Stereotactic body radiation therapy for melanoma and renal cell carcinoma: impact of single fraction equivalent dose on local control

<p>Abstract</p> <p>Background</p> <p>Melanoma and renal cell carcinoma (RCC) are traditionally considered less radioresponsive than other histologies. Whereas stereotactic body radiation therapy (SBRT) involves radiation dose intensification via escalation, we hypothesize SBRT might result in similar high local control rates as previously published on metastases of varying histologies.</p> <p>Methods</p> <p>The records of patients with metastatic melanoma (n = 17 patients, 28 lesions) or RCC (n = 13 patients, 25 lesions) treated with SBRT were reviewed. Local control (LC) was defined pathologically by negative biopsy or radiographically by lack of tumor enlargement on CT or stable/declining standardized uptake value (SUV) on PET scan. The SBRT dose regimen was converted to the single fraction equivalent dose (SFED) to characterize the dose-control relationship using a logistic tumor control probability (TCP) model. Additionally, the kinetics of decline in maximum SUV (SUV_max) were analyzed.</p> <p>Results</p> <p>The SBRT regimen was 40-50 Gy/5 fractions (n = 23) or 42-60 Gy/3 fractions (n = 30) delivered to lung (n = 39), liver (n = 11) and bone (n = 3) metastases. Median follow-up for patients alive at the time of analysis was 28.0 months (range, 4-68). The actuarial LC was 88% at 18 months. On univariate analysis, higher dose per fraction (p < 0.01) and higher SFED (p = 0.06) were correlated with better LC, as was the biologic effective dose (BED, p < 0.05). The actuarial rate of LC at 24 months was 100% for SFED ≥45 Gy v 54% for SFED <45 Gy. TCP modeling indicated that to achieve ≥90% 2 yr LC in a 3 fraction regimen, a prescription dose of at least 48 Gy is required. In 9 patients followed with PET scans, the mean pre-SBRT SUV_maxwas 7.9 and declined with an estimated half-life of 3.8 months to a post-treatment plateau of approximately 3.</p> <p>Conclusions</p> <p>An aggressive SBRT regimen with SFED ≥ 45 Gy is effective for controlling metastatic melanoma and RCC. The SFED metric appeared to be as robust as the BED in characterizing dose-response, though additional studies are needed. The LC rates achieved are comparable to those obtained with SBRT for other histologies, suggesting a dominant mechanism of in vivo tumor ablation that overrides intrinsic differences in cellular radiosensitivity between histologic subtypes.</p

Consensus Guidelines for Delineation of Clinical Target Volume for Intensity-Modulated Pelvic Radiotherapy in Postoperative Treatment of Endometrial and Cervical Cancer

To develop an atlas of the clinical target volumes (CTV) definitions for the post-operative radiotherapy of endometrial and cervical cancer to be utilized for planning pelvic Intensity Modulated Radiation Therapy (IMRT)

Consensus Report From the Miami Liver Proton Therapy Conference

An international group of 22 liver cancer experts from 18 institutions met in Miami, Florida to discuss the optimal utilization of proton beam therapy (PBT) for primary and metastatic liver cancer. There was consensus that PBT may be preferred for liver cancer patients expected to have a suboptimal therapeutic ratio from XRT, but that PBT should not be preferred for all patients. Various clinical scenarios demonstrating appropriateness of PBT vs. XRT were reviewed

Association of Radiotherapy Duration With Clinical Outcomes in Patients With Esophageal Cancer Treated in NRG Oncology Trials: A Secondary Analysis of NRG Oncology Randomized Clinical Trials

IMPORTANCE: For many types of epithelial malignant neoplasms that are treated with definitive radiotherapy (RT), treatment prolongation and interruptions have an adverse effect on outcomes. OBJECTIVE: To analyze the association between RT duration and outcomes in patients with esophageal cancer who were treated with definitive chemoradiotherapy (CRT). DESIGN, SETTING, AND PARTICIPANTS: This study was an unplanned, post hoc secondary analysis of 3 prospective, multi-institutional phase 3 randomized clinical trials (Radiation Therapy Oncology Group [RTOG] 8501, RTOG 9405, and RTOG 0436) of the National Cancer Institute-sponsored NRG Oncology (formerly the National Surgical Adjuvant Breast and Bowel Project, RTOG, and Gynecologic Oncology Group). Enrolled patients with nonmetastatic esophageal cancer underwent definitive CRT in the trials between 1986 and 2013, with follow-up occurring through 2014. Data analyses were conducted between March 2022 to February 2023. EXPOSURES: Treatment groups in the trials used standard-dose RT (50 Gy) and concurrent chemotherapy. MAIN OUTCOMES AND MEASURES: The outcomes were local-regional failure (LRF), distant failure, disease-free survival (DFS), and overall survival (OS). Multivariable models were used to examine the associations between these outcomes and both RT duration and interruptions. Radiotherapy duration was analyzed as a dichotomized variable using an X-Tile software to choose a cut point and its median value as a cut point, as well as a continuous variable. RESULTS: The analysis included 509 patients (median [IQR] age, 64 [57-70] years; 418 males [82%]; and 376 White individuals [74%]). The median (IQR) follow-up was 4.01 (2.93-4.92) years for surviving patients. The median cut point of RT duration was 39 days or less in 271 patients (53%) vs more than 39 days in 238 patients (47%), and the X-Tile software cut point was 45 days or less in 446 patients (88%) vs more than 45 days in 63 patients (12%). Radiotherapy interruptions occurred in 207 patients (41%). Female (vs male) sex and other (vs White) race and ethnicity were associated with longer RT duration and RT interruptions. In the multivariable models, RT duration longer than 45 days was associated with inferior DFS (hazard ratio [HR], 1.34; 95% CI, 1.01-1.77; P = .04). The HR for OS was 1.33, but the results were not statistically significant (95% CI, 0.99-1.77; P = .05). Radiotherapy duration longer than 39 days (vs ≤39 days) was associated with a higher risk of LRF (HR, 1.32; 95% CI, 1.06-1.65; P = .01). As a continuous variable, RT duration (per 1 week increase) was associated with DFS failure (HR, 1.14; 95% CI, 1.01-1.28; P = .03). The HR for LRF 1.13, but the result was not statistically significant (95% CI, 0.99-1.28; P = .07). CONCLUSIONS AND RELEVANCE: Results of this study indicated that in patients with esophageal cancer receiving definitive CRT, prolonged RT duration was associated with inferior outcomes; female patients and those with other (vs White) race and ethnicity were more likely to have longer RT duration and experience RT interruptions. Radiotherapy interruptions should be minimized to optimize outcomes

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The dosimetric effect of inhomogeneity correction i

Stereotactic Body Radiation Therapy

XXV, 421 p. 120 illus. in color.online resource

Radiation therapy oncology group gynecologic oncology working group: comprehensive results

The purpose of this report was to comprehensively describe the activities of the Gynecologic Oncology Working Group within the Radiation Therapy Oncology Group (RTOG). Clinical trials will be reviewed as well as translational science and ancillary activities. During the past 40 years, a myriad of clinical trials have been performed within the RTOG with the aim of improving overall survival (OS) and decreasing morbidity in women with cervical or endometrial cancer. Major study questions have included hyperbaric oxygen, neutron radiotherapy, altered fractionation, hypoxic cell sensitization, chemosensitization, and volume-directed radiotherapy.RTOG 7920 demonstrated improvement in OS in patients with stages IB through IIB cervical carcinoma receiving prophylactic para-aortic irradiation compared to pelvic radiation alone. RTOG 9001 demonstrated that cisplatin and 5-FU chemoradiotherapy to the pelvis for advanced cervix cancer markedly improved OS compared to extended field radiotherapy alone. More recent trials have used radioprotectors, molecular-targeted therapy, and intensity-modulated radiation therapy. Ancillary studies have developed clinical target volume atlases for research protocols and routine clinical use. Worldwide practice patterns have been investigated in cervix, endometrial, and vulvar cancer through the Gynecologic Cancer Intergroup. Translational studies have focused on immunohistochemical markers, changes in gene expression, and miRNA patterns impacting prognosis.The RTOG gynecologic working group has performed clinical trials that have defined the standard of care, improved survival, and added to our understanding of the biology of cervical and endometrial cancers