Variability in axillary lymph node delineation for breast cancer radiotherapy in presence of guidelines on a multi-institutional platform.

AIM: To quantify the variability between radiation oncologists (ROs) when outlining axillary nodes in breast cancer. MATERIAL AND METHODS: For each participating center, three ROs with different levels of expertise, i.e., junior (J), senior (S) and expert (E), contoured axillary nodal levels (L1, L2, L3 and L4) on the CT images of three different patients (P) of an increasing degree of anatomical complexity (from P1 to P2 to P3), according to contouring guidelines. Consensus contours were generated using the simultaneous truth and performance level estimation (STAPLE) method. RESULTS: Fifteen centers and 42 ROs participated. Overall, the median Dice similarity coefficient was 0.66. Statistically significant differences were observed according to the level of expertise (better agreement for J and E, worse for S); the axillary level (better agreement for L1 and L4, worse for L3); the patient (better agreement for P1, worse for P3). Statistically significant differences in contouring were found in 18% of the inter-center comparison. Less than a half of the centers could claim to have a good agreement between the internal ROs. CONCLUSIONS: The overall intra-institute and inter-institute agreement was moderate. Central lymph-node levels were the most critical and variability increased as the complexity of the patient's anatomy increased. These findings might have an effect on the interpretation of results from multicenter and even mono-institute studies.

Three-dimensional conformal radiotherapy, static intensity-modulated and helical intensity-modulated radiotherapy in glioblastoma. Dosimetric comparison in patients with overlap between target volumes and organs at risk.

AIMS AND BACKGROUND: Radiotherapy is the standard treatment of glioblastoma. Three-dimensional conformal radiotherapy is the standard technique to treat glioblastoma. Intensity-modulated radiotherapy and helical intensity-modulated radiotherapy (tomotherapy) are becoming widely used. The present study compared three-dimensional conformal radiotherapy, intensity-modulated radiotherapy and tomotherapy in terms of target coverage and preservation of organs at risk. METHODS: Ten patients treated with three-dimensional conformal radiotherapy, with a target volume close to or superimposed to the organs at risk, were retrospectively selected. The plans were re-planned with step-and-shoot 3/5 fields intensity-modulated radiotherapy and tomotherapy. Target coverage and sparing of organs at risk were statistically compared. RESULTS: Mean planning target volume V95% improved with sophisticated techniques (87.2%, 93.2%, 97.6% with three-dimensional conformal radiotherapy, intensity-modulated radiotherapy and tomotherapy, respectively). The comparison of three-dimensional conformal radiotherapy and intensity-modulated radiotherapy did not show significant differences, whereas differences were significant when three-dimensional conformal radiotherapy and tomotherapy as well as intensity-modulated radiotherapy and tomotherapy were compared. Mean planning target volume/clinical target volume D99-D98-D95 were not different between three-dimensional conformal radiotherapy and intensity-modulated radiotherapy, but they were different between tomotherapy and three-dimensional conformal radiotherapy and intensity-modulated radiotherapy, with better clinical target volume/and planning target volume coverage with the tomotherapy plans. Brain D33/66 were 31.1/11.8 Gy, 37.5/18.3 Gy and 28.5/14.7 Gy with three-dimensional conformal radiotherapy, intensity-modulated radiotherapy and tomotherapy, respectively. Mean brainstem, optic nerves and chiasma Dmax were always within the defined constraints. The homogeneity index improved with intensity-modulated radiotherapy/tomotherapy compared to three-dimensional conformal radiotherapy. Tomotherapy was better than intensity-modulated radiotherapy in all patients. CONCLUSIONS: In this selected group of patients, a significant dosimetric advantage was evident for tomotherapy compared with three-dimensional conformal radiotherapy and intensity-modulated radiotherapy. Significant advantages were evident in terms of panning target volume coverage (V95), D99, D98 and D95. The clinical significance of the results should be defined.

Radiotherapy in low-grade glioma adult patients: a retrospective survival and neurocognitive toxicity analysis.

PURPOSE: The treatment of low-grade glioma is still debated. Surgery is the first-line approach, and the correct timing of radiation therapy has not yet been defined since "early" radiation therapy improves relapse-free survival but not overall survival. Since a longer progression-free survival is desirable, the main issue related to radiotherapy is the incidence of late neurocognitive toxicity. MATERIALS AND METHODS: Ninety-five patients with low-grade glioma were consecutively treated with early (within 3 months) or late (at disease progression) post-surgical radiation therapy. Clinical and therapeutic factors were entered into the analysis overall (OS) and progression-free (PFS) survival, and the distribution in two accrual periods identified based on the evolution of imaging procedures and radiotherapy techniques were compared. For 6/18 long survivors (LS) without evidence of disease, neurocognitive evaluation was obtained and the dose to the hippocampus region was retrospectively calculated. RESULTS: Univariate analysis of OS showed a statistically significant advantage for grade 1 and oligodendroglioma histology, better performance status [Karnofsky index (KI)], age <40 years, radical surgery, no steroid treatment; PFS was significantly related with younger age, better KI and "early" radiotherapy. Multivariate analysis of OS confirmed the significance of all variables except surgery; for PFS, only "early" radiotherapy and better KI retained significance. Memory impairment was evident in 4/6 of the LS tested; quality of life was good and executive functions were normal. CONCLUSION: Radiotherapy remains an essential component in the treatment of low-grade glioma. Prospective studies are needed to evaluate the relative contributions of the disease itself and of surgery, radiation and chemotherapy to long-term neurocognitive damage.