Inherent change in MammoSite applicator three-dimensional geometry over time

Accelerated partial breast irradiation is commonly done with the MammoSite applicator, which requires symmetry to treat the patient. This paper describes three cases that were asymmetric when initially placed and became symmetric over time, without manipulation

The role of pre- and post-SRS systemic therapy in patients with NSCLC brain metastases

Purpose: We report our experience with stereotactic radiosurgery (SRS) for NSCLC brain metastases. We then assess the prognostic value of pre- and post-SRS systemic therapy (PrSST and PoSST) and evaluate the timing of PoSST.Methods: In this retrospective study, we analyzed 96 patients with lung cancer and ECOG PS ≤ 3 who underwent SRS during 2007-2013. Recorded factors included SRS treatment parameters, systemic status of disease (SDS) at time of SRS, and the use of PrSST and PoSST. SDS was designated as pulmonary disease or extrapulmonary disease. For analysis, the SRS-PoSST interval (SPI) was divided into ≤30 days and >30 days. Univariate and multivariate analyses were performed.Results: 85 patients with NSCLC were included in this analysis. 48% received PrSST and 48% received PoSST. 57% of patients had pulmonary disease while 40% had extrapulmonary disease. 46% of patients had synchronous metastases. At a median follow-up of 6 months, the median survival was 6.4 months and the actuarial overall survival at 3, 6, 12, and 36 months was 80%, 52%, 31%, and 6%. Extrapulmonary disease (p = 0.008) negatively predicted for survival while the receipt of any systemic therapy (p = 0.050) or PoSST alone (p = 0.039) positively predicted for survival. In patients receiving PoSST, an SPI >30 days positively predicted for survival (HR 0.28, 95% CI 0.13-0.62, p = 0.002) regardless of SDS.Conclusion: Our results indicate the prognostic importance of systemic therapy and specifically PoSST. Additionally, delaying the initiation of PoSST to >30 days seems beneficial. This finding was potentially influenced by neurotoxicity after SRS. Further investigation is warranted to define the optimal SPI

The role of pre- and post-SRS systemic therapy in patients with NSCLC brain metastases

Purpose: We report our experience with stereotactic radiosurgery (SRS) for NSCLC brain metastases. We then assess the prognostic value of pre- and post-SRS systemic therapy (PrSST and PoSST) and evaluate the timing of PoSST.Methods: In this retrospective study, we analyzed 96 patients with lung cancer and ECOG PS ≤ 3 who underwent SRS during 2007-2013. Recorded factors included SRS treatment parameters, systemic status of disease (SDS) at time of SRS, and the use of PrSST and PoSST. SDS was designated as pulmonary disease or extrapulmonary disease. For analysis, the SRS-PoSST interval (SPI) was divided into ≤30 days and &gt;30 days. Univariate and multivariate analyses were performed.Results: 85 patients with NSCLC were included in this analysis. 48% received PrSST and 48% received PoSST. 57% of patients had pulmonary disease while 40% had extrapulmonary disease. 46% of patients had synchronous metastases. At a median follow-up of 6 months, the median survival was 6.4 months and the actuarial overall survival at 3, 6, 12, and 36 months was 80%, 52%, 31%, and 6%. Extrapulmonary disease (p = 0.008) negatively predicted for survival while the receipt of any systemic therapy (p = 0.050) or PoSST alone (p = 0.039) positively predicted for survival. In patients receiving PoSST, an SPI &gt;30 days positively predicted for survival (HR 0.28, 95% CI 0.13-0.62, p = 0.002) regardless of SDS.Conclusion: Our results indicate the prognostic importance of systemic therapy and specifically PoSST. Additionally, delaying the initiation of PoSST to &gt;30 days seems beneficial. This finding was potentially influenced by neurotoxicity after SRS. Further investigation is warranted to define the optimal SPI.</p

Biological impact of geometric uncertainties: what margin is needed for intra-hepatic tumors?

<p>Abstract</p> <p>Background</p> <p>To evaluate and compare the biological impact on different proposed margin recipes for the same geometric uncertainties for intra-hepatic tumors with different tumor cell types or clinical stages.</p> <p>Method</p> <p>Three different margin recipes based on tumor motion were applied to sixteen IMRT plans with a total of twenty two intra-hepatic tumors. One recipe used the full amplitude of motion measured from patients to generate margins. A second used 70% of the full amplitude of motion, while the third had no margin for motion. The biological effects of geometric uncertainty in these three situations were evaluated with Equivalent Uniform Doses (EUD) for various survival fractions at 2 Gy (SF₂).</p> <p>Results</p> <p>There was no significant difference in the biological impact between the full motion margin and the 70% motion margin. Also, there was no significant difference between different tumor cell types. When the margin for motion was eliminated, the difference of the biological impact was significant among different cell types due to geometric uncertainties. Elimination of the motion margin requires dose escalation to compensate for the biological dose reduction due to the geometric misses during treatment.</p> <p>Conclusions</p> <p>Both patient-based margins of full motion and of 70% motion are sufficient to prevent serious dosimetric error. Clinical implementation of margin reduction should consider the tumor sensitivity to radiation.</p