Radiation Oncology最新文献

Background: Radiation-induced temporal lobe necrosis (TLN) impairs long-term survival of patients with nasopharyngeal carcinoma (NPC) after radiotherapy (RT). We aimed to develop an early scoring model that integrats quantitative MRI indicators and clinical factors to enhance TLN risk stratification.

Methods: Longitudinal MRI scans acquired pre-RT and within 6 months post-RT in 439 patients with NPC (67 necrotic vs. 811 normal temporal lobes) included three-dimensional T1-weighted imaging for gray matter macrostructures and diffusion tensor imaging for white matter microstructures. Clinical and combined models were built using Cox regression, and their performances were compared to evaluate the incremental value of quantitative MRI biomarkers. A composite structural MRI-based risk score (CSS) was constructed for the TLN risk stratification. The incidence of TLN was predicted using a logistic dose-response model.

Results: Combining quantitative MRI biomarkers with clinical factors, such as age, diabetes, and TL radiation dose, significantly improved predictive accuracy and increased the C-index to 0.888 (P = 0.018). CSS effectively identified individuals at high risk for TLN; those with high CSS had a significantly higher TLN risk than those with low CSS (hazard ratio (HR) [95% confidence interval (CI)] = 3.07 [1.77-5.33], P < 0.001). Individuals with high CSS required a lower 50% tolerance dose for 5-year TLN (72.0 Gy) than those with low CSS (75.2 Gy).

Conclusions: Our CSS quantitatively characterized the longitudinal structural alterations in the temporal lobes pre- and post-RT. Integrating CSS with clinical and dosimetric parameters enables accurate TLN risk stratification and informs personalized management for patients with NPC.

Clinical trial number: Not applicable.

Background and purpose: This study aims to develop a robust and user-friendly prediction model for radiation-induced hypothyroidism (RIHT) in nasopharyngeal carcinoma (NPC) patients.

Materials and methods: NPC patients treated with IMRT between Jan. 2019 and Dec. 2021 were randomly assigned to a training cohort (n = 328) and a validation cohort (n = 141) at a ratio of 7:3. A total of 33 clinical and dose-volume variables were collected. Significant variables (p < 0.05) were identified through univariate Cox analysis and further refined using a 101-combination machine learning (ML) framework to develop a robust predictive model. The model was subsequently simplified through multivariate Cox analysis and a nomogram. Finally, the performance of the model was evaluated using the C-index, calibration plots, and decision curve analysis.

Results: Using a 101-combination ML framework, we developed a predictive model for RIHT in NPC. The Coxboost + RSF method with 11 predictors achieved the best performance (C-index: 0.91 [training], 0.71 [validation]). A simplified five-variable model (pre-treatment TSH, TSH-to-thyroid-volume ratio, age, V45, V20) was created via multi-cox regression, with a C-index of 0.80 [training] and 0.71 [validation]. High-risk patients had significantly higher three-year RIHT incidences (72.3% vs. 18.6%, p < 0.0001) in the training cohort, and 67.9% versus 24.4% (p < 0.0001) in the validation cohort. The model showed strong calibration and confirmed clinical utility through decision curve analysis, supporting its use in personalized treatment planning.

Conclusion: We developed a ML framework to identify key predictive factors for RIHT, which was simplified into a five-variable model for clinical use, offering a robust tool for predicting RIHT risk in decision-making.

Background: Long-term data on the efficacy of robotic stereotactic body radiotherapy (SBRT) for localized prostate cancer (LPC) remain limited. This study aimed to evaluate the 10-year treatment outcomes of SBRT in LPC patients and identify key prognostic factors.

Methods: A total of 82 patients with LPC who underwent five-fraction SBRT (doses of 35-37.5 Gy) were included. The median follow-up duration was 11.0 years (range, 3.3-15.9 years). Clinical outcomes, including the biochemical failure-free survival (BCFFS), clinical failure-free survival (CFFS), and prostate-specific antigen (PSA) kinetics, were analyzed to evaluate the impact of various clinical and treatment factors on prognosis.

Results: The 10-year BCFFS and CFFS rates were 86.3% (95% confidence interval [CI], 78.6-94.8) and 86.7% (95% CI, 78.8-95.4), respectively. Nine cases of biochemical failure were observed, alongside local (n = 1), regional (n = 2), and distant (n = 5) metastases. The cancer-specific survival rate was 100%. The median PSA nadir was 0.09 ng/ml (range, 0.0-3.12 ng/ml) and the median interval to PSA nadir was 52.8 months (range, 0.4-170.2 months). There was a negative correlation between the time to the PSA nadir and the PSA nadir value (r = -0.233, p = 0.035). Daily SBRT was associated with improved BCFFS compared to every-other-day treatment (hazard ratio [HR], 0.220; 95% CI, 0.067-0.720; p = 0.012), while a longer interval to PSA nadir (≥ 5 years) was associated with better CFFS (HR, 0.120; 95% CI, 0.015-0.944; p = 0.044).

Conclusions: Robotic SBRT for LPC demonstrates durable long-term efficacy. Daily treatment schedules and interval to PSA nadir were identified as crucial prognostic indicators. These findings highlight the importance of PSA kinetics in predicting treatment success following robotic SBRT.

Background: This study evaluates the long-term anorectal function and rectal toxicity in rectal cancer patients who achieved a clinical complete response (cCR) to total neoadjuvant treatment (TNT) and were managed with a watch-and-wait (W&W) approach. While oncological outcomes have been favorable, functional outcomes warrant further investigation. Additionally, this research identifies clinical risk factors of anorectal dysfunction post-treatment.

Methods: This was a single-center, cross-sectional study. Rectal cancer patients who underwent TNT followed by W&W between December 2014 and November 2020 were recruited. A minimum 2-year follow-up with no disease progression was required. The study took the form of semi-structured interviews. Multiple scales for evaluation were used, including the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer (RTOG/EORTC) scale, the Late Effects of Normal Tissues/Subjective Objective Management Analytic (LENT/SOMA) system, the Wexner score, the Low Anterior Resection Syndrome (LARS) score and the Memorial Sloan Kettering Cancer Center Bowel Function Instrument (MSKCC BFI). Univariate analysis and multi-factor Logistic regression were used to identify the risk factors for anorectal dysfunction.

Results: Out of 70 patients with a median follow-up of 43 months, less than half experienced grade I (28/70, 40.0%) or II (1/70, 1.4%) late rectal toxicity according to the RTOG/EORTC criteria, with no cases of more severe toxicity. The prevalence of fecal urgency was the most significant symptom reported (42/70, 60.0%). The median LARS score was 16 [interquartile ranges (IQR) 4-25]; 17.1% (12/70) of patients had minor LARS and 15.7% (11/70) had major LARS. The median Wexner score was 2 (IQR 0-3). The median MSKCC BFI total score was 82.5 (IQR 77-86). Smoking history was an independent risk factor for long-term anorectal dysfunction [odds ratio (OR) 6.562, 95% confidence interval (CI) 1.561-27.590].

Conclusion: Most rectal cancer patients under a W&W strategy after TNT sustain acceptable anorectal function, though fecal urgency remains a common issue. Smoking history emerged as a significant risk factor for anorectal dysfunction. Larger prospective studies focusing on bowel function are needed.

Extramedullary hematopoiesis (EMH) is a compensatory response to chronic anemia, commonly observed in thalassemia. EMH can cause neurological complications such as spinal cord compression and paraparesis, as well as other site-specific compressive symptoms necessitating timely intervention. While medical management and surgery have been explored, radiation therapy (RT) remains a safe and effective alternative. This case series presents five patients with thalassemia who developed symptomatic EMH. All patients exhibited compressive symptoms, including lower limb weakness, sensory deficits, and abdominal pain. They were treated with conformal external beam RT using volumetric modulated arc therapy (VMAT) at doses ranging from 20 to 24 Gy in 10-12 fractions. Symptomatic relief was achieved within days of initiating radiation treatment, with near-complete neurological recovery by treatment completion. MRI follow-ups over 1-2 years demonstrated significant regression of EMH masses, and there was no recurrence of symptoms. Radiation was well tolerated and no treatment-related toxicities were observed. This study highlights the role of radiation treatment as a non-invasive and effective treatment modality for symptomatic EMH. The rapid clinical response and durable control observed in these cases reinforce its potential as a primary intervention, particularly in patients who are not responding and progressing on medical management. A dose range of 20-24 Gy in 10-12 fractions by modern radiation delivery techniques is recommended for the management of extramedullary hematopoietic masses.

Background: Bone metastases cause significant pain and functional limitation. Conventional external beam radiotherapy (EBRT) provides effective symptom relief, but local progression remains frequent. Stereotactic body radiotherapy (SBRT) offers improved local control but is often resource-intensive and associated with higher vertebral compression fracture (VCF) rates. Integrating a simultaneous gross tumour volume (GTV) boost within a conventional EBRT regimen may provide a feasible and safe alternative.

Methods: This is a prospective, multicentre, multinational, single-arm study enrolling 100 adults with painful bone metastases from solid tumours. Eligible patients receive 20 Gy in 5 fractions with a 5 Gy "stereotactic-lite" GTV boost (total 25 Gy) or 30 Gy in 10 fractions with a 6 Gy boost (total 36 Gy), delivered using intensity modulated radiotherapy or volumetric modulated arc therapy. The primary endpoints are feasibility (commencement of radiotherapy within 10 working days of computed tomography simulation in at least 80% of patients) and safety (incidence of Common Terminology Criteria for Adverse Events version 5.0 grade ≥ 2 acute toxicity within 3 months). Secondary endpoints include pain response, radiation site-specific progression-free survival, rates of VCF and long bone fracture, skeletal-related events, quality of life changes via EORTC QLQ-C30 and BM22, and overall survival.

Discussion: This protocol evaluates a hybrid EBRT approach with a simultaneous integrated boost as a practical strategy to enhance local tumour control and symptom relief without delaying palliation. If feasible and safe, this approach may bridge the gap between conventional EBRT and SBRT.

Trial registration: Australian and New Zealand Clinical Trial Registry (ACTRN12625000615482).