Chest wall pain following lung stereotactic body radiation therapy using 48Gy in three fractions: A search for predictors.

PURPOSE: Chest wall pain is an uncommon but bothersome late complication following lung stereotactic body radiation therapy. Despite numerous studies investigating predictors of chest wall pain, no clear consensus has been established for a chest wall constraint. The aim of our study was to investigate factors related to chest wall pain in a homogeneous group of patients treated at our institution. PATIENTS AND METHODS: All 122 patients were treated with the same stereotactic body radiation therapy regimen of 48Gy in three fractions, seen for at least 6 months of follow-up, and planned with heterogeneity correction. Chest wall pain was scored according to the Common Terminology Criteria for Adverse Events classification v3.0. Patient (age, sex, diabetes, osteoporosis), tumour (planning target volume, volume of the overlapping region between planning target volume and chest wall) and chest wall dosimetric parameters (volumes receiving at least 30, 40, and 50Gy, the minimal doses received by the highest irradiated 1, 2, and 5cm3, and maximum dose) were collected. The correlation between chest wall pain (grade 2 or higher) and the different parameters was evaluated using univariate and multivariate logistic regression. RESULTS: Median follow-up was 18 months (range: 6-56 months). Twelve patients out of 122 developed chest wall pain of any grade (seven with grade 1, three with grade 2 and two with grade 3 pain). In univariate analysis, only the volume receiving 30Gy or more (P=0.034) and the volume of the overlapping region between the planning target volume and chest wall (P=0.038) significantly predicted chest wall pain, but these variables were later proved non-significant in multivariate regression. CONCLUSION: Our analysis could not find any correlation between the studied parameters and chest wall pain. Considering our present study and the wide range of differing results from the literature, a reasonable conclusion is that a constraint for chest wall pain is yet to be defined.

A systematic review of organ motion and image-guided strategies in external beam radiotherapy for cervical cancer.

Advanced radiotherapy techniques, such as intensity-modulated radiotherapy (IMRT), may significantly benefit cervical cancer patients, in terms of reducing late toxicity and potentiating dose escalation. Given the steep dose gradients around the planning target volume (PTV) with IMRT planning, internal movement of organs during treatment may cause geographical miss of the target and unnecessary organs at risk (OAR) inclusion into high dose regions. It is therefore important to consider the extent and patterns of organ motion and to investigate potential image-guided radiotherapy (IGRT) solutions before implementing IMRT for cervical cancer. A systematic literature search was carried out using Medline, Embase, Cochrane Library, Web of Science, Cinahl and Pubmed. Database-appropriate search strategies were developed based upon terms for uterine neoplasms, IGRT, organ motion and target volume. In total, 448 studies were identified and screened to find 39 relevant studies, 12 of which were abstracts. These studies show that within the target volume for cervical cancer radiotherapy, uterine motion is greater than cervical. Uterine motion is predominantly influenced by bladder filling, cervical motion by rectal filling. Organ motion patterns are patient specific, with some having very little (5 mm) and others having much larger shifts (40 mm) of the target volume. Population-based clinical target volume (CTV)-PTV margins would be large (up to 4 cm around the uterus), resulting in unnecessary OAR inclusion within the PTV, reducing the benefits of IMRT. Potential solutions include anisotropic margins with increased margins in the anteroposterior and superoinferior directions, or greater PTV margins around the uterine fundus than the cervix. As pelvic organ motion seems to be patient specific, individualised PTV margins and adaptive IGRT strategies have also been recommended to ensure target volume coverage while increasing OAR sparing. Although these strategies are promising, they need significant validation before they can be adopted into clinical practice.