The Evolving Interplay of SBRT and the Immune System, along with Future Directions in the Field

Response of Spontaneous Oral Tumors in Canine Cancer Patients Treated with Stereotactic Body Radiation Therapy (SBRT)

The objective of this study is describe outcome and toxicity for dogs with oral tumors, specifically oral malignant melanoma (OMM), squamous cell carcinoma (SCC), and soft tissue sarcoma (STS) after stereotactic body radiation therapy (SBRT). A single institution retrospective study was conducted. Outcomes were analyzed using Kaplan-Meier analysis and Cox proportional hazard analysis. Treatment responses at different time points were evaluated with Pearson's Chi-squared test to identify prognostic factors. Acute and late toxicities were recorded according to VRTOG criteria and were analyzed to identify risk factors. Adverse events other than acute and late toxicities were recorded. A total of 98 patients met the inclusion criteria (OMM n = 37; SCC n = 18; STS n = 43). The SBRT prescription was 1-6 fractions, with a total dose range of 12-40 Gy. Local progression-free survival (PFS) for OMM, SCC, and STS was 187, 253, and 161 days, respectively. Overall PFS was 152 days and median survival time (MST) was 270 days, with no statistical difference between tumor types. The presence of lymph node metastasis and the use of elective nodal irradiation (ENI) were associated with shorted PFS and MST. Severe acute toxicities to organs at risk affected 10/85 (11.8%) of patients. Osteoradionecrosis and oronasal fistula formation occurred in 23/81 (28.4%) of patients and was significantly associated with tumor type (SCC, P = 0.006). SBRT can be offered as a treatment option for oral tumors in dogs. Toxicities were common and warrant risk factor considerations and adjustments to current SBRT protocols.

Adaptive Stereotactic Body Radiation Therapy in the Management of Oligometastatic Uterine Leiomyosarcoma: A Clinical Case Report

Safe delivery of stereotactic body radiation therapy (SBRT) to large (>5 cm) oligometastatic abdominopelvic tumors can often be challenging, especially in tumors that require a higher biologically effective dose (BED) for tumor control. Adaptive stereotactic body radiation therapy (A-SBRT) involves inter-fraction and real-time replanning while the patient is on the treatment table, potentially allowing for improved dose coverage and greater sparing of critical structures. Our case report illustrates the benefit of CT-based A-SBRT in the treatment and management of an oligometastatic uterine leiomyosarcoma patient with a rapidly enlarging pelvic recurrence. A 60-year-old female presented to the radiation oncology clinic for treatment of an enlarging, right pelvic oligometastatic leiomyosarcoma. She was prescribed 35 Gy in five fractions. Planning prioritized the sparing of nearby small bowels while maximizing coverage of the planning target volume (PTV). On treatment day, two plans were calculated, the initial plan recalculated on the current CBCT (scheduled plan) and a plan reoptimized using current contours (adapted plan), and the more appropriate one was chosen for delivery. The adapted plan was chosen for all five fractions, with the adapted plan offering better small bowel sparing in five fractions and better target coverage in four fractions, delivering a total of 34 Gy to 95% of the PTV while limiting the small bowel to a maximum point dose of 37 Gy. At approximately six months out from treatment, the patient showed continued radiographic response and resolved acute Grade 1 gastrointestinal toxicity. This case study therefore demonstrates the successful treatment of a large oligometastatic abdominopelvic tumor using CT-based A-SBRT and builds on previous experience treating abdominal cases adaptively.

Stereotactic central/core ablative radiation therapy: results of a phase I study of a novel strategy to treat bulky tumor

Purpose

Bulky tumor remains as a challenge to surgery, chemotherapy and conventional radiation therapy. Hence, in efforts to overcome this challenge, we designed a novel therapeutic paradigm via strategy of Stereotactic Central/Core Ablative Radiation Therapy (SCART).), which is based on the principles of SBRT (stereotactic body radiation therapy and spatially fractionated radiation therapy (SFRT). We intend to safely deliver an ablative dose to the core of the tumor and with a low dose at tumor edge. The purpose of the phase 1 study was to determine dose-limiting toxicities (DLT)s and the Maximum Tolerated Dose (MTD) of SCART.

Methods and materials

We defined a SCART-plan volume inside the tumor, which is proportional to the dimension of tumor. VMAT/Cyberknife technique was adopted. In the current clinical trial; Patients with biopsy proven recurrent or metastatic bulky cancers were enrolled. The five dose levels were 15 Gy X1, 15Gy X3, 18GyX3, 21GyX3 and 24GyX3, while keeping the whole tumor GTV's border dose at 5Gy each fraction. There was no restriction on concurrent systemic chemotherapy agents.

Results

21 patients were enrolled and underwent SCART. All 21 patients have eligible data for study follow-up. Radiotherapy was well tolerated with all treatment completed as scheduled. The dose was escalated for two patients to 24GyX3. No grade 3 or higher toxicity was observed in any of the enrolled patients. The average age of patients was 66 years (range: 14-85) and 13 (62%) patients were male. The median SCART dose was 18Gy (range: 15 - 24). Six out of the 18 patients with data for overall survival (OS) died, and the median time to death was 16.3 months (range: 1 - 25.6). The mean percent change for tumor shrinkage between first visit volumes and post-SCART volumes was 49.5% (SD: 40.89, p-value:0.009).

Conclusion

SCART was safely escalated to 24 GyX 3 fractions, which is the maximum Tolerated Dose (MTD) for SCART. This regimen will be used in future phase II trials.

Phase II Trial of Concurrent Nivolumab and Radiation Therapy for Muscle-Invasive Bladder Cancer of Older or Chemotherapy-Ineligible Patients

PURPOSE

Bladder cancer is predominantly a disease of older individuals. Concurrent chemotherapy and radiation is a bladder-sparing strategy for management of muscle-invasive bladder cancer; however, many patients are not candidates for chemotherapy due to comorbidities or impaired performance status. We conducted a study in a chemotherapy-ineligible patient population with the objectives of evaluating the safety, efficacy, and quality-of-life effect of the combination of nivolumab and radiation therapy in patients with localized/locally advanced urothelial cancer.

METHODS AND MATERIALS

Eligible patients had muscle-invasive bladder cancer and were not candidates for standard chemoradiation strategy due to at least one of the following: performance status of 2, creatinine clearance ≤60 mL/min, cardiac disease, neuropathy, and intolerance to previous treatment. Creatinine clearance ≥40 mL/min, normal marrow, and liver function were required. The primary endpoint was progression-free survival at 12 months. Nivolumab was started within 3 days of radiation therapy and administered at a dose of 240 mg intravenously every 2 weeks for a maximum of 6 months. Radiation therapy was per standard of care for bladder cancer. Imaging and cystoscopy and biopsy evaluation were required at months 3, 6, and 12 and then annually until progression.

RESULTS

Twenty patients were enrolled, with a median age of 78.5 years (range, 58-95 years); 80% of patients were >70 years of age, and 8 (40%) were >80 years of age. Median creatinine clearance was 52 mL/min. Nine patients (48%) were progression free at 12 months. Median progression-free survival was 11.4 months (90% CI, 7.5-23.7 months), and median overall survival was 15.6 months (90% CI, 9.1-26.1 months).

CONCLUSIONS

Concurrent nivolumab and radiation therapy is tolerable but demonstrated limited efficacy in an older population with multiple comorbidities. Immune correlates demonstrated that patients with baseline programmed cell death ligand 1 combined prognostic score ≥5% had numerically longer progression-free survival.

[A Case of New Rapidly Progressing Ground-glass Nodule Lung Adenocarcinoma Near Primary Lesion after Stereotactic Body Radiation Therapy]

Ground-glass nodule (GGN) lung cancer often progresses slowly in clinical and there are few clinical studies on long-term follow-up of patients with operable GGN lung cancer treated with stereotactic body radiation therapy (SBRT). We present a successful case of GGN lung cancer treated with SBRT, but a new GGN was found in the lung adjacent to the SBRT target during follow-up. The nodule progressed rapidly and was confirmed as lung adenocarcinoma by surgical resection. No significant risk factors and related driving genes were found in molecular pathological findings and genetic tests. It deserves further study whether new GGN is related to the SBRT. This case suggests that the follow-up after SBRT should be vigilant against the occurrence of new rapidly progressive lung cancer in the target area and adjacent lung tissue.
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Tata Memorial Centre Evidence Based Management of Breast cancer

ABSTRACT

The incidence of breast cancer is increasing rapidly in urban India due to the changing lifestyle and exposure to risk factors. Diagnosis at an advanced stage and in younger women are the most concerning issues of breast cancer in India. Lack of awareness and social taboos related to cancer diagnosis make women feel hesitant to seek timely medical advice. As almost half of women develop breast cancer at an age younger than 50 years, breast cancer diagnosis poses a huge financial burden on the household and impacts the entire family. Moreover, inaccessibility, unaffordability, and high out-of-pocket expenditure make this situation grimmer. Women find it difficult to get quality cancer care closer to their homes and end up traveling long distances for seeking treatment. Significant differences in the cancer epidemiology compared to the west make the adoption of western breast cancer management guidelines challenging for Indian women. In this article, we intend to provide a comprehensive review of the management of breast cancer from diagnosis to treatment for both early and advanced stages from the perspective of low-middle-income countries. Starting with a brief introduction to epidemiology and guidelines for diagnostic modalities (imaging and pathology), treatment has been discussed for early breast cancer (EBC), locally advanced, and MBC. In-depth information on loco-regional and systemic therapy has been provided focusing on standard treatment protocols as well as scenarios where treatment can be de-escalated or escalated.

Treatment Landscape of Renal Cell Carcinoma

OPINION STATEMENT

The treatment landscape of renal cell carcinoma (RCC) has evolved significantly over the past three decades. Active surveillance and tumor ablation are alternatives to extirpative therapy in appropriately selected patients. Stereotactic body radiation therapy (SBRT) is an emerging noninvasive alternative to treat primary RCC tumors. The advent of immune checkpoint inhibitors (ICIs) has greatly improved the overall survival of advanced RCC, and now the ICI-based doublet (dual ICI-ICI doublet; or ICI in combination with a vascular endothelial growth factor tyrosine kinase inhibitor, ICI-TKI doublet) has become the standard frontline therapy. Based on unprecedented outcomes in the metastatic with ICIs, they are also being explored in the neoadjuvant and adjuvant setting for patients with high-risk disease. Adjuvant pembrolizumab has proven efficacy to reduce the risk of RCC recurrence after nephrectomy. Historically considered a radioresistant tumor, SBRT occupies an expanding role to treat RCC with oligometastasis or oligoprogression in combination with systemic therapy. Furthermore, SBRT is being investigated in combination with ICI-doublet in the advanced disease setting. Lastly, given the treatment paradigm is shifting to adopt ICIs at earlier disease course, the prospective studies guiding treatment sequencing in the post-ICI setting is maturing. The effort is ongoing in search of predictive biomarkers to guide optimal treatment option in RCC.

Risk factors of local control in adrenal metastases treated by stereotactic body radiation therapy - a systematic review and meta-analysis

Purpose

This study is aimed to explore risk factors affect the therapy outcomes of adrenal metastases (AM) for stereotactic body radiation therapy (SBRT) and guide clinical dose selection.

Methods and materials

PubMed, Embase and Web of Science were searched in September 22, 2022 in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA). Subgroup analysis and meta-regression were used to search for sources of heterogeneity and identify risky outcomes factors. Publication bias test and sensitivity analysis were also conducted.

Results

Thirty-three studies with full text from 2009 to 2022 about AM with SBRT on 1483 patients were included. Pooled 1- and 2-year local control (LC) and overall survival(OS) were 81.7% (95% confidence interval [CI], 75.6%-86.5%), 62.8% (95% CI, 53.8%-71.8%), 67.4% (95%CI, 61.8%-73.1%) and 46.5% (95%CI, 40.4%-52.6%), respectively. Biological effective dose (BED, α/β=10Gy) and dose per fraction affected 1-year LC (Qm=23.89, 15.10; P<0.0001, 0.0001). In the range of 60-80Gy (BED10), the group of dose per fraction ≥ 9Gy achieved the excellent 1-year LC (< 9Gy: ≥ 9Gy =78%, 91%; χ2 = 10.16, P = 0.001). Tracking technology significantly affected 1- and 2-year OS (Qm = 5.73, 8.75; P = 0.017, 0.003) and high tracking adoption group showed excellent 1- and 2- year OS (78.7% [95%CI, 68.6%- 88.9%]; and 62.9% [95%CI, 53.1%-72.7%]).

Conclusion

Increasing the dose per fraction appropriately may help control locally AM lesious. Tracking technology might contribute to improve survival of advanced patients with AM. But these results need prospective studies to verify them.

Definitive ablative stereotactic partial breast irradiation in early stage inoperable breast cancer

PURPOSE

This case series and literature review aims to investigate the efficacy and safety of definitive ablative radiation therapy as a treatment modality for non-operable patients with early stage breast cancer. We present two cases demonstrating the potential of this approach to achieve durable responses.

METHODS

We assessed the long-term response of two non-operable patients diagnosed with Stage II (cT2N0M) and Stage IA (T1bN0M0) invasive ductal carcinoma (IDC), who were deemed unfit for surgery due to significant co-morbid conditions. Definitive ablative radiation therapy was administered using stereotactic partial breast irradiation with ablative doses delivered in either a single fraction or two fractions. Serial imaging was conducted to assess treatment response and monitor adverse events.

RESULTS

Both patients exhibited notable treatment responses following definitive ablative radiation therapy. The first patient, an 84-year-old woman, experienced a 69% reduction in tumor size over a follow-up period exceeding 2 years. The second patient, an 87-year-old woman, achieved complete resolution of disease on imaging, with no signs of progression even 26 month post-treatment. Both patients tolerated the treatment well, without significant treatment-related adverse events.

CONCLUSIONS

Our case series suggests that definitive ablative radiation therapy may serve as a safe and effective treatment option for non-operable patients with early stage breast cancer. The observed durable treatment responses and minimal toxicity support the potential of this approach. Furthermore, a longer interval between ablative radiation therapy and surgery may enhance treatment response, potentially leading to increased complete pathologic response rates.

Comparison of Recurrence Patterns between Adenocarcinoma and Squamous Cell Carcinoma after Stereotactic Body Radiotherapy for Early-Stage Lung Cancer

We compared recurrence patterns between adenocarcinoma (ADC) and squamous cell carcinoma (SCC) after stereotactic body radiotherapy (SBRT) for early-stage lung cancer. Patients with ADC and SCC histology, who were treated with SBRT for clinical stage IA1-IIA lung cancer at our institution, were included in the analysis. The rates of disease-free survival (DFS), overall survival (OS), local recurrence (LR), lymph node metastasis (LNM), and distant metastasis (DM) were calculated using the Kaplan-Meier method or the cumulative incidence function. Among the 204 patients analyzed, 138 and 66 were in the ADC and SCC groups, respectively. The median follow-up period was 60 months. The five-year DFS and OS rates were 57% vs. 41% and 69% vs. 48% in the ADC and SCC groups, respectively (p = 0.015 and 0.019, respectively). In the multivariate analysis, the histological type was not associated with DFS or OS. Five-year LR, LNM, and DM rates were 10% vs. 24%, 12% vs. 20%, and 25% vs. 27% in the ADC and SCC groups, respectively (p = 0.0067, 0.074, and 0.67, respectively). The multivariate analysis identified the histological type of SCC as an independent factor for LR (hazard ratio, 2.41; 95% confidence interval, 1.21-4.77; p = 0.012). The present results suggest that the risk of LR after SBRT is higher for SCC than for ADC.