International Journal of Radiation Oncology Biology Physics最新文献

Purpose: Primary Hepatocellular Carcinoma (HCC) lesions are frequently treated with fractionated radiation therapy. The linear-quadratic (LQ) model can be used to compare different fractionation schemes for their effect on the local recurrence rate of the HCC tumors. In this paper we seek to find the value of the α/β ratio in the LQ model, which gives the best prediction of the recurrence rate.

Methods and materials: Two separate datasets were analyzed. The first dataset contains the time to recurrence of 390 lesions, treated at two institutions between 2008 and 2021. Factors considered were the Gross Tumor Volume (GTV), the fractionation scheme, the Dose-Volume-Histogram (DVH) of GTV and the elapsed time between the first and last dose of radiation. Four different ways of summarizing the DVH, based on the LQ model, were used and combined with the Cox proportional hazards model to estimate the α/β ratio. The second dataset contains the recurrence rate at 1, 2, 3, 4 and 5 years, for 46 different fractionation schemes, derived from the results presented in 41 publications, based on a total of 4,313 lesions. For this meta-analysis a linear model of a transformed recurrence rate, assuming an autoregressive covariance structure, was used to estimate the α/β ratio.

Results: From the lesion level data the best estimate of α/β was in the range 37.5 to 52 Gy, with a wide confidence interval of (3.4, ∞). A combined model of how the radiation was delivered, based on the fraction regimen and elapsed time, was strongly associated with the hazard of recurrence (p<0.001). However, the elapsed time alone was not significantly associated with the hazard of recurrence (hazard ratio for a 1 day increase = 1.01, p=0.33). The analysis also suggested that larger GTV may lead to a higher hazard of recurrence, but was not statistically significant (hazard ratio of log(GTV)=1.12, p=0.21). Lower doses in the DVH were better predictors of the outcome than the mean DVH dose. The meta analysis of the published data gave the best estimate of α/β ratio of 161.4Gy, but with a wide confidence interval (4.7,∞).

Conclusions: Both analyses suggested a high value of α/β of at least 37.5Gy, but neither could provide precise estimates and only very small values could be excluded. From a practical perspective, any value of the α/β ratio of greater than about 20Gy would give a similar ranking of the merits of different fractionation schemes. To obtain more precise estimates of α/β, the datasets would need to include more patients who received fractionated radiation with doses per fraction in the range of 2.0 to 2.9Gy.

Purpose: Improved communication by clinicians at initial consultation may reduce anxiety and psychological burden of cancer treatment. Based on our pilot qualitative study which involved semi-structured interviews with breast cancer patients, we developed Curietherapy User eXperience (CurieUx), an educational tool integrating augmented reality display technology into radiation oncology consultations.

Methods: We developed an interactive 3-dimensional hologram using an augmented reality desktop display. Animated modules on patient-specific anatomy (breast, regional lymph nodes, organs-at-risk), simulation, linear accelerator, and positioning (prone and breath holding techniques) were created. Patients with newly diagnosed breast cancer undergoing initial radiation oncology consult were prospectively enrolled. Likert scale surveys on anxiety (NIH PROMIS), radiation knowledge, and augmented reality experience (modified IBM technology usability survey) were administered to patients before and after consultation.

Results: A total of 40 newly diagnosed breast cancer patients were enrolled in this proof-of-concept study at a median age of 67 years. Patients reported decreases in multiple components of anxiety after consultation with the CurieUx platform, including in fearfulness (2.13 vs 1.78, p=0.003), uneasiness (2.28 vs. 1.82, p=0.008), nervousness (2.41 vs 2.06, p=0.005), and tenseness (2.28 vs 1.87, p=0.004). Patients reported significant increases in radiation knowledge across multiple domains, including treatment machine (2.35 vs 4.7, p<0.001), radiation (2.7 vs 4.58, p<0.001), positioning (2.49 vs 4.68, P<0.001), and confidence (2.4 vs 4.3, p<0.001). An overwhelming majority of patients had positive experiences (4 or 5 on Likert scale) using the CurieUx hologram display as part of consultation, including its ease of understanding (97%), clarity (93%), comfort (100%), value (97%), and satisfaction (97%).

Conclusion: Curietherapy User eXperience is a valuable educational tool that reduces patient anxiety and promotes radiation knowledge. In this feasibility study, the vast majority of patients found the incorporation of CurieUx into the existing radiation oncology consultation practice to be a valuable addition to the process.

Purpose: Randomized evidence suggests tumor bed boost improves local control following whole breast radiotherapy (WBRT) but may lead to more acute and late toxicity. However, little data is available about toxicity in real world practice from a tumor bed boost delivered after WBRT, particularly following moderate dose hypofractionation (MH). We evaluated acute toxicity and cosmesis effects associated with use of a boost after MH-WBRT in a large prospective cohort.

Methods and materials: This analysis includes women undergoing adjuvant MH-WBRT without regional nodal irradiation, prospectively enrolled from January 2012 to November 2023 at 30 radiation oncology centers in a statewide quality consortium. Standardized patient, physician, and physicist forms were used to collect baseline and follow-up information. A severe toxicity composite variable included patient- or physician-reported breast pain or moist desquamation. Cosmesis scores were evaluated at 1 year. Multivariable models were used to find associations between boost and toxicity outcomes.

Results: Clinical and treatment data were available for 11,753 women. A photon or electron boost was used in 49.0% and 22.1% of patients, respectively; 28.9% received no boost. The mean MH-WBRT dose to 95% of the volume was 40.6Gy; median boost dose was 10Gy/4 fractions. Both boost types were associated with greater composite acute toxicity, patient-reported breast pain, physician-reported breast pain, and grade 2+ dermatitis, p<0.001. Fair/poor cosmesis was not associated with electron boost, though an association with photon boost cannot be excluded (OR 1.30, 95% CI 1.00 - 1.68).

Conclusions: Using real world data, an electron or photon boost following MH-WBRT is associated with significantly more acute breast pain and dermatitis. While there was no deleterious effect of an electron boost on cosmesis at 1 year, the impact of a photon boost is unclear. These data may help shared decision making when discussing the benefits and risks of a boost following MH-WBRT.

Stereotactic ablative radiotherapy (SABR), or stereotactic body radiotherapy (SBRT), has emerged as a new standard of care treatment option for localized renal cell carcinoma {RCC). Here we present an accessible, high-yield guide to implementing SABR for RCC. A Q&A format was selected for ease of navigation. Common queries around treatment indications and patient selection to SABR planning, delivery, and follow-up are addressed. Succinct, quick-hit answers are supported by relevant, contemporary literature.

Purpose: The expanded HILUS study showed that bronchial dose and bronchial tumor compression are risk factors for bronchopulmonary bleedings after stereotactic body radiation therapy of centrally located lung tumors. In the current analysis of the same cohort, the aim was to identify the dose-volume histogram (DVH) parameter that best predicts fatal bronchopulmonary bleeding and to develop a predictive model for this endpoint.

Methods and materials: The HILUS cohort included 230 patients with 238 central targets treated with stereotactic body radiation therapy of 7 Gy × 8 to the periphery of the planning target volume, where 21 patients developed grade-5 bronchopulmonary bleeding. Cox regression-based normal-tissue complication probability models were developed, accounting for the dose to the main and intermediate bronchi and bronchial tumor compression. Three alternative DVH parameters were explored: the dose to a certain volume (D_v), the volume receiving a certain dose (V_d), and the equivalent uniform dose. Internal validation was performed with the bootstrap method.

Results: The best fits of the bivariable normal-tissue complication probability models included bronchial tumor compression in combination with the DVH parameters of D_{0.31 cm3}, V_{82Gy,EQD2 (equivalent dose in 2-Gy fractions)}, and equivalent uniform dose with n = 0.024, respectively. This indicates that a high dose to a small volume may lead to grade-5 bronchopulmonary bleeding. The probability of fatal bleeding at 2 years without bronchial tumor compression was 10% for a D_{0.31 cm3} of 107 Gy₃ EQD₂, and 20% at 165 Gy₃ EQD₂, whereas the probability with bronchial tumor compression was 10% at 0 Gy₃ and 20% at 58 Gy₃ EQD₂. The model showed good discrimination and calibration.

Conclusions: Bronchial tumor compression is a strong predictor for grade-5 bleeding, and the most relevant dose parameter appears to be the dose to a small volume of the main and intermediate bronchi.

Purpose: Stereotactic body radiotherapy (SBRT) with focal boost to the dominant intraprostatic lesion (DIL) provides a strategy to enhance outcomes in high-risk localised prostate cancer while minimising toxicity. This study assessed late toxicity and quality of life (QOL) following CyberKnife-based SBRT with a simultaneous integrated boost in localised prostate cancer.

Methods and material: Patients with newly diagnosed, biopsy-proven unfavourable intermediate- to high-risk localised prostate cancer (at least one of the following: Gleason ≥ 4+3, MRI-defined T3a N0, PSA ≥ 20) with up to two MRI-defined DILs were enrolled. Participants received 36.25 Gy in 5 fractions with a simultaneous focal boost up to 47.5 Gy delivered using CyberKnife. All participants received androgen deprivation therapy. The current analysis reports RTOG-assessed late genitourinary (GU) and gastrointestinal (GI) toxicity, late IPSS and urinary QOL, late IIEF-5 assessed sexual function, late EQ5D-5L QOL and biochemical outcomes at 2 years.

Results: Between 2013 and 2023, 20 participants were enrolled with a median follow-up of 54 months (IQR, 24-108months). The median D95 dose delivered to the DIL was 47.43Gy. At 2 years, the cumulative rate of RTOG-assessed grade 2 or greater GU and GI toxicity was 35% (95% confidence interval [CI]: 15% - 59%) and 5% (95% CI: 1% - 25%) respectively. The prevalence of grade 2 GU and GI toxicity at 2 years was 0% and there was no late grade 3 GU and GI toxicity. There was no clinically significant worsening of EQ5D-5L-assessed QOL, IPSS score and urinary QOL scores at 2 years compared to baseline. There was a reduction in IIEF-5 scores for sexual function at 2 years (median 10, IQR 5-18) from baseline (median 18, IQR 6-22). There is one case of biochemical relapse reported to date.

Conclusions: CyberKnife-based SBRT delivering 36.25 Gy to the prostate with a simultaneous integrated boost up to 47.5 Gy is well tolerated at 2 years. The cumulative rates of grade ≥ 2 GU and GI toxicity were 35% and 5% respectively, consistent with other contemporary SBRT trials with and without focal boost.

Purpose/objectives: Metachronous oligometastases may represent a favorable disease state for local therapy after prior curative treatment. Stereotactic Magnetic Resonance Guided Adaptive Radiation Therapy (SMART) provides precise targeting of nodal and soft tissue metastases. The primary objective was to assess the feasibility and safety of SMART for abdominopelvic metachronous oligometastases. Secondary objectives included assessing rates of toxicities and evaluating local control (LC).

Materials/methods: Ten patients were enrolled with solid-tumor metachronous abdominopelvic nodal or soft tissue metastases, ≤ 7cm in maximal diameter, and ≤ 3 sites of active disease. All patients received 40 Gy in 5 fractions. Acute toxicities were graded per CTCAEv5 per-protocol follow-up over one year. Late toxicities and clinical outcomes were elucidated by chart review. LC, distant progression-free survival (dPFS), and overall survival (OS) were analyzed using the Kaplan-Meier Method.

Results: Eight patients with prostate cancer (PCa) and two with renal cell carcinoma (RCC) were enrolled in the study. All patients were successfully treated with SMART per-protocol without complications. The median follow-up after SMART was 4.22 years. Three patients experienced acute grade 1 toxicities; there were no higher grade or late toxicities. Among these ten patients, four-year LC and OS were both 90%, and 4-year dPFS was 20%. Two patients (one PCa, one RCC) remain with no evidence of disease (NED), each at over four years following SMART and without receiving further systemic or local therapies.

Conclusions: With four years median follow-up, this small prospective trial reports low toxicity, supporting the feasibility of SMART metastasis-directed therapy for metachronous oligometastases with minimal risk of acute or late toxicity.