U. Tebano

Stereotactic Ablative Radiation Therapy for Lung Oligometastases: Predictive Parameters of Early Response by (18)FDG-PET/CT

Objectives: The objective of this study was to investigate fludeoxyglucose F 18 positron emission tomography/computed tomography (18FDG‐PET/CT) parameters as predictive of response after stereotactic ablative radiotherapy (SABR) for lung oligometastases. Methods: The inclusion criteria of the current retrospective study were as follows: (1) lung oligometastases treated by SABR, (2) presence of 18FDG‐PET/CT before and after SABR for at least two subsequent evaluations, (3) Karnofsky performance status higher than 80, and (4) life expectancy longer than 6 months. All patients were treated with a biologically equivalent dose of at least 100 Gy with an alpha/beta ratio of 10. The following metabolic parameters were semiquantitatively defined: maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), metabolic tumor volume, and total lesion glycolysis. Results: A total of 50 patients met the inclusion criteria, for a total of 70 lung metastases. The pre‐SABR median SUVmax was 6.5 (range 4–17), the median SUVmean was 3.7 (range 2.5–6.5), and the median metabolic tumor volume was 2.3 cm3 (0.2–31 cm3). The following metabolic parameters were significantly related to complete response at 6 months: SUVmax less than 5 (p < 0.001) and SUVmean less than 3.5 (p = 0.03). &Dgr;SUVmax at 3 to 6 months was +126% for lesions with in‐field progression versus –26% for the remaining lesions (p = 0.002). &Dgr;SUVmean at 3 to 6 months was +15% for lesions with in‐field progression versus –26% for the remaining metastases (p = 0.008). Conclusions: In the current analysis, complete response from lung metastasis at 6 months after stereotactic body radiation therapy was significantly associated with both the maximum and mean values of pre‐SABR 18FDG‐PET/CT SUV. Longer‐term trials are strongly advocated to improve the personalization of the monitoring of tumor response in patients with lung oligometastases and, consequently, monitoring of the cost‐effectiveness of the health care.

Moderate Hypofractionated Postprostatectomy Volumetric Modulated Arc Therapy With Daily Image Guidance (VMAT-IGRT): A Mono-institutional Report on Feasibility and Acute Toxicity

Introduction The aim of this study was to evaluate the acute toxicity profiles of a moderate hypofractionated regimen with volumetric modulated arc therapy (VMAT) in patients with prostate cancer (PC) who underwent radical prostatectomy. Material and Methods From December 2012 to February 2016, 125 patients, previously having undergone radical prostatectomy, received adjuvant (64 patients) or salvage (61 patients) radiotherapy (RT) inside an institutional protocol of moderate hypofractionation schedule using the VMAT technique (Varian RapidArc, Palo Alto, CA). Eligible patients were < 85 years old, with an Eastern Cooperative Oncology Group performance status of 0 to 2, histologically proven adenocarcinoma of the prostate without distant metastases, and pathologic stage pT2‐4 N0‐1, with at least 1 of the following risk factors: capsular perforation, positive surgical margins, seminal vesicle invasion, and/or postoperative prostate‐specific antigen > 0.2 ng/mL. Patients were stratified into low (1%), intermediate (9%), and high‐risk (90%) groups. The median age was 68 years. The median doses were 66 Gy (range, 65.5‐71.4 Gy) to the prostatic bed and 52.5 Gy (range, 50.4‐54 Gy) to the pelvic lymph nodes, in 28 or 30 fractions. The acute genitourinary (GU) and gastrointestinal (GI) toxicities were scored according to the Common Terminology Criteria for Adverse Events, v4. Results All 125 patients completed the planned treatment, with good tolerance. After RT, the median follow‐up was 18 months. Acute toxicities were recorded for the GU (G0, 45/125 [36%]; G1, 63/125 [50.4%]; G2, 16/125 [12.8%]; G3, 1/125 [0.8%]) and the GI (G0, 42/125 [33.6%]; G1, 72/125 [57.6%]; G2, 11/125 [8.8%]; no G3). Analyzing data according to RT intent, a higher rate of GU toxicity ≥ 2 was found in the adjuvant setting (17.1%) with respect to the salvage group (9.8%); P = .01 with the Fisher exact text. Furthermore, at statistical analysis, no difference was found between the type of surgery (robotic, laparoscopic, or open) and incidence of urinary incontinence (P = .8). The actuarial Kaplan‐Meier rates for biochemical disease‐free survival were 94% and 77% for adjuvant and salvage RT, at 36 months. Conclusions Moderate hypofractionated postoperative RT with VMAT was feasible and safe with acceptable acute GU and GI toxicities. Longer follow‐up is needed to assess late toxicity and clinical outcomes. Micro‐Abstract In prostate cancer, moderate hypofractionated postoperative radiotherapy with the volumetric modulated arc therapy technique is a promising option. Our series seems to confirm the feasibility and the good acute genitourinary and gastrointestinal toxicity profile comparable with conventional fractionation schedules. Longer follow‐up is needed to evaluate late toxicity and clinical outcomes.

Simultaneous Integrated Bilateral Breast and Nodal Irradiation with Volumetric arc Therapy: Case Report and Literature Review:

Aim For simultaneous bilateral breast cancer (SBBC) treatment, conventional radiotherapy (RT) has a number of critical shortcomings. Thus, the usefulness of volumetric arc therapy (VMAT) for SBBC is undeniable. Case Report A 34-year-old woman with SBBC received neoadjuvant chemotherapy followed by breast-conserving surgery and bilateral lymph node dissection. Given the conservative surgery and the nodal involvement after neoadjuvant chemotherapy, bilateral adjuvant RT to the breasts and regional nodes with doses of 50 Gy in 25 fractions and a simultaneous integrated boost (SIB) of 60 Gy to the surgical bed was proposed. Monoisocentric VMAT using 2 pairs of arcs was performed with adequate target dose coverage and low doses to the organs at risk. The results of this case were compared with those of previous studies in terms of RT technique and irradiated volumes. Conclusions VMAT is feasible and safe in the treatment of SBBC with SIB and nodal irradiation.

Hippocampal dose during Linac-based stereotactic radiotherapy for brain metastases: An observational study

INTRODUCTION Aim of the present study is to evaluate homolateral and contralateral hippocampus (H-H, C-H, respectively) dose during Fractionated Stereotactic Radiotherapy (FSRT) or Radiosurgery (SRS) for brain metastases (BM). MATERIALS & METHODS Patients with BM<5, size≤30mm, KPS≥80 and a life expectancy>3months, were considered for SRS/FSRT (total dose 15-30Gy, 1-5 fractions). For each BM, a Flattening Filter Free (FFF) Volumetric Modulated Arc Therapy (VMAT) plan was generated with one or two arcs. Hippocampi were not considered during optimizations phase and were contoured and evaluated retrospectively in terms of dose: the Dmedian, Dmean, D0.1cc and the V1Gy, V2Gy, V5Gy and V10Gy were analyzed. RESULTS From April 2014 to December 2015, 81 BM were treated with FFF-FSRT/SRS. For the H-H, the average values of Dmedian, Dmean and D0.1cc were 1.5Gy, 1.54Gy and 2.2Gy, respectively, while the V1Gy, V2Gy, V5Gy and V10Gy values were 25%, 8.9%, 8.9% and 2.1%, respectively. For the C-H, the average Dmedian, Dmean and D0.1cc were 0.7Gy, 0.7Gy, 0.9Gy, respectively, while the average values of V1Gy, V2Gy, V5Gy and V10Gy were 18%, 10.2%, 2.8% and 1.4%, respectively. Tumor dimension, tumor cranial-caudal length and the distance between BM and H-H were correlated to Dmedian, Dmean and D0.1cc. For C-H, only the distance from PTV was correlated with a dose reduction. CONCLUSION During FFF-FSRT/SRS, hippocampus received a negligible dose. Despite its clinical significance is still under evaluation, in patients with a long life expectancy, H-H should be considered during Linac-based FSRT/SRS.

Increased efficacy of stereotactic ablative radiation therapy after bevacizumab in lung oligometastases from colon cancer

Aim: Metastases from colorectal cancer are poorly responsive to stereotactic ablative radiation therapy (SABR) due to intratumoral hypoxia. Intratumoral oxygenation is improved by administration of angiogenesis inhibitors. Thus, there could be a clinical synergistic effect of SABR with bevacizumab on metastases from colorectal cancer. The aim of this study was to evaluate the feasibility and efficacy of SABR after bevacizumab in lung oligometastases from colon cancer. Methods: The data of patients with lung metastases from colon cancer who underwent SABR were retrospectively evaluated according to the following inclusion criteria: number of metastases ≤3; lung oligometastases from colon cancer in patients who underwent SABR; patients receiving previous chemotherapy alone or in combination with bevacizumab; Karnofsky performance status >80; life expectancy >6 months; at least 6 months’ follow-up after SABR; presence of KRAS mutation. The results were compared with those of a similar cohort of patients with irradiated lung lesions from colorectal cancer in whom bevacizumab was not previously administered. Results: A total of 40 lung metastases were analyzed. The complete response rate after SABR was higher in patients who had received bevacizumab than in those who had not (p = 0.04). Additionally, in the bevacizumab group, a higher rate of post-SABR complete response was observed in case of oligopersistent versus oligorecurrent metastases (p = 0.001). Conclusions: In the setting of lung oligometastases from colon cancer the present study attested the higher efficacy of SABR after bevacizumab administration. Further studies in this field of research are strongly advocated.