Fecal incontinence and radiation dose on anal sphincter in patients with locally advanced rectal cancer (LARC) treated with preoperative chemoradiotherapy: a retrospective, single-institutional study.

BACKGROUND: The objective of the study is to determine the correlations among the variables of dose and the sphincter function (SF) in patients with locally advanced rectal cancer treated with preoperative capecitabine/radiotherapy followed by low anterior resection (LAR) + TME. METHODS: We retrospectively reviewed 92 consecutive patients with LARC treated at our center with LAR from 2006 and more than 2 years free from disease. We re-contoured the anal sphincters (AS) of patients with the help of the radiologist. SF was assessed with the Wexner scale (0-20 points, being punctuation inversely proportional to annal sphincter functionality). All questionnaires were filled out between January 2010 and December 2012. Dosimetric parameters that have been studied include V 20, V 30, V 40, V 50, mean dose (D mean), minimum dose (D min), D 90 (dose received by 90% of the sphincter) and D 98. STATISTICAL ANALYSIS: The correlations among the variables of dose and SF were studied by the Spearman correlation coefficient. Differences in SF relating to maximum doses to the sphincter were assessed by the Mann-Whitney test. RESULTS: Mean Wexner score was 5.5 points higher in those patients with V 20 > 0 compared to those for which V 20 = 0 (p = 0.008). In a multivariate regression model, results suggest that the effect of V 20 on poor anal sphincter control is independent of the effect of distance, with an adjusted OR of 3.42. CONCLUSIONS: In order to improve the SF in rectal cancer treated with preoperative radiotherapy/capecitabine followed by conservative surgery, the maximum radiation dose to the AS should be limited, when possible, to <20 Gy.

Influence of different treatment techniques and clinical factors over the intrafraction variation on lung stereotactic body radiotherapy.

PURPOSE: In the present study we compared three different Stereotactic body radiation therapy (SBRT) treatment delivery techniques in terms of treatment time (TT) and their relation with intrafraction variation (IFV). Besides that, we analyzed if different clinical factors could have an influence on IFV. Finally, we appreciated the soundness of our margins. MATERIALS AND METHODS: Forty-five patients undergoing SBRT for stage I lung cancer or lung metastases up to 5 cm were included in the study. All underwent 4DCT scan to create an internal target volume (ITV) and a 5 mm margin was added to establish the planning target volume (PTV). Cone-beam CTs (CBCTs) were acquired before and after each treatment to quantify the IFV. Three different treatment delivery techniques were employed: fixed fields (FF), dynamically collimated arcs (AA) or a combination of both (FA). We studied if TT was different among these modalities of SBRT and whether TT and IFV were correlated. Clinical data related to patients and tumors were recorded as potential influential factors over the IFV. RESULTS: A total of 52 lesions and 147 fractions were analyzed. Mean IFV for x-, y- and z-axis were 1 ± 1.16 mm, 1.29 ± 1.38 mm and 1.17 ± 1.08 mm, respectively. Displacements were encompassed by the 5 mm margin in 96.1 % of fractions. TT was significantly longer in FF therapy (24.76 ± 5.4 min), when compared with AA (15.30 ± 3.68 min) or FA (17.79 ± 3.52 min) (p < 0.001). Unexpectedly, IFV did not change significantly between them (p = 0.471). Age (p = 0.003) and left vs. right location (p = 0.005) were related to 3D shift ≥2 mm. In the multivariate analysis only age showed a significant impact on the IFV (OR = 1.07, p = 0.007). CONCLUSIONS: The choice of AA, FF or FA does not impact on IFV although FF treatment takes significantly longer treatment time. Our immobilization device offers enough accuracy and the 5 mm margin may be considered acceptable as it accounts for more than 95 % of tumor shifts. Age is the only clinical factor that influenced IFV significantly in our analysis.

Impact of initial FDG PET/CT in the management plan of patients with locally advanced head and neck cancer.

OBJECTIVE: To determine the impact of initial FDG PET/CT staging on clinical stage and the management plan in patients with locally advanced head and neck cancer (LAHNC). MATERIALS AND METHODS: We retrospectively reviewed the records of 72 consecutive patients (2007-2010) staged with PET/CT and conventional CT with tumours of hypopharynx/larynx (26 patients, 36 %), oral cavity (17 patients, 24 %), oropharynx (16 patients, 22 %), nasopharynx (12 patients, 17 %), and others (2 %). The impact of PET/CT on management plans was considered high when PET/CT changed the planned treatment modality or treatment intent, and intramodality changes were considered as minor changes with low impact. RESULTS: FDG PET/CT changed the stage in 27 patients and had high impact on the management plan in 12 % of patients (detection of distant metastases in 6 patients and stage II in 2 patients). Intramodality changes were more frequent: FDG PET/CT altered the TNM stage in 18/72 (25 %) of patients, upstaging N stage in 90 % of patients with low impact. CONCLUSIONS: Initial FDG PET/CT staging not only improves stage but also affects the management plan in LAHNC patients.