Pilot study of sole conformal peroperative interstitial brachyradiotherapy of early stage breast carcinoma using...

In this study of high-dose-rate brachyradiotherapy to the lumpectomy site as the sole radiation are documented a three-dimensional treatment planning and preliminary results of accelerated partial- breast irradiation. From March 2002 to July 2004 25 patients were prospectively included in this study. Six patients were excluded becuase of definitive histology of lobular carcinoma or positive margin. The median age was 63.2 years (range: 44-77 years). Median follow-up of all patients is 11 months (range: 3-25 months) with a minimum follow-up of 3 months. Radiation was delivered using the high-dose-rate remote afterloader VariSource with [192]Ir source. The patients received radiation twice a day at least 6 hours apart for a total of 10 fractions over five days with a single dose of 3.4 Gy. The total dose was 34.0 Gy prescribed as a minimum peripheral dose to match or minimally exceed the volume defined by the surgical clips as seen on CT scans. Freehand technique allows conformal placement of the catheters to the shape of the lumpectomy cavity. We use the method of geometric optimalisation which allows the calculations of dose distribution in relation to target. At a median follow-up of 11 months none of patients developed in-field breast recurrences, one patient had out-of-field recurrences. There were no regional nodal recurrences. At each patient, there was calculated target volume size in cm3 (median 91.3 cm3) dose volume histogram (DVH), dose homogenity index (DHI). Median DHI was 0.42. Median volume of breast tissue getting 100% of the prescription dose, V(100), is 87%; and V(150) 48.5%. We have noticed two treatment complications: hematoma and abscess in the place of tumorous bed after exstirpation. At last follow-up, patients rated the overall cosmetic outcome excellent. This method is suitable just for patients with histologically confirmed small tumors (<3 cm in diameter) without negative prognostic factors for local recurrence (age at least 40 years, negative surgical margins, nodal involvement - maximum three positive nodes without extracapsular extension).