J. P. Bissonnette

Stereotactic Body Radiotherapy for Medically Inoperable Lung Cancer: Prospective, Single-Center Study of 108 Consecutive Patients

PURPOSEnTo present the results of stereotactic body radiotherapy (SBRT) for medically inoperable patients with Stage I non-small-cell lung cancer (NSCLC) and contrast outcomes in patients with and without a pathologic diagnosis.nnnMETHODS AND MATERIALSnBetween December 2004 and October 2008, 108 patients (114 tumors) underwent treatment according to the prospective research ethics board-approved SBRT protocols at our cancer center. Of the 108 patients, 88 (81.5%) had undergone pretreatment whole-body [18F]-fluorodeoxyglucose positron emission tomography/computed tomography. A pathologic diagnosis was unavailable for 33 (28.9%) of the 114 lesions. The SBRT schedules included 48 Gy in 4 fractions or 54-60 Gy in 3 fractions for peripheral lesions and 50-60 Gy in 8-10 fractions for central lesions. Toxicity and radiologic response were assessed at the 3-6-month follow-up visits using conventional criteria.nnnRESULTSnThe mean tumor diameter was 2.4-cm (range, 0.9-5.7). The median follow-up was 19.1 months (range, 1-55.7). The estimated local control rate at 1 and 4 years was 92% (95% confidence interval [CI], 86-97%) and 89% (95% CI, 81-96%). The cause-specific survival rate at 1 and 4 years was 92% (95% CI, 87-98%) and 77% (95% CI, 64-89%), respectively. No statistically significant difference was found in the local, regional, and distant control between patients with and without pathologically confirmed NSCLC. The most common acute toxicity was Grade 1 or 2 fatigue (53 of 108 patients). No toxicities of Grade 4 or greater were identified.nnnCONCLUSIONSnLung SBRT for early-stage NSCLC resulted in excellent local control and cause-specific survival with minimal toxicity. The disease-specific outcomes were comparable for patients with and without a pathologic diagnosis. SBRT can be considered an option for selected patients with proven or presumed early-stage NSCLC.

Chest Wall Pain and Rib Fracture after Stereotactic Radiotherapy for Peripheral Non-small Cell Lung Cancer

Stereotactic body radiotherapy is an emerging treatment option for peripheral non-small cell lung cancer in medically inoperable patients. With high dose per fraction radiotherapy, late side effects are of possible concern. In our initial cohort of 42 patients treated with 54 to 60 Gy in three fractions, nine patients have rib fracture. The median dose to rib fracture sites was 46 to 50 Gy, depending on the method of dose calculation. We describe a typical case of poststereotactic radiotherapy rib fracture and present dosimetric analysis of patients with rib fracture.

Tumor Regression and Positional Changes in Non-small Cell Lung Cancer During Radical Radiotherapy

Introduction: We have used respiratory-correlated cone beam computed tomography (rcCBCT) imaging to study the volumetric and positional changes that occur throughout the course of radical radiotherapy in non-small cell lung cancer (NSCLC). Methods: Tumor volumes and centers of mass were recorded and analyzed on weekly serial rcCBCT images of NSCLC patients treated with radical radiotherapy to a dose ≥45 Gy with concurrent chemotherapy. Results: Sixty patients with locally advanced NSCLC were included; in 31 patients, the primary tumor was peripheral and thus suitable for contouring. There was a mean percent decrease of 40.2% by fraction 15 and 51.1% by treatment completion. Among all 60 patients, 19 patients (32%) had more than 30% regression by fraction 15 and 25 patients (81%) by treatment completion. Statistically significant tumor migration in at least one direction between the first and the last 2 weeks was demonstrated in 14 of 27 patients. Clinically relevant changes (atelectasis and effusions) were noted in 11 of 29 visually assessed patients. Conclusions: Current rcCBCT image quality allows assessment of tumors located more peripherally. Significant tumor regression was documented in the majority of patients. In view of these observations, the suitability of adaptive radiotherapy in radical lung cancer treatment should be further investigated.

The Canadian National System for Incident Reporting in Radiation Treatment (NSIR-RT) Taxonomy

PURPOSEnIncident investigation, reporting, and learning are core elements of quality improvement in radiation treatment. This report describes the development of a Canadian National System for Incident Reporting in Radiation Treatment (NSIR-RT), focusing especially on the taxonomy.nnnMETHODS AND MATERIALSnThe NSIR-RT was developed to provide a framework in Canada for reporting and analyzing radiation treatment incidents. A key objective was to assure compatibility with other international reporting systems to facilitate future information exchange. The Canadian community was engaged at every step of the development process through Delphi consensus building and inter-user agreement testing to promote awareness of the system and motivate broad-based utilization across the country.nnnRESULTSnThe final taxonomy was comprised of 6 data groups (impact, discovery, patient, details, treatment delivery, and investigation) and 33 data categories with predefined menu options. There was a high level agreement within the Canadian community about the final suite of data categories, and broad alignment of these categories with the World Health Organization and other American and European radiation treatment incident classifications.nnnCONCLUSIONSnThe Canadian NSIR-RT taxonomy will be implemented as an online, web-based reporting and analysis system. It is expected that the taxonomy will evolve and mature over time to meet the changing needs of the Canadian radiation treatment community and support radiation treatment incident learning on a global scale.

Lung sparing and dose escalation in a robust-inspired IMRT planning method for lung radiotherapy that accounts for intrafraction motion

PURPOSEnTo test the efficacy of a simple, robust-inspired intensity modulated radiotherapy (IMRT) planning strategy for lung radiotherapy designed to reduce lung dose and escalate tumor dose using realistic dose accumulation tools.nnnMETHODSnA deformable image registration tool was used to plan and accumulate dose over all phases of the breathing cycle for conventional and robust-inspired IMRT strategies of eight nonsmall cell lung cancer patients exhibiting peak-to-peak respiratory motion with amplitudes ranging from 1 to 2 cm in the craniocaudal direction. The authors robust-inspired plans were designed to have smaller beam apertures based on target location during exhale, combined with edge-enhanced intensity maps to ensure target coverage during inspiration. For these, a new planning target volume defined as the rPTV was generated from a 5-mm isotropic expansion of the clinical target volume (CTV) on end-exhale combined with a boost volume, set to 110% of the prescription dose. Plans were evaluated in terms of (i) lung sparing and (ii) dose escalation for mean lung dose (MLD) isotoxicity. CTV and planning target volumes (PTV) coverage and lung dose were compared to the conventional IMRT approach.nnnRESULTSnRobust-inspired plans showed potential lung dose reductions in seven out of eight patients. For non-GTV lung, percent reductions of 3%-14% in MLD and 6%-15% in V20 were observed. For seven of eight cases, the robust-like approach yielded increased accumulated doses to CTV. Isotoxicity studies for MLD showed increased dose to the CTV and the rPTV, in the range of 104%-118% and 95%-114% of prescription dose, respectively.nnnCONCLUSIONSnA 4D dose calculation based on deformable image registration was used to evaluate a robust-inspired planning strategy for lung radiotherapy. This method offers notable reductions to lung dose while improving tumor coverage through the use of reduced geometric margins combined with edge enhancements.PURPOSEnTo test the efficacy of a simple, robust-inspired intensity modulated radiotherapy (IMRT) planning strategy for lung radiotherapy designed to reduce lung dose and escalate tumor dose using realistic dose accumulation tools.nnnMETHODSnA deformable image registration tool was used to plan and accumulate dose over all phases of the breathing cycle for conventional and robust-inspired IMRT strategies of eight nonsmall cell lung cancer patients exhibiting peak-to-peak respiratory motion with amplitudes ranging from 1 to 2 cm in the craniocaudal direction. The authors robust-inspired plans were designed to have smaller beam apertures based on target location during exhale, combined with edge-enhanced intensity maps to ensure target coverage during inspiration. For these, a new planning target volume defined as the rPTV was generated from a 5-mm isotropic expansion of the clinical target volume (CTV) on end-exhale combined with a boost volume, set to 110% of the prescription dose. Plans were evaluated in terms of (i) lung sparing and (ii) dose escalation for mean lung dose (MLD) isotoxicity. CTV and planning target volumes (PTV) coverage and lung dose were compared to the conventional IMRT approach.nnnRESULTSnRobust-inspired plans showed potential lung dose reductions in seven out of eight patients. For non-GTV lung, percent reductions of 3%-14% in MLD and 6%-15% in V20 were observed. For seven of eight cases, the robust-like approach yielded increased accumulated doses to CTV. Isotoxicity studies for MLD showed increased dose to the CTV and the rPTV, in the range of 104%-118% and 95%-114% of prescription dose, respectively.nnnCONCLUSIONSnA 4D dose calculation based on deformable image registration was used to evaluate a robust-inspired planning strategy for lung radiotherapy. This method offers notable reductions to lung dose while improving tumor coverage through the use of reduced geometric margins combined with edge enhancements.