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Algorithms for the treatment of prostate cancer (PrCa) rely on risk grouping, and those who fall into low (LR) and favourable intermediate risk (FIR) categories have multiple options for treatment. High-intensity focused ultrasound (HiFU) is a local treatment modality that uses ultrasound waves to ablate prostate cancer. In case of treatment failure, optimal salvage modality after HiFU remains unclear.Here, we describe a retrospective review of our regional cancer database for men who underwent salvage radiotherapy after failure of HiFU treatment for prostate cancer. Oncologic and toxicity outcomes of the men identified in our database are discussed.We identified 14 men in our regional database who received salvage radiotherapy (70-74 Gy with or without androgen deprivation therapy (ADT) after primary HiFU, in the period of 2009-2017. No cases of any grade 3 or higher toxicity were observed. In our cohort, 50% (7/14) of patients developed secondary biochemical failure at a median follow-up of 54 months post-radiotherapy, with a mean time to biochemical failure of 39 months. We compare our data to other available reports to date consisting mostly of small, non-randomized studies. Our biochemical control rates are noticeably lower compared with those reported by other studies but our length of follow-up is longer, compared with other studies.The available data to date suggest that salvage radiotherapy after HiFU failure is well-tolerated albeit with only modest efficacy.

During radiation therapy treatments patients may require medications to manage radiation toxicities. Since patients are assessed daily by Radiation Therapists (RTs) it would be optimal and timely for patients to receive medication prescriptions for relief of common radiation side effects from the RTs.The purpose of this study was to determine the perceptions that RTs and Radiation Oncologists (ROs) have of frontline treatment RTs prescribing medications to patients for treatment-related side effects.A qualitative and quantitative survey consisting of twenty-five questions on a five-point Likert scale, one open-ended question, and three demographic questions was designed. While the survey sought to examine the perceptions that RTs and ROs have of RTs prescribing medications, the survey also proposed eight different medications that RTs could potentially prescribe. The medications that were proposed are commonly prescribed to radiation therapy patients and included anti-emetic, topical anti-bacterial, hydrocortisone cream, topical anaesthetic, anti-diarrheal, anti-spasmodic, urinary analgesic and anti-fungal medications. After the survey was approved by the Research Ethics Board, RTs and ROs at a large, academic cancer centre were invited to complete the survey. To analyze the survey results, several statistical tests were performed separately for the RTs' surveys and the ROs' surveys. The chi-squared test was used to determine if the sample RT and RO populations were representative of the actual RT and RO populations (p0.05). Additionally, the Sign test for medians was used to analyze statistically the responses to the Likert scale questions (p0.05), while the Kruskal-Wallis test was used to compare the responses to the Likert scale questions across the demographic groups identified in the demographic questions (p0.05).The response rate was 34% (31/90) for the RT population and 42% (10/24) for the RO population. The statistical analysis of the RT population's surveys showed that the majority of the RTs shared positive perceptions towards having RTs prescribe medications, while some respondents highlighted negative perceptions in the open-ended qualitative question. The majority of the RTs agreed that RTs should prescribe five of the eight proposed medications, excluding anti-spasmodic, urinary analgesic, and anti-fungal medications. In contrast to the RTs, there was no statistically significant consensus from the ROs on RTs prescribing medications. Furthermore, the ROs had varying opinions on RTs prescribing the eight proposed medications.Although the sample size in this study was small, the results from the RT population's surveys supported RTs prescribing medications. The positive results from the RTs and the equivocal response from the ROs suggest that future research should be conducted. Additionally, a future pilot study could be implemented where RTs prescribe one or more of the five medications that were supported to prescribe by the RTs. By having RTs prescribe medications to patients in a pilot study, the effectiveness on patient care could be measured.

There is increasing interest in using stereotactic body radiation therapy (SBRT) in areas of oligoprogressive metastatic disease (OPD). Our main objective was to investigate the impact of SBRT on overall survival (OS) and the incidence of systemic therapy treatment switches in this population.A retrospective institutional review of patients treated with SBRT for OPD was performed. Patients were included if they received SBRT for 1-3 discrete progressing metastases, using a dose of at least 5 Gy per fraction. The study aimed to calculate progression-free survival (PFS), overall survival (OS), local control (LC), and incidence of treatment switch (TS). PFS and OS were calculated using the Kaplan-Meier methodology, while LC and TS were determined using cumulative incidence.Eighty-one patients with a total of 118 lesions were treated with SBRT from July 2014 to November 2020. The Median SBRT dose was 40 (18-60) Gy in 5 (2-8) fractions. Patients had primarily kidney, lung, or breast cancer. Most patients were treated with a tyrosine kinase inhibitor (TKI) (30.9%) or chemotherapy (29.6%) before OPD. The median follow-up post-SBRT was 14 months. Median OS and PFS were 25.1 (95% CI 11.2-39.1) months and 7.8 (95% CI 4.6-10.9) months, respectively. The cumulative incidence of local progression of treated lesions was 5% at 1 year and 7.3% at 2 years. Sixty patients progressed after SBRT and 17 underwent additional SBRT. Thirty-eight patients (47%) changed systemic therapy following SBRT; the cumulative incidence of TS was 28.5% at 6 months, 37.4% at 1 year, and 43.9% at 2 years.SBRT effectively controls locally progressing lesions but distant progression still occurs frequently. A sizeable number of patients can be salvaged by further SBRT or have minimally progressing diseases that may not warrant an immediate initiation/switch in systemic therapy. Further prospective studies are needed to validate this benefit.

363 Background: SBRT uses highly conformal radiotherapy to deliver high dose per fraction treatment. Advantages of SBRT include short treatment times, decreased costs and limited toxicity. Randomized trial outcomes of 7-fraction SBRT for low or intermediate PrCa were reported but results of studies that compared 5-fraction SBRT with conventional and HFRT are pending. Here, we reviewed the 12-year experience with SBRT and HFRT at the Juravinski and Walker Family Cancer Centers in Ontario. Methods: We reviewed patients with low or intermittent-risk PrCa treated with SBRT alone or HFRT alone in the period of July 2010 and February 2022. Database search criteria included treatments with SBRT 35-40Gy in 5 fractions and HFRT 60-62Gy in 20 fractions. Overall survival (OS), time to biochemical failure (per Phoenix criteria: i.e., 2ng/mL above PSA nadir) and biochemical failure-free survival (bFFS) were reviewed. Kaplan-Meier curves were used to assess OS and bFFS. Results: We identified 314 patients with low or intermediate-risk PrCa who were treated with SBRT and 258 patients who were treated with HFRT. Intermediate-risk category composed 86.0% and 95.7% of the SBRT and HFRT cohorts. ISUP Grade Group (GG) distributions for the SBRT and HFRT patients were: GG1: 19.4% and 9.3%, GG2: 72.9% and 74.0%, and GG3: 7.6% and 16.7%, respectively. OS rates at 5 years were 96.6% for SBRT vs. 95.8% for HFRT-treated patients. The 5-year bFFS rates for SBRT and HFRT were 92.3% and 90.1%, respectively. The 7-year bFFS rate for the SBRT cohort was 90.2%. Mean time to biochemical failure was 40.4 months after SBRT vs. 35.8 months after HFRT. Conclusions: SBRT is an effective treatment option for low to intermediate-risk PrCa with encouraging OS and bFFS rates comparable with HFRT. Pending randomized trial results will determine whether SBRT is the new standard of care for this population.

45 Background: In Ontario, PSMA-PET is available to patients with prostate cancer who experience biochemical failure after definitive primary RT (pRT) or salvage/adjuvant RT (sRT) through a provincial registry study (PREP protocol). Here we review patterns of PSMA-PET-detected failure after primary (pRT) or salvage/adjuvant RT (sRT) radiotherapy (RT) in cohorts of PREP-registry patients from the Local Health Integration Network (LHIN) 4 region. Methods: With ethics approval, we retrospectively analyzed patients imaged with PSMA-PET in Hamilton, Ontario, Canada, after biochemical failure, following pRT or sRT. Demographic, clinical and treatment parameters as well as PSMA-PET results were collected. Results: Between April 2019 and December 2021, 104 pRT and 91 sRT patients were imaged with 18F-DCFPyL PSMA-PET. Median PSA (ng/mL) before PSMA-PET for the two groups was 5.0 (IQR:3.1-8.9) and 1.3 (IQR:0.6-3.4). The percentages of Prostate or Prostatic bed RT alone (Pr-RT) and Pr + pelvic Lymph Node RT (Pr+LN-RT) RT treatments, were Pr-RT:76% vs Pr+LN-RT:24% for the pRT group and Pr-RT:49.4% vs Pr+LN-RT:50.6% for the sRT group, respectively. Rates of PSMA-PET detected local, pelvic lymph node and distant recurrence are shown. In the pRT group, increasing D’Amico risk category (low to high risk) was associated with lower risk for local and increased risk for pelvic and distant metastasis. Pelvic RT was associated with reduce risk for local recurrence in the pRT but not in the sRT group. Conclusions: In this cohort of patients PSMA-PET detected a considerable risk for local recurrence in patient treated with pRT. A high number of patients are detected with pelvic-only disease recurrence, but pelvic RT seems to be associated with reduction in this risk only in the pRT population. Studies with PSMA-PET at baseline, before pRT or sRT, may help discern better patients that would benefit from pelvic RT and systemic therapy.[Table: see text]

Background Stereotactic Body Radiotherapy (SBRT) has shown effectiveness in treating bone metastases to alleviate pain. The benefit of SBRT may be further harnessed especially when radiating disease from primary malignancies with low alpha–beta ratios in order to maximize the magnitude and durability of pain relief. However, such an approach has not been studied in a prospective trial. We look to assess single-fraction SBRT for painful non-spinal bone metastases from radioresistant primaries. Methods Forty patients will be enrolled on an open label, phase II single arm trial to receive a single fraction of SBRT (15–20 Gray) to all sites of bone metastases requiring treatment for pain relief. Eligible patients will include those with primary malignancies consisting of prostate cancer, breast cancer, renal cell carcinoma, or melanoma. The primary endpoint is pain response at 3 months post-treatment using the Brief Pain Inventory. Secondary endpoints include pain response at 1 month and 6 months post-treatment, toxicity, patient-reported quality of life, re-irradiation or salvage surgery, and local control. Discussion This study will evaluate the efficacy of single-fraction SBRT on painful bone metastases from primary cancers with low alpha–beta ratios. These data will be valuable to promote future randomized trials and support clinical implementation. Trial registration Clinicaltrials.gov, NCT04177056. Date of registration: November 26, 2019. https://clinicaltrials.gov/ct2/show/NCT04177056

Purpose: Patients with close or positive margins after surgery for pancreatic carcinoma are at a high risk for recurrence. Stereotactic body radiation therapy (SBRT) allows for safe dose escalation with great conformity and short duration of treatment. Herein, we report the initial results of a prospective observational study that evaluated the efficacy and safety of this treatment option. Methods and Materials: Patients eligible for the study had pathologically proven T1-4N0-1M0 pancreatic adenocarcinoma with a positive margin (≤1 mm) or a close margin defined as

Purpose Stereotactic ablative radiation therapy's (SABR's) great conformity and short duration has become an attractive treatment modality. We report a phase 2 clinical trial to evaluate efficacy and safety of induction chemotherapy (ICT) followed by SABR in patient with borderline resectable (BR) and locally advanced (LA) pancreatic ductal adenocarcinoma (PDAC). Methods and materials Patients with biopsy-proven BR or LA PDAC were treated with four 21-day cycles of intravenous gemcitabine and oral capecitabine. Patients were restaged within 4 weeks after ICT by computed tomography and treated by 3-fraction SABR if no metastasis or progressive disease was identified. Patients were restaged 4 weeks following SABR to determine resectability. Tumor response was assessed with carbohydrate antigen 19-9. Results Thirty-five patients (19 BR/16 LA) were enrolled. The median age was 71.8 years (range, 50.6-81.1). ICT was completed in 91.4% (n = 32) of patients. All patients who completed ICT completed SABR. Of those 32 patients, 34.3% (n = 12: 10 BR, 2 LA) underwent pancreaticoduodenectomy and 11 of 12 (91.7%) received R0 resection. Median overall survival was 18.8, 28.3, and 14.3 months for the entire cohort, BR, and LA, respectively. The 2-year local progression-free survival (LPFS) was 44.9%, 40%, and 52% for the entire cohort, BR, and LA, respectively. For BR patients, multivariate analysis showed surgery was associated with better overall survival and LPFS. One-year LPFS for patients with surgery was 80% and 44% without surgery. Within the 15.4-month follow-up, no grade 3+ toxicity from SABR was observed. No significant quality of life change was observed before and after ICT, SABR, or surgery for BR or LA patients. Conclusions This is the first prospective phase 2 study to investigate the feasibility and efficacy of a 12-week gemcitabine/capecitabine ICT followed by SABR for BR or LA PDAC. The results suggest excellent tolerability, high R0 resection rates, and acceptable posttreatment complications.

Purpose/Objective(s) There is increasing interest in using stereotactic body radiation therapy (SBRT) to areas of oligoprogressive metastatic disease (OPD) to allow for the prolongation of a patient's current systemic therapy regimen or delay the need to start a new regimen. The main objective of our study was to investigate the impact of SBRT on survival and the incidence of systemic therapy treatment switch in this group of patients. Materials/Methods A retrospective institutional review of patients treated with SBRT for OPD was performed. Patients were included if they received SBRT for 1-3 discrete progressing metastases, using a dose of at least 5 Gy per fraction. The study aimed to calculate progression free survival (PFS), overall survival (OS), local control (LC) and incidence of treatment switch (TS). PFS and OS were calculated using Kaplan-Meier methodology, while LC and TS were determined using cumulative incidence to account for competing risks of death without progression. Results Eighty-one patients with a total of 118 lesions were treated with SBRT from July 2014-November 2020. Median SBRT dose was 40 (18-60) Gy in 5 (2-8) fractions. Patients with kidney, lung, and breast cancer constituted the majority of patients. The last systemic therapy prior to OPD was tyrosine kinase inhibitor (TKI) (30.9%), chemotherapy (29.6%), immunotherapy (12.3%), chemo/VEGF (8.6%), hormonal (6.2%), CDK 4/6 (2.5%). Ten percent were on surveillance for indolent metastatic disease. Median follow-up post SBRT was 14 months. Median OS and PFS were 25.1 (95% CI 11.2 – 39.1) months and 7.8 (95% CI 4.6-10.9) months, respectively. The cumulative incidence of local progression of treated lesions was 5% at 1 year and 7.3% at 2 years. Sixty patients progressed after SBRT (mostly distant failure) and 17 underwent additional SBRT for further OPD. Thirty-eight patients (47%) ultimately changed systemic therapy following SBRT; the cumulative incidence of TS was 28.5% at 6 months, 37.4% at 1 year, and 43.9% at 2 years. Overall, after SBRT there were 16 acute and 2 late, grade 3 toxicities and no grade 4 or 5 acute or late toxicity observed. Conclusion SBRT effectively controls locally progressing lesions but distant progression still occurs frequently. However, a sizeable number of patients can be salvaged by further SBRT or have minimally progressing disease that may not warrant an immediate initiation or switch in systemic therapy. This is illustrated by the fact that over half the patients did not require a TS at two years. Further prospective studies are warranted to validate the benefit of integrating SBRT with systemic therapy strategies for patients with OPD.

Introduction Limited data establish the efficacy and safety of SBRT in the abdominopelvic (AP) space, where SBRT delivery is challenging due to the proximity of radiosensitive luminal gastrointestinal (GI) organs. The aim of this study was to assess clinical outcomes in patients with AP OM treated with SBRT. Methods Eligible patients were those with OM (defined as metastases in ≤3 total sites) in the AP space (excluding liver) treated with SBRT. Descriptive statistics and Kaplan-Meier estimates of (LC), progression-free survival (PFS), overall survival (OS) and chemotherapy-free survival (CFS) were performed. Results Fifty-one patients with 58 AP OM received SBRT between 2011 and 2015. Median follow-up was 21.9 months. All SBRT treatments were delivered in 5 fractions with a median dose of 35 Gy (25-40 Gy). Progression post-SBRT occurred in 38/51 patients (75%), with a median PFS of 4.9 months (95% CI: 2.5-7.5), and 2-year PFS of 29%. Rates of 2-and 4-year LC were 74% and 69%, respectively. Median OS was 42.6 months (95% CI: 31-55). Oligometastatic progression occurred in 21/38 patients, and of those, 48% (10/21) received further SBRT. Resulting 2- and 4-year CFS were 47% and 37%, respectively (median 15.1 months). Nineteen patients (37%) experienced a grade 1 or 2 acute toxicity. One grade 3 (acute) toxicity was observed. No grade 4 or 5 toxicities were detected. Conclusions SBRT to AP OM was associated with sustained LC, excellent OS and minimal toxicity. The use of SBRT allowed for prolonged CFS and the salvage of limited-burden distant failures.

Standard therapy for high-risk (HR) prostate cancer (PrCa) involves androgen deprivation therapy (ADT) and pelvic conventional fractionation (CF) external beam radiotherapy (EBRT) followed by boost CF-EBRT treatment to prostate for a total of 78 to 80 Gy in 39 to 40 fractions. This is a long and inconvenient treatment for patients. Brachytherapy boost treatment studies indicate that escalation of biological dose of radiotherapy (RT) can improve outcomes in HR-PrCa. However, brachytherapy is an invasive treatment associated with increased toxicity and requires specialized resources. Stereotactic body radiotherapy (SBRT) is a promising, non-invasive alternative to brachytherapy. However, its impact on patient quality of life (QoL) and RT-associated toxicity has not been investigated in a randomized setting. In this study, we investigate SBRT as a boost treatment, following pelvic CF-EBRT, in patients with HR-PrCa treated with ADT. One hundred patients with locally advanced PrCa will be randomized to receive daily CF-EBRT of 45 to 46 Gy in 23 to 25 fractions followed by either daily CF-EBRT of 32 to 33 Gy in 15 to 16 fractions (control arm) or SBRT boost treatment of 19.5 to 21 Gy in 3 fractions (1 fraction per week) (experimental arm). The primary objective of the PBS trial is early bowel and urinary QoL (expanded prostate index composite [EPIC], up to 6 months after RT). This phase II randomized study (PBS) provides an appropriate setting to investigate effectively the impact of SBRT boost on QoL and toxicity in patients with HR-PrCa, before this modality can be compared against the current standard of care in larger phase III protocols.

Background/introduction Early reports of stereotactic body radiation therapy (SBRT) for pancreatic ductal adenocarcinoma (PDAC) used single fraction, but eventually shifted to multifraction regimens. We conducted a single institution review of our patients treated with single- or multifraction SBRT to determine whether any outcome differences existed. Methods and materials Patients treated with SBRT in any setting for PDAC at our facility were included, from 2004 to 2014. Overall survival (OS), local control (LC), regional control (RC), distant metastasis (DM), and late grade 3 or greater radiation toxicities from the time of SBRT were calculated using Kaplan–Meier estimation to either the date of last follow-up/death or local/regional/distant failure. Results We identified 289 patients (291 lesions) with pathologically confirmed PDAC. Median age was 69 (range, 33–90) years. Median gross tumor volume was 12.3 (8.6–21.3) cm3 and planning target volume 17.9 (12–27) cm3. Single fraction was used in 90 (30.9%) and multifraction in 201 (69.1%) lesions. At a median follow-up of 17.3 months (IQR 10.1–29.3 months), the median survival for the entire cohort 17.8 months with a 2-year OS of 35.3%. Univariate analysis showed multifraction schemes to have a higher 2-year OS 30.5% vs. 37.5% (p = 0.019), it did not hold significance on MVA. Multifractionation schemes were found to have a higher LC on MVA (HR = 0.53, 95% CI, 0.33–0.85, p = 0.009). At 2 years, late grade 3+ toxicity was 2.5%. Post-SBRT CA19-9 was found on MVA to be a prognostic factor for OS (HR = 1.01, 95% CI, 1.01–1.01, p = 0.009), RC (HR = 1.01, 95% CI 1.01–1.01, p = 0.02), and DM (HR = 1.01, 95% CI, 1.01–1.01, p = 0.001). Conclusion Our single institution retrospective review is the largest to date comparing single and multifraction SBRT and the first to show multifraction regimen SBRT to have a higher LC than single fractionation. Additionally, we show low rates of severe late toxicity with SBRT.

Background: Glioblastoma multiforme (GBM) carries a poor prognosis with high recurrence rates. Salvage stereotactic radiosurgery (SRS) may be an effective treatment option. Methods: We retrospectively reviewed 34 patients (41 lesions) treated with salvage SRS for recurrent GBM between 2004 and 2012. Initial surgical treatments were gross total resection (58%), subtotal resection (STR) (24%), and biopsy (18%). All patients were treated with prior radiation therapy. Recurrent disease was treated with salvage SRS with a median dose and fractions of 23.4 Gy (range, 12–30) and 3 (range, 1–3), respectively. Cox proportional hazards regression was conducted to establish predictive factors (P ≤ 0.05) Results: Median follow-up from salvage SRS was 10.8 months (interquartile range [IQR], 7.0–15.6). The median time from initial radiation therapy to salvage SRS was 13.7 months (IQR, 2.9–25.0). The 6- and 12-month overall survival from salvage SRS were 84.9% and 42.5%, respectively. On univariate analysis, STR was associated with inferior survival from salvage SRS (P ≤ 0.05). The 6- and 12-month local control (LC) estimates were 63.1% and 16.4%, respectively. On univariate analysis, higher biological effective dose and prior temozolomide were associated with superior LC. Concerning toxicity, there were 4 (12%) grade 2 and 1 (3%) grade 3 adverse events within this patient series. No grade 4 or grade 5 toxicities were observed. Conclusion: Our outcomes suggest that SRS is a feasible treatment option with acceptable salvage survival rates, given the poor prognosis of this disease.

Stereotactic ablative radiotherapy (SABR) with concomitant cetuximab is an effective treatment option for previously irradiated, locally recurrent squamous cell carcinoma of the head and neck. Its local control and overall survival are similar to those of other available treatment options. Each retreatment depends heavily on the prior treatment and every patient is a special case. Based on the experience of our institution and previously published studies, for patients who receive concomitant cetuximab with a median prior radiation therapy dose of 70Gy, we recommend a total dose of 40-44Gy delivered in 5 fractions on alternating days over 1-2 weeks. However, Grade 2 or 3 toxicities are not uncommon. Therefore, in this review, we also report a pilot study that applies a normal tissue complication probability dose-response model to estimate the probability of toxicities in locally recurrent squamous cell carcinoma of the head and neck reirradiated with SABR. Although this dose-response model includes concurrent targeted therapy and no comparable model yet exists for SABR without it, complication rates without concurrent biological therapy or chemotherapy should be no higher than those described here.

BACKGROUND: Due to the poor prognosis of glioblastoma multiforme (GBM) and high recurrence rates, salvage stereotactic radiosurgery (SRS) may be an effective treatment option given its ability to deliver a high dose of radiation within a small volume. Here we investigate the efficacy of salvage SRS for recurrent GBM. METHODS: We retrospectively reviewed 34 patients (41 lesions) treated with salvage SRS for recurrent GBM between 2004-2012. Initial surgical treatments were as follows: gross total resection (58%), subtotal resection (24%), and biopsy (18%). All patients were treated with prior radiotherapy. Recurrent disease was treated with salvage SRS with a median dose of 23.4 Gy (range 12-30) and delivered in a median fraction number of 3 (range 1-3). Cox proportional hazards regression was conducted to establish prognostic factors (p < 0.05). RESULTS: Median follow-up from salvage SRS was 10.8 months (IQR 7.0-15.6). The median time from initial radiotherapy to salvage SRS was 13.7 months (IQR 2.9-25.0). The 6- and 12-month overall survival from salvage SRS were 84.9% and 42.5%, respectively. Upon univariate analysis, subtotal resection (HR = 2.8, p = 0.021) was associated with inferior survival from salvage SRS. The 6- and 12-month local control estimates were 63.1%, and 16.4%, respectively. Using univariate analysis, higher BED (HR = 0.99, p = 0.018) was associated with superior local control. Neither time to recurrence or recurrent tumor volume were associated with local failure. Concerning toxicity, there were 4 (12%) grade 2 and 1 (3%) grade 3 radiation-related toxicities. No grade 4 or 5 toxicities were observed. CONCLUSIONS: Salvage radiosurgery provides an intriguing treatment option for recurrent GBM with minimal toxicity. Our outcomes suggest this is a feasible treatment option with acceptable salvage survival rates given the poor prognosis this diagnosis carries.

The aim of this study is to provide a practical approach to the planning technique and evaluation of plan quality for the multi-lesion, single-isocenter stereotactic ablative radiotherapy (SABR) of the lung. Eleven patients with two or more lung lesions underwent single-isocenter volumetric-modulated arc therapy (VMAT) radiosurgery or IMRS. All plans were normalized to the target maximum dose. For each plan, all targets were treated to the same dose. Plan conformity and dose gradient were maximized with dose-control tuning structures surrounding targets. For comparison, multi-isocenter plans were retrospectively created for four patients. Conformity index (CI), homogeneity index (HI), gradient index (GI), and gradient distance (GD) were calculated for each plan. V5, V10, and V20 of the lung and organs at risk (OARs) were collected. Treatment time and total monitor units (MUs) were also recorded. One patient had four lesions and the remainder had two lesions. Six patients received VMAT and five patients received intensity-modulated radiosurgery (IMRS). For those treated with VMAT, two patients received 3-arc VMAT and four received 2-arc VMAT. For those treated with IMRS, two patients were treated with 10 and 11 beams, respectively, and the rest received 12 beams. Prescription doses ranged from 30 to 54 Gy in three to five fractions. The median prescribed isodose line was 84% (range: 80-86%). The median maximum dose was 57.1 Gy (range: 35.7-65.1 Gy). The mean combined PTV was 49.57 cm(3) (range: 14.90-87.38 cm(3)). For single-isocenter plans, the median CI was 1.15 (range: 0.97-1.53). The median HI was 1.19 (range: 1.16-1.28). The median GI was 4.60 (range: 4.16-7.37). The median maximum radiation dose (Dmax) to total lung was 55.6 Gy (range: 35.7-62.0 Gy). The median mean radiation dose to the lung (Dmean) was 4.2 Gy (range: 1.1-9.3 Gy). The median lung V5 was 18.7% (range: 3.8-41.3%). There was no significant difference in CI, HI, GI, GD, V5, V10, and V20 (lung, heart, trachea, esophagus, and spinal cord) between single-isocenter and multi-isocenter plans. This multi-lesion, single-isocenter lung SABR planning technique demonstrated excellent plan quality and clinical efficiency and is recommended for radiosurgical treatment of two or more lung targets for well-suited patients.

Background Despite improved staging and surgical techniques, the rate of incomplete resection (R1) of non–small-cell lung cancer (NSCLC) has not significantly decreased. Patients with R1 resection have worse survival compared with those with complete resection (R0). Stereotactic body radiotherapy (SBRT) is a rapid and convenient radiotherapy treatment that delivers high-dose radiotherapy to tumors with high precision while sparing normal organs. Although its efficacy in treating small lung tumors is documented, its use as neoadjuvant therapy for locally advanced (LA) NSCLC has not been examined. We hypothesized that a short course of preoperative SBRT is feasible and can be delivered safely as a neoadjuvant therapy in patients at risk for incomplete resection. Methods In this phase I study, 20 patients with cT3 to 4, N0 to 1, M0 NSCLC at risk for incomplete resection will be treated with neoadjuvant SBRT followed by surgery and adjuvant chemotherapy. Four groups of 5 patients will be treated with escalating doses (35, 40, 45, and 50 Gy) in 10 daily fractions. The primary outcome is feasibility (ie, the ability to complete SBRT and surgery as planned; within 7 weeks). Secondary outcomes include acute and late adverse events; R0, R1, and R2 rates; and secondary surrogates of feasibility and safety. Relevance This study is an important first step in introducing a new therapeutic modality to patients with LA NSCLC that could improve surgical outcomes in the future. If neoadjuvant SBRT is found to be feasible and safe for LA NSCLC, its effect in achieving R0 resection could be investigated in randomized trials.

Intravascular lymphoma (IVL) is a rare form of non-Hodgkin lymphoma characterized by proliferation of malignant lymphoid cells limited to the lumen of small vessels. Clinical manifestations are nonspecific and result from vascular obliteration and hypoxia. The disease affects primarily the skin and central nervous system, often associated with rapid systemic dissemination and aggressive clinical course if appropriate therapy is not initiated early. Involvement of the lungs, kidneys, adrenal glands, and prostate may occur. Primary pulmonary IVL is exceedingly rare. We describe a case of primary pulmonary IVL in an HIV-positive man presenting with nonspecific constitutional symptoms. High-resolution computed tomography demonstrated centrilobular nodules with ground-glass attenuation and peribronchial ground-glass opacities. The diagnosis was confirmed by thoracoscopic biopsy and histologic findings consisted of accumulation of malignant lymphocytes within alveolar capillaries, pulmonary veins, and peribronchial arterioles. Immunohistochemistry confirmed positivity for CD20, a marker for B lymphocytes. Combined systemic chemotherapy including rituximab was started and resulted in significant clinical and radiologic improvement with long-term disease-free survival.

Objectives: Locoregional recurrence rate in squamous cell carcinoma of head and neck (SCCHN) following chemoradiation is high. The objective of this study is to determine dosevolume relationship to toxicities of normal tissues in previously-irradiated, locally-recurrent SCCHN (rSCCHN) treated with stereotactic ablative radiotherapy (SABR). Methods: A retrospective review of 20 patients with previously-irradiated, locally rSCCHN from 2008-2011 was conducted. Tumors with a GTV less than 25 cm3 received 8.0 Gy per fraction for 5 fractions (total dose of 40 Gy); tumors with a GTV more than 25 cm3 received 8.8 Gy per fraction for 5 fractions (total dose of 44 Gy). Toxicity was graded based on Common Terminology Criteria for Adverse Events (CTCAE) v3.0. Physical dose was converted into 2Gyper-fraction equivalent dose (EQD2) to correct for different fractionation schemes and allow for summation of SABR and previous IMRT plans. Logistic regression of composite dose volume histogram (DVH) data was performed in the DVH Evaluator software. Maximum likelihood parameter fitting was applied to solve TD50 (v) and normalized slope v50 of the exponential form of the logistic dose response model. Results: Median age was 64 y/o (range: 45-87 y/o) with 14 (70%) males and 6 (30%) females. Thirteen (65%) patients received surgery and 12 (60%) patients received chemotherapy. The median previous radiation dose was 70 Gy (range: 63-118.2 Gy). The median time from prior radiation therapy to SABR was 12.5 months (range: 3-39 months). The median maximum SABR dose was 50 Gy (range: 47.3-55 Gy). The median prescribed SABR EQD2 was 88 Gy (range: 88103.8 Gy) for a/b =3 Gy and was 60 Gy (range: 60-68.9 Gy) for a/b = 10 Gy, respectively. The median tumor volume was 27.3 cc (range: 4.4-75.7 cc). No Grade 4 or greater toxicity was observed. 1 (5%) patient had Grade 3 mucositis. 5 (25%) patients had Grade 2 mucositis and 6 (30%) patients had Grade 1 mucositis. Grade 2-3 mucositis correlated with median composite EQD2 to oral mucosa (TD50 (v) =190.8 Gy, v50 =0.3876). Outcomes were better correlated with median composite EQD2 to structures than to doses for small volumes, possibly due to tight Open Access Abstract