IMRT planning in reducing the dose of FL.

Pelvic bone marrow sparing radiotherapy for cervical cancer: A systematic review and meta-analysis.

BACKGROUNDS: Concurrent chemo-radiotherapy in patients with locally advanced cervical cancer has significant hematologic toxicities (HT), leading to treatment disruption and affecting patient prognosis. We performed the meta-analysis to assess the clinical benefit of pelvic (active) bone marrow (BM) sparing radiotherapy. METHODS: A systematic methodological search of six primary electronic databases was performed. This systematic review mainly assessed the differences in pelvic (active) BM dose-volume parameters (DVP), hematologic toxicity of pelvic (active) BM sparing versus non-sparing radiotherapy plans. The secondary objective was to explore optimal dose limitation regimens and evaluate other radiation-induced toxicities (gastrointestinal and urological toxicity (GT/UT)). Random-effects models were used for meta-analysis. RESULTS: Final 65 publications that met inclusion criteria were included in the meta-analysis and descriptive tables. Meta-analysis of mean pelvic BM-DVP differences showed that pelvic BM-V10,20,40,50 (Vx: volume of BM receiving ≥ X Gy) were reduced by -4.6% [95% CI: -6.6, -2.6], -10.9% [-13.2, -8.6], -7.3% [-9.5, -5.2] and -3.4% [-4.3, -2.4] in pelvic BM-sparing plans. Pelvic BM sparing radiotherapy decreased G2/3+ HT [odds ratio (OR) 0.31, (0.23, 0.41)/0.42, (0.28, 0.63)], without increasing GT [G2/3+: OR 0.76, (0.51, 1.14)/0.90, (0.47, 1.74)] and UT [G2/3+: OR 0.91, (0.57, 1.46)/0.54, (0.25, 1.17)]. Pelvic active BM sparing radiotherapy also reduced HT [G2/3+ HT: OR 0.42, (0.23, 0.77)/0.34, (0.16, 0.72)]. There were significant variations between publications in dose restriction regimens. CONCLUSION: The pelvic BM protection radiotherapy can decrease BM dose and HT. Moreover, it does not increase GT and UT. The clinical benefit of pelvic active BM protection needs to be further validated in randomized controlled trials.