Ian Poon

A comparison of two immobilization systems for stereotactic body radiation therapy of lung tumors

PURPOSEnThis study aims to compare the efficacy, efficiency and comfort level of two immobilization systems commonly used in lung stereotactic body radiation therapy (SBRT): the Bodyfix and the abdominal compression plate (ACP).nnnMATERIALS AND METHODSnTwenty-four patients undergoing SBRT for medically inoperable stage I lung cancer or pulmonary metastases were entered on this prospective randomized study. All underwent 4DCT simulation with free breathing, the Bodyfix, and the ACP to assess respiratory tumor motion. After CT simulation, patients were randomly assigned to immobilization with either the Bodyfix or the ACP for the actual SBRT treatment. Cone beam CTs (CBCTs) were acquired before and after each treatment to assess intrafraction tumor motion. Setup time and patient comfort were recorded.nnnRESULTSnThere were 16 upper lobe, two middle lobe and seven lower-lobe lesions. Both the Bodyfix and the ACP significantly reduced the superior-inferior (SI) and overall respiratory tumor motion compared to free breathing (4.6 and 4.0 vs 5.3mm; 5.3 and 4.7 vs 6.1mm, respectively, p<0.05). The ACP further reduced the SI and overall respiratory tumor motion compared to the Bodyfix (p<0.05). The mean overall intrafraction tumor motion was 2.3mm with the Bodyfix and 2.0mm with the ACP (p>0.05). The ACP was faster to set up and rated more comfortable by patients than the Bodyfix (p<0.05).nnnCONCLUSIONSnWhile there is no significant difference between the Bodyfix and ACP in reducing intrafraction tumor motion, the ACP is more comfortable, faster to set up, and superior to the Bodyfix in reducing SI and overall respiratory tumor motion.

Accelerated hypofractionated radiotherapy for early-stage non-small-cell lung cancer: long-term results.

PURPOSEnTo retrospectively review the results of a single-institution series of accelerated hypofractionated radiotherapy for early-stage non-small-cell lung cancer (NSCLC) in patients who are medically inoperable or who refuse surgery.nnnMETHODS AND MATERIALSnPeripherally located T1 to T3 N0 M0 tumors were treated with 48 to 60 Gy in 12 to 15 fractions between 1996 and 2007. No elective nodal irradiation was delivered. Patient, tumor, and treatment information was abstracted from the medical records.nnnRESULTSnA total of 124 tumors were treated in 118 patients (56 male and 62 female). Median age at diagnosis was 76.3 years (range, 49-90 years). In all, 113 patients (95.8%) were not surgical candidates because of medical comorbidities. The 2- and 5-year overall survival (OS) rates were 51.0% and 23.3%, respectively, and the 2- and 5-year cause-specific survival (CSS) rates were 67.6% and 59.8%, respectively. The 2- and 5-year actuarial local control (LC) rates were 76.2% and 70.1%, respectively. Univariate analysis revealed that tumor size less than 3 cm compared with greater than 3 cm resulted in significantly improved OS (40.0% vs. 5.0% at 5 years; p = 0.0002), CSS (69.7% vs. 45.1% at 5 years; p = 0.0461), and a trend toward better LC (82.5% vs. 66.9% at 2 years, 76.6% vs. 60.8% at 5 years; p = 0.0685). Treatment was well tolerated and there were no treatment delays because of acute toxicity.nnnCONCLUSIONSnAccelerated hypofractionated radiotherapy with 48 to 60 Gy using fractions of 4 Gy per day provides very good results for small tumors in medically inoperable patients with early-stage NSCLC.

The value of periodic follow-up in the detection of recurrences after radical treatment in locally advanced head and neck cancer.

AIMSnTo determine the value of routine follow-up in detecting and salvaging recurrence after radical treatment of locally advanced head and neck squamous cell carcinoma and to identify clinical or pathological prognostic factors that predicted for survival.nnnMATERIALS AND METHODSnA retrospective medical chart review was conducted at the Odette Cancer Centre between January 2000 and May 2006. Two hundred and twenty-three patients with advanced (stage III or IV) squamous cell carcinoma of the head and neck who were treated with curative intent were reviewed. Recurrences were divided into local, regional or distant recurrences. The detection method for each recurrence was categorised as self or physician detected. A self-detected recurrence arose from symptoms that led to investigations that confirmed a recurrence (even if initiated at the time of a routine visit), whereas a physician-detected recurrence was found during the routine follow-up examination and was asymptomatic.nnnRESULTSnThere was no evidence to suggest a significant improvement in disease-free or overall survival in the physician-detected versus patient-detected groups. Regional and distant recurrences were only detected by physicians in one-fifth of cases and, overall, patients self-detected their own recurrence in two-thirds of the cases that experienced disease progression within the sample. Of the 12 clinical/pathological variables considered, only the response to treatment and perineural invasion were associated with survival.nnnCONCLUSIONSnCurrent surveillance methods do not appear to improve cancer control in the stage III/IV head and neck squamous cell carcinoma population. However, technological advances and biomarker development may lead to surveillance technique enhancements. Also, post-treatment follow-up remains important for the evaluation of treatment results, emotional support and management of late complications. Among the clinical and pathological factors considered, only the treatment response and perineural invasion predicted survival.

Tumor Response After Stereotactic Body Radiation Therapy to Nonspine Bone Metastases: An Evaluation of Response Criteria

PURPOSEnTo evaluate the applicability of the Response Evaluation Criteria in Solid Tumors (RECIST 1.1) and University of Texas MD Anderson (MDA) Cancer Center criteria in the setting of stereotactic body radiation therapy (SBRT) to nonspine bone metastases.nnnMETHODSnPatients who were treated with SBRT to nonspine bone metastases were identified by retrospective chart review. An independent musculoskeletal radiologist evaluated response to treatment using computed tomography (CT) scans.nnnRESULTSnThirty-three patients were treated to 42 nonspine bone metastases. The most common primary cancer cites were renal cell carcinoma (RCC) (33.3%), lung (24.2%), and prostate (18.2%). Bone metastases were either mainly lytic (57.1%), mainly sclerotic (28.6%), or mixed (14.3%). When lytic and sclerotic lesions were evaluated according to RECIST 1.1, local control (LC) was 83%, 85%, 88%, and 80% for those with CT imaging between months 1 to 3, 4 to 6, 7 to 9, and 10 to 12, respectively. When evaluated by the MDA criteria by density, LC within each time period was slightly greater. Overall LC decreased considerably when evaluated by MDA in terms of size.nnnCONCLUSIONSnConsensus definitions of response are required as they have implications on clinical trials and disease management. Without consistent response criteria, outcomes from clinical trials cannot be compared and treatment efficacy remains undetermined.

Magnetic resonance-guided high-intensity focused ultrasound combined with radiotherapy for palliation of head and neck cancer-a pilot study.

BackgroundRadiotherapy is a critical component of the multidisciplinary management of cancers of the head and neck. It may comprise the primary curative treatment modality or is used in an adjuvant setting to improve local control and survival by preventing seeding and reseeding of distant metastases from persistent reservoirs of locoregional disease. Although considerable advances have been made recently in the fields of radiotherapy, systemic treatment and surgery for head and neck tumours, locoregional recurrence rates remain high and treatment side effects may have severe impact on patients’ quality of life.Magnetic resonance-guided high-intensity focused ultrasound (MRg-HIFU) is a novel technique in the treatment of cancer that has the potential to improve tumour cure rates and decrease treatment-related toxicity. Clinical applications of HIFU are being used increasingly for the treatment of several tumour sites, for example uterine leiomyomas and prostate cancer.Methods/DesignThe pilot study presented here is an initial step toward utilizing MRg-HIFU for head and neck cancer treatment. The rationale for novel treatment options in head and neck cancer is reviewed as well as emerging evidence that support the increasing clinical utilization of MRg-HIFU.DiscussionThis pilot study aims to assess safety, toxicity and feasibility of MRg-HIFU treatments to the head and neck region and to evaluate changes caused by MRg-HIFU within the treated tumour regions based on post-treatment MRI.

Computed Tomography Evaluation of Density Following Stereotactic Body Radiation Therapy of Nonspine Bone Metastases.

Introduction: Stereotactic body radiation therapy allows for the precise delivery of high-dose radiation to disease sites and is becoming increasingly used to treat nonspine bone metastases. Previous studies have shown that remineralization of lytic bone metastases follows after conventional radiotherapy. The objective of this study was to investigate changes in bone density in nonspine bone metastases following stereotactic body radiation therapy. Methods: A retrospective review was conducted for all patients treated with stereotactic body radiation therapy to nonspine bone metastases between May 2011 and April 2014. A minimum of 1 pretreatment and 1 posttreatment computed tomography scan was required. An independent musculoskeletal radiologist contoured the lesions on the most representative computed tomography slices. Density was measured in Hounsfield units and analyzed using pretreatment and posttreatment ratios. Results: Forty sites were treated (55% lytic, 30% sclerotic, and 15% mixed). The median follow-up duration was 7 months. Lytic osseous metastases from renal cell carcinoma progressed during initial follow-up imaging and then returned to baseline. Of 9 lytic lesions not from renal cell carcinoma, 6 showed an immediate increase in density and 2 remained stable. Six of 7 sclerotic lesions from prostate cancer showed decreased density throughout all follow-ups. Conclusion: Stereotactic body radiation therapy is efficacious in the remineralization of lytic and demineralization of sclerotic nonspine bone metastases.

Radiomics analysis at PET/CT contributes to prognosis of recurrence and survival in lung cancer treated with stereotactic body radiotherapy

We sought to quantify contribution of radiomics and SUVmax at PET/CT to predict clinical outcome in lung cancer patients treated with stereotactic body radiotherapy (SBRT). 150 patients with 172 lung cancers, who underwent SBRT were retrospectively included. Radiomics were applied on PET/CT. Principal components (PC) for 42 CT and PET-derived features were examined to determine which ones accounted for most of variability. Survival analysis quantified ability of radiomics and SUVmax to predict outcome. PCs including homogeneity, size, maximum intensity, mean and median gray level, standard deviation, entropy, kurtosis, skewness, morphology and asymmetry were included in prediction models for regional control (RC) [PC4-HR:0.38, pu2009=u20090.02], distant control (DC) [PC4-HR:0.51, pu2009=u20090.02 and PC1-HR:1.12, pu2009=u20090.01], recurrence free probability (RFP) [PC1-HR:1.08, pu2009=u20090.04], disease specific survival (DSS) [PC2-HR:1.34, pu2009=u20090.03 and PC3-HR:0.64, pu2009=u20090.02] and overall survival (OS) [PC4-HR:0.45, pu2009=u20090.004 and PC3-HR:0.74, pu2009=u20090.02]. In combined analysis with SUVmax, PC1 lost predictive ability over SUVmax for RFP [HR:1.1, pu2009=u20090.04] and DC [HR:1.13, pu2009=u20090.002], while PC4 remained predictive of DC independent of SUVmax [HR:0.5, pu2009=u20090.02]. Radiomics remained the only predictors of OS, DSS and RC. Neither SUVmax nor radiomics predicted recurrence free survival. Radiomics on PET/CT provided complementary information for prediction of control and survival in SBRT-treated lung cancer patients.

Impact of Magnetic Resonance Imaging on Gross Tumor Volume Delineation in Non-spine Bony Metastasis Treated With Stereotactic Body Radiation Therapy

PURPOSEnThis study investigates the inter-observer variability of contouring non-spine bone metastases using the planning CT alone vs. the addition of MRI T1 and T2 imaging sequences.nnnMETHODS AND MATERIALSn10 cases of non-spine bone metastases treated with SBRT at our institution were selected. The gross tumor volume (GTV) for each case was delineated by six SBRT radiation oncologists (RO) and one diagnostic radiologist (DR) on the treatment planning CT. After a minimum of three months, each case was re-contoured on the CT fused with a MRI T1 sequence followed by a MRI T2 sequence. STAPLE consensus contours were created from the RO volumes and inter-observer variability was measured using both κ agreement and the Dice coefficient (DSC).nnnRESULTSnIn total, 180 RO contours were analyzed within three datasets (CT, CT + MRI T1 and CT + MRI T1 + MRI T2). The mean GTV was 16.95 cm3 (range, 0.12-269.6 cm3). The RO κ agreement was 0.6129 based on CT alone, and significantly increased to 0.7045 in the CT + MRI T1 (P = .042) dataset and 0.7017 in the CT + MRI T1 + MRI T2 dataset (P = .048). The mean DSC in the CT alone dataset was 0.7047, and significantly increased to 0.7628 in the CT + MRI T1 dataset (P < .001) and 0.7544 in the CT + MRI T1 + MRI T2 dataset (P = .001). There were no statistical differences in RO κ agreement (P = .948) or mean DSC (P = .573) when comparing the CT + MRI T1 and CT + MRI T1 + MRI T2 datasets. The DSC agreement between DR and RO volumes was lowest (0.6887) in the CT alone dataset and significantly increased to 0.7398 in the CT + MRI T1 dataset (P = .003) and 0.7342 in the CT + MRI T1 + MRI T2 dataset (P = .008).nnnCONCLUSIONSnThe fusion of MRI T1 images to CT significantly reduced inter-observer variability amongst ROs in delineating non-spine bone metastases, and improved agreement between GTVs delineated by the RO to the DR.

Contents Vol. 78, 2016

R.L. Alford, Houston, Tex. M. Anniko, Uppsala Y.A. Bayazit, Ankara H.H. Birdsall, Houston, Tex. P.J. Bradley, Nottingham J. Califano, Boston, Mass. P.F. Castellanos, Birmingham, Ala. C. Cernea, São Paulo F.-L. Chi, Shanghai A. Chiu, Tucson, Ariz. N. Cohen, Philadelphia, Pa. M.D. Eisen, Hartford, Conn. L.M. Elden, Philadelphia, Pa. E. Ferekidis, Athens A. Ferlito, Udine R.L. Ferris, Pittsburgh, Pa. L.L. Gleich, Cincinnati, Ohio D.-M. Han, Beijing J.P. Harris, San Diego, Calif. R. Häusler, Bern I. Hochmair, Innsbruck K. Hörmann, Mannheim Journal for Oto-Rhino-Laryngology, Head and Neck Sugery