Radiation therapy (RT) is an integral component of local therapy following breast conservation surgery in patients with breast carcinomas. It is typically delivered to the Whole breast by teletherapy techniques ranging from conventional to Intensity Modulated RT (IMRT). The conventionally fractionated whole breast RT treatment regimen usually takes six weeks to complete. More recent hypofractionated EBRT schedules have managed to reduce the overall treatment time, but it still takes at least 3 weeks for the entire course treatment.

A relatively new technique called Accelerated partial breast irradiation (APBI) is becoming widely accepted among the radiation oncologists treating breast cancer as well as the patients. The rationale behind APBI is that most of the local recurrences develop in close proximity to tumour bed; therefore, treating only the vicinity of resection cavity could potentially provide for equivalent local control rates, while simultaneously reducing toxicity by lowering the overall irradiated volumes. Small treatment volumes also enable larger fractional dose, thereby drastically reducing overall treatment time to less than 1 week.

There is now evidence to suggest that APBI is a suitable alternative to WBRT for selected patients.(10,11)There are different approaches to APBI like Multicatheter interstitial brachytherapy (MIBT), Single/multichannel balloon and hybrid device brachytherapy (BT) and EBRT techniques such as 3D-Conformal RT (3D-CRT), IMRT, Volume modulated arc therapy (VMAT) and proton therapy (3, 4). There are research works clinically and/or dosimetrically comparing between various APBI techniques and with WBI. (5-8) This study plans to retrospectively compare the tumor coverage, and normal tissue exposure with IMRT in patients treated with MIBT at our center and to report on early outcomes in terms of toxicity and local control.