We investigated the feasibility of breast conserving treatment (BCT) in patients with large (T2, T3) breast cancers, by combining preoperative radiotherapy and tissue replacement after wide excision by a myosubcutaneous flap transposition. The treatment consisted of 50 Gy whole breast irradiation followed by a 15-25 Gy iridium implant to the primary tumour with 2 cm margins. Four weeks after completion of the radiotherapy, wide excision of the original tumour area with a 1 cm margin and an axillary dissection was performed. In the same session the breast was reconstructed with an ipsilateral latissimus dorsi transposition flap. The treatment results in the first 6 patients are encouraging with respect to treatment toxicity and cosmetic outcome. The clinical tumour response after radiotherapy was difficult to evaluate. However, microscopic evaluation showed residual tumour in all specimens with (focal) involvement of the surgical margins in two. With a minimum follow-up of over 2.5 years no tumour recurrences in the breast have occurred.