Latifa Yeung

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

PURPOSE This 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). MATERIALS AND METHODS Twenty-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. RESULTS There 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). CONCLUSIONS While 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.

PURPOSE To 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. METHODS AND MATERIALS Peripherally 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. RESULTS A 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. CONCLUSIONS Accelerated 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.

Lung stereotactic body radiation therapy (SBRT) delivered over 4 or 11 days: A comparison of acute toxicity and quality of life

PURPOSE The optimal duration over which lung SBRT should be delivered is unknown. We conducted a randomized pilot study in patients treated with four fractions of lung SBRT delivered over 4 or over 11 days. METHODS Patients with a peripheral solitary lung tumor (NSCLC or pulmonary metastasis) ≤ 5 cm were eligible. For NSCLC lung tumors ≤ 3 cm, a dose of 48 Gy in 4 fractions was used, otherwise 52 Gy in 4 fractions was delivered. Patients were randomized to receive treatment over 4 consecutive days or over 11 days. The primary end-point was acute grade ≥ 2 toxicity. Secondary end-points included quality of life (QOL) assessed using the EORTC QLQ-C30 and QLQ-LC13 questionnaires. RESULTS Fifty four patients were enrolled. More patients in the 11 day group had respiratory symptoms at baseline. 55.6% patients treated over 4 days and 33.3% of patients treated over 11 days experienced acute grade ≥ 2 toxicity (p=0.085). Dyspnea, fatigue and coughing domains were worse in the 11 day group at baseline. At 1 and 4 months, more patients in the 4 day group experienced a clinically meaningful worsening in the dyspnea QOL domain compared to the 11 day group (44.5% vs 15.4%, p=0.02; 38.5% vs 12.0%, p=0.03, respectively). However, raw QOL scores were not different at these time-points between treatment groups. CONCLUSIONS Grade 2 or higher acute toxicity was more common in the 4 day group, approaching statistical significance. More patients treated on 4 consecutive days reported a clinically meaningful increase in dyspnea, although interpretation of these results is challenging due to baseline imbalance between treatment groups. Larger studies are required to validate these results.

Predictors of Chest Wall Toxicity after Lung Stereotactic Ablative Radiotherapy

AIMS To determine the incidence and predictive factors of rib fracture and chest wall pain after lung stereotactic ablative radiotherapy (SABR). MATERIALS AND METHODS Patients were treated with lung SABR of 48-60 Gy in four to five fractions. The treatment plan and follow-up computed tomography scans of 289 tumours in 239 patients were reviewed. Dose-volume histogram (DVH) metrics and clinical factors were evaluated as potential predictors of chest wall toxicity. RESULTS The median follow-up was 21.0 months (range 6.2-52.1). Seventeen per cent (50/289) developed a rib fracture, 44% (22/50) were symptomatic; the median time to fracture was 16.4 months. On univariate analysis, female gender, osteoporosis, tumours adjacent (within 5 mm) to the chest wall and all of the chest wall DVH metrics predicted for rib fracture, but only tumour location adjacent to the chest wall remained significant on the multivariate model (P < 0.01). The 2 year fracture-free probability for those adjacent to the chest wall was 65.6%. Among those tumours adjacent to the chest wall, only osteoporosis (P = 0.02) predicted for fracture, whereas none of the chest wall DVH metrics were predictive. Eight per cent (24/289) experienced chest wall pain without fracture. CONCLUSIONS None of the chest wall DVH metrics independently predicted for SABR-induced rib fracture when tumour location is taken into account. Patients with tumours adjacent (within 5 mm) to the chest wall are at greater risk of rib fracture after lung SABR, and among these, an additional risk was observed in osteoporotic patients.