Practical Radiation Oncology最新文献

Purpose: Locally advanced endometrial cancers are heterogeneous and challenging to treat. Immunotherapy has transformed the treatment landscape. Given the complexity of tailoring adjuvant treatment recommendations, the multidisciplinary American Radium Society (ARS) Gynecologic Cancer Panel created evidence-based guidelines for management of locally advanced endometrial adenocarcinoma.

Methods and materials: Search terms, key questions, and associated clinical case variants were formed by panel consensus. A review of the literature was conducted from January 1, 1996 to March 5, 2024, using the Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA) guidelines to systematically search the PubMed, Embase, and Web of Science databases to retrieve a comprehensive set of relevant articles. A well-established methodology (modified Delphi) was used by the expert panel to rate the appropriate use of procedures.

Results: Evidence for key questions in advanced staged endometrial cancer was examined. Two rounds of voting were completed pertaining to the appropriateness of key management decisions for 4 clinical variants. Optimal adjuvant treatment is based on pathologic and molecular risk factors, and typically consists of combined modality therapy, with both chemotherapy and radiation, to minimize risk of local and distant recurrence; there are no prospective data on optimal sequencing. Molecular data from PORTEC-3 highlights that adding chemotherapy to radiation is especially crucial for p53 abnormal tumors. Inclusion criteria for the NRG-GY018/RUBY trials can guide appropriateness of incorporating immunotherapy, which should be considered especially in mismatch repair deficient (dMMR) patients. Radiation fields should be extended to include para-aortic lymph nodes in IIIC2 disease. Within pelvic radiation, intensity modulated radiotherapy is the preferred technique to mitigate toxicity as supported by prospective data.

Conclusion: Selecting appropriate adjuvant therapies for advanced stage endometrial cancer is nuanced. Further prospective studies harnessing molecular markers as therapeutic targets will help advance and optimize therapies for more personalized treatment of this complex disease.

Background: Modesty affects patient experience of healthcare and health outcomes. Radiotherapy often requires body exposure. Little is known about modesty and patient unease during radiotherapy across diverse populations and treatment sites. This study examined current practice and patient perceptions regarding modesty and associated unease during radiotherapy to the thorax and pelvis areas.

Methods: A 38-question survey was distributed to patients undergoing thoracic or pelvic radiotherapy across four centres. Item response theory (IRT) analysed the psychometric properties of unease. A structural equation model identified factors associated with unease. Summative content analysis of free text responses was conducted.

Results: 312 participants responded: 76% were female, 69% received thoracic radiotherapy, 43% were foreign-born, and 65% spoke a language other than English. 10% of participants indicated they were never informed about the need to undress, 26% received written information regarding the need to undress. This survey was reliable for patients with average or above levels of unease (IRT theta values > -0.3). 67.5% of variance of unease in the treatment room was explained by unease in the waiting room, gender of treating staff and baseline levels of modesty unease (p < 0.001). Staff kindness and professionalism were connected to patient ease in the treatment room. Functionality of treatment garments and waiting spaces were also themes connected to patient ease (f=41% and 46% respectively).

Conclusion: Patient modesty can affect unease in radiotherapy waiting and treatment rooms. This is the first study to demonstrate this in both a multicultural population, and across different anatomical treatment sites. Simply worded questionnaires can distinguish responders with higher than average unease. Personalisable treatment garment and waiting space options are recommended. Patient education materials can be improved by clearly outlining the requirement of patients to undress during treatment delivery.

Purpose: Deep inspiration breath-holding (DIBH) technique for left breast cancer reduces cardiac radiation exposure but requires additional DIBH-CT scans to confirm patient suitability, increasing radiation dose and costs. We propose an innovative screening approach using high-performance DIBH-CT synthesis and quantitative dose prediction.

Methods and materials: A two-stage model was first developed: (1) A synthetic DIBH-CT (sDIBH-CT) was generated from free-breathing CT (FB-CT) via an attention U-Net. (2) The synthetic model was retrained using FB-CT and patient-specific DIBH orthogonal projections of test patients to obtain a refined sDIBH-CT. The FB-CT was then registered to the refined sDIBH-CT and the consequent deformation vector field was used to obtain the final predicted DIBH-CT (pDIBH-CT) and associated contours. A dose prediction model estimated the mean heart dose (MHD) for pDIBH-CT. Registration accuracy was quantified by the Dice similarity coefficient (DSC), while image quality was assessed using the mean absolute error (MAE). Furthermore, MHD reduction thresholds were established to stratify DIBH-suitable patients: patients with FB-MHD >4 Gy required ≥30% MHD reduction with DIBH, while those with FB-MHD ≤4 Gy required ≥50% reduction. The retrospective study was evaluated using 178 patients treated with left-sided breast radiotherapy.

Results: The MAE between FB-CT and DIBH-CT decreased from 178.49 ± 41.95 HU to 55.19 ± 14.10 HU after generating pDIBH-CT. The DSC increased from 0.50 ± 0.19 to 0.87 ± 0.05 for CTV, 0.59 ± 0.17 to 0.89 ± 0.04 for PTV, 0.79 ± 0.05 to 0.92 ± 0.01 for the heart, and 0.81 ± 0.04 to 0.96 ± 0.01 for the lungs. The accuracy of the radiotherapy strategy screening reached 86.7% (13/15), with the predicted outcomes closely matching the actual DIBH treatment results.

Conclusions: We propose a rapid screening strategy for assessing DIBH suitability for patients treated with left-sided breast radiotherapy. This strategy has the potential to greatly optimize clinical workflow and reduce the burden on both patients and healthcare providers.

Purpose: Axillary substructures may contribute to the development of breast cancer-related lymphedema (BCRL). This study aimed to compare dose-volume parameters of various substructures to identify high-risk regions associated with BCRL and to evaluate the clinical applicability of these findings.

Methods and materials: Cohort-Initial included 336 patients with pT1-3N0-1M0 breast cancer who underwent mastectomy or lumpectomy with axillary lymph node dissection (ALND) and regional nodal irradiation (RNI) between August 2018 and February 2021. The Norman questionnaire was used to assess BCRL. Thirteen dose-volume parameters across 8 axillary substructures were assessed for association with BCRL. Cohort-Recurrence comprised 50 consecutive ALND-treated patients with regional nodal recurrence diagnosed using positron emission tomography/computed tomography, used to evaluate the recurrence risk in the candidate substructures. Cohort-Reoptimization involved 20 patients from the Cohort-Initial who received excessive radiation doses in the candidate substructure. Their treatment plans were reoptimized to assess the feasibility of dose reduction while maintaining target coverage and organ dose.

Results: The patient-reported cumulative incidence of BCRL was 33.9% during a median follow-up of 60 months. Significant baseline risk factors included body mass index ≥ 27.18 kg/m², tumor size ≥ 1.9 cm, premenopausal status, and ≥ 18 lymph nodes removed (all P < .05). The most significant dosimetric parameter was axillary-lateral thoracic vessel juncture (ALTJ)-V35_Gy ≥ 79.2%. A predictive nomogram incorporating these clinicopathologic factors and the ALTJ parameter was developed with reasonable accuracy, as confirmed by self-training (area under the curve value, 0.780) and internal validation (area under the curve value, 0.769). None of the 196 fluorodeoxyglucose-avid regional nodes in Cohort-Recurrence were located within the ALTJ. Reoptimization of ALTJ-V35_Gy was feasible without compromising the radiation therapy plan quality.

Conclusions: ALTJ-V35_Gy < 79.2% may serve as a recommended dose constraint for patients undergoing RNI after ALND. Avoiding excessive radiation to the ALTJ is clinically feasible and safe, potentially mitigating BCRL risk without compromising dose coverage to high-risk nodal regions.

Introduction: Current electron field shaping methods, such as milled copper cutouts and Cerrobend plates, are limited by toxic materials, recurring costs, and long turnaround times. To circumvent these issues, we designed a 3D-printed electron multi-leaf collimator (eMLC) that employs tungsten-infused polyethylene terephthalate glycol (W-PETG), a filament developed specifically for radiotherapy, to create the leaves. This study describes the feasibility assessment of this device to shape electron fields.

Methods: We first characterized the attenuation properties of W-PETG using stacks of variable thickness blocks (0.1-1 cm, flat 10 × 10 cm²) placed in a solid water phantom with a parallel plate chamber. Attenuation of 6 and 15 MeV electron beam energies were tested using various plate thicknesses. A prototype eMLC was designed to mount within a standard Elekta 14 × 14 cm² cone. The carriage was printed using generic PETG; interlocking leaves were printed using W-PETG. Interleaf and leaf-end leakage were evaluated using 1000 monitor units (MU) delivered through closed leaves. A clinical Cerrobend field was re-created with the eMLC, and both were compared using radiochromic film exposed to 200 MU using 6 and 15 MeV electron beams.

Results: W-PETG blocks of 1 cm thickness reduced 6 and 15 MeV electron beams to below 5% transmission. No measurable interleaf or end to end leaf leakage was detected at either energy using 1000 MU exposures. The eMLC resulted in a dose distribution nearly identical to Cerrobend. Compared to Cerrobend, the eMLC-generated fields demonstrated approximately 15% smaller penumbra and sharper field edges.

Conclusion: This novel 3D-printed eMLC using W-PETG provides dose-shaping characteristics comparable to conventional cutouts, with no detectable leakage and improved edge definition. Fabricated with consumer-grade equipment, this device provides reusable, customizable field shapes that may be suitable for clinical use. Further study of its validation and implementation into clinical workflows is warranted.

Real-time magnetic resonance (MR) guidance during brachytherapy (MRgBT) offers superior soft tissue definition and precise target identification during catheter implantation while minimizing treatment-related complications. This report reviewed the use of MRgBT in a series of complex clinical situations where brachytherapy would have been impossible without MR guidance, and alternate treatment modalities would have involved potentially significant morbidity to the patients. We highlighted the safety and efficacy of MRgBT in controlling targetable disease in a specific group of patients without precluding the ability to go for subsequent treatment options when indicated.

Purpose: To report the rapid recovery of treatment-related dysgeusia after tongue-out radiation therapy (TORT) for head and neck cancer (HNC).

Methods and materials: We retrospectively reviewed 14 patients with HNC who completed TORT with 70 Gy for definitive or salvage and 60 to 66 Gy for adjuvant treatment with or without concurrent chemotherapy. Patient-reported quality of taste was evaluated before, at the end of TORT therapy, and periodically 1, 3, and 6 months after TORT therapy using the University of Washington Quality of Life questionnaire version 4, question 9, including options for no-, mild-, and severe dysgeusia and ageusia. Oral cavity (OC) and oral tongue (OT) were contoured following guidelines. A portion of the anteriorly displaced OT outside the mouth was separately contoured as OT_OUT. Statistical analysis was conducted with the χ² and t test. A probability level of P < .05 was considered significant.

Results: In 14 TORT plans, the average volume of OC and OT was 105.8 ± 25.3 and 67.6 ± 20.7 cm³, respectively. OT_OUT comprised 20% (13.4 ± 9.1 cm³) of the entire OT volume. Average mean dose (D_MEAN) to OC, OT, and OT_OUT was 25.2 ± 6.9, 26.4 ± 6.8, and 13.3 ± 2.9 Gy, respectively. Before TORT, no-to-mild versus equal or higher than severe dysgeusia (≥ severe dysgeusia) was 86% (n = 12) versus 14% (n = 2) of patients, respectively; 14% (n = 2) versus 86% (n =12) at the end of TORT (P < .01); 57% (n = 8) versus 43% (n = 6) at 1-month post-TORT (P < .01); 79% (n = 11) versus 21% (n = 3) at 3-month post-TORT (P = .23) and 93% (n = 13) versus 7% (n = 1) at 6-month post-TORT (P = .18).

Conclusion: TORT displaced OT anteriorly, lowered D_MEAN to OT, especially to OT_OUT, and facilitated rapid regaining of sense of taste at 1-month post-TORT. Patient-reported quality of taste returned to the baseline at 3-month and 6-month post-TORT. Further randomized study to verify clinical advantages with TORT for HNC is warranted.