Hypofractionated radiation therapy for early breast cancer: Follow up of a new treatment standard.

AIM: To assess the oncological outcomes of patients with early breast cancer treated with breast-conserving surgery and adjuvant hypofractionated radiation therapy. METHODS AND MATERIAL: This retrospective analysis included all patients ≥50 year of age with T1-2 N0 M0 breast cancer treated at our Radiation Oncology Unit between 2008 and 2011. Whole-breast radiation therapy was delivered to a dose of 42.5 Gy in 16 fractions, without boost. The primary outcome was local control. RESULTS: 212 patients were identified. With a median follow up of 60 months, we found 3% local recurrence and 5.3% regional and/or distant recurrences. At the moment of data analysis, 17 patients had died. Out of 5 local recurrences, 2 had previously had a distant recurrence, both of them died. The other three were still alive at the last follow up. These results are comparable to those observed in Phase III trials that use this fractionation scheme. CONCLUSIONS: The results obtained with this retrospective analysis are comparable to those obtained in large randomized trials. This data also supports the use of hypofractionated radiation therapy in Latin America. Hypofractionated radiation therapy for early breast cancer patients should be the standard adjuvant treatment.

Cardiac risk and MCNP/SISCODES doses in RT of the left internal mammary chain with photon and electron portals.

AIM: The present study evaluated the increment of cardiac risk (CR) and absorbed dose in radiotherapy of the internal mammary chain (IMC), in particular with photon portals of 4 6 MV, and cobalt therapy (Co60); and, electron portals of 8, 12 and 16 MeV applied in the left breast, considering the adoption of a combined photon (16 Gy) and electron (30 Gy) protocols. MATERIALS AND METHODS: The modified ICRP-reference female model of 60 kg, 163 cm and 43 years of age, coil RCP-AF, was modelled. The MCNP6/SICODES codes were employed, where the spatial dose distributions and dose-volume histograms were generated. Toxicity limits and a CR model were considered. RESULTS: CR associated with the 6 MV, 4 MV and Co60 portals increased 41.1; 40.6 and 34.5%, respectively; while, in 8, 12 and 16 MeV portals, they were 5.0, 32.5 and 49.2%, respectively. High anomalous scatter radiation from electron portals was found in the left lung providing an average dose of 3.3-5.0 Gy. CONCLUSIONS: To RCP-AF, the Co60 portal for IMC-RT presented more attractive dose distribution, whose 16 Gy for photon-component produced less CR increase, 5% lower than the other photon portals. Considering electron portals, the smallest CR increase was produced by 8 MeV portal while 12-16 MeV made the risk higher. There is a call for a less hardened energetic spectrum in order to reduce CR; however, holding suitable IMC penetration. A combined Co60/8-12 MeV may bring benefits, reducing CR. The lowest risk was found to 46 Gy electron portals exclusively.

A detailed evaluation of TomoDirect 3DCRT planning for whole-breast radiation therapy.

The goal of this work was to develop planning strategies for whole-breast radiotherapy (WBRT) using TomoDirect three-dimensional conformal radiation therapy (TD-3DCRT) and to compare TD-3DCRT with conventional 3DCRT and TD intensity-modulated radiation therapy (TD-IMRT) to evaluate differences in WBRT plan quality. Computed tomography (CT) images of 10 women were used to generate 150 WBRT plans, varying in target structures, field width (FW), pitch, and number of beams. Effects on target and external maximum doses (EMD), organ-at-risk (OAR) doses, and treatment time were assessed for each parameter to establish an optimal planning technique. Using this technique, TD-3DCRT plans were generated and compared with TD-IMRT and standard 3DCRT plans. FW 5.0cm with pitch = 0.250cm significantly decreased EMD without increasing lung V20Gy. Increasing number of beams from 2 to 6 and using an additional breast planning structure decreased EMD though increased lung V20Gy. Changes in pitch had minimal effect on plan metrics. TD-3DCRT plans were subsequently generated using FW 5.0cm, pitch = 0.250cm, and 2 beams, with additional beams or planning structures added to decrease EMD when necessary. TD-3DCRT and TD-IMRT significantly decreased target maximum dose compared to standard 3DCRT. FW 5.0cm with 2 to 6 beams or novel planning structures or both allow for TD-3DCRT WBRT plans with excellent target coverage and OAR doses. TD-3DCRT plans are comparable to plans generated using TD-IMRT and provide an alternative to conventional 3DCRT for WBRT.