ESTRO 2022 - Abstract Book

S1016

Abstract book

ESTRO 2022

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Our inclusion criteria included : • 1.All left sided breast cancer patients who underwent BCS • 2.PS 0-1 • 3.Age less than 60 • 4.No previous RT to breast • 5.No h/o any cardiac or lung disease • 6.Any patient with a comfortable breath hold for 20-25 sec o §

Simulation scans of both free breathing (FB) and ABC DiBHwere done on the same patient . § Tangent field with Field in field treatment plans with a dose prescription of 40 Gy/15frwere generated for each patient, in both the scans. UnPaired t test was the statistical test used to analyse the data and the level of significance was set at p < 0.05.

Results

o The median age group was 48 yrs. The mean threshold for breathhold was 1.2Lit .The mean duration of breathhold was 22 sec.The D mean of the heart in the FB technique was 431cGy and in the DIBH technique it was 245cGy, statistically significant with a p value of of <0.001. V30, in FB was 19 % and in DIBH group was 4% , with a p value of <0.001. The mean dose to LAD in FB was 350cGy and in DIBH it was 225cGy , reduced by 125cGy with a significant p value of 0.019 o The mean total lung volume in FB was 2411cc , and in DIBH group was 3636cc, with a significant p value of 0.001Similarly ipsilateral lung volume was 1624cc in DIBH arm and 1024cc in FB arm, with a p value of 0.001 . Mean lung dose ( D mean) of the total lung also reduced by 100cGy , but was not statistically significant o Another interesting parameter we analysedwas breath hold volume in litre .Correlation of breathhold with various dosimetric parameters using spearmans correlation coefficient was analysed.D mean of the heart , total lung volume and ipsilateral lung volume was found statistically significant with p values of 0.002, 0.007, 0.006 respectively

Conclusion •

We can conclude that DIBH with ABC technique has a significant impact on LAD and heart doses. • This should be the standard of care of RT for all left sided breast caners, for the amount of benefit it gives in preventing long term cardiac morbidity.

PO-1195 External beam re-irradiation for locally recurrent breast cancer.

F.A. Lima Aires 1 , C. Sá 1 , C. van der Elzen 1 , D. Queirós Inácio 1 , P. Meireles 1 , M.G. Pinto 1

1 Centro Hospitalar Universitário São João, Radioncology, Porto, Portugal

Purpose or Objective Mastectomy is standard for recurrence of breast cancer after breast conservation therapy (BCS) with whole breast irradiation (WBI). Reirradiation poses a distinct therapeutic challenge owing to risks associated with exceeding normal tissue tolerances and possibly more therapeutically resistant disease biology. Partial breast irradiation (PBI) has emerged as a viable alternative to whole breast irradiation in selected patients undergoing initial breast conservation. We report our experience with partial breast reirradiation (PBrI) for local recurrent breast cancer.

Materials and Methods