Worldwide breast cancer is the most common malignancy in women. In the developed world, it is responsible for 18 percent of all cases of cancers seen in women. One million new cases of breast cancer are registered worldwide every year and it is the single commonest cause of death among women in the 40- 50 years age group. In India breast cancer is the second commonest cancer seen in the women after carcinoma cervix. Its prevalence is higher in urban women and it accounts for 20% of all cancer related diseases. In Mumbai and Delhi, it is the commonest malignancy seen in women. In India it has an incidence of 17-40 cases per 1, 00,000 population and the 5 years survival is 42.3 percent to 46.8 percent.
Conventionally radiotherapy in early breast cancers is done by the whole breast technique which utilizes two tangential ports. Upper margin of the radiotherapy field lies at the first intercostals space, and the lower margin lies 2 cm below the inferior mammary line. Medial margin is in the midsternal line and the lateral margin is at the mid axillary line. A total dose of 50 Gy in 25 fractions is given over 5 weeks by conventional fractionation followed by boost of 10-20 Gy. This technique is easy to setup, and avoids the junction dose. Computerizes planning is done for dose optimization. Standard 2d treatment (conventional radiotherapy) techniques utilizes a simplistic view of patient anatomy and it creates hot spot because lung transmission is not accurately included and thinner regions of breast (superior and inferior) are modeled like the thickest slice of the breast. Thus conventional radiotherapy has limitations in the treatment of breast cancer and these include.