There are two main surgical techniques for managing the tumour bed after breast cancer excision. Firstly, closing the defect by suturing the cavity walls together and secondly leaving the tumour bed open thus allowing seroma fluid to collect. There is debate regarding which technique is preferable, as it has been reported that a post-operative seroma increase post-operative infection rates and late normal tissue side effects.

Data from 648 patients who participated in the Cambridge Breast IMRT trial were used. Seromas were identified on axial CT images at the time of radiotherapy planning and graded as not visible/subtle or easily visible. An association was sought between the presence of seroma and the development of post-operative infection, post-operative haematoma and 2 and 5 years normal tissue toxicity (assessed using serial photographs, clinical assessment and self assessment questionnaire).

The presence of easily visible seroma was associated with increased risk of post-operative infection (OR = 1.80; p = 0.004) and post-operative haematoma (OR = 2.1; p = 0.02). Breast seroma was an independent risk factor for whole breast induration and tumour bed induration at 2 and 5 years. The presence of breast seroma was also associated with inferior overall cosmesis at 5 years. There was no significant association between the presence of seroma and the development of either breast shrinkage or breast pain.

The presence of seroma at the time of radiotherapy planning is associated with increased rates of post-operative infection and haematoma. It is also an independent risk factor for late normal tissue toxicity. This study suggests that full thickness surgical closure may be desirable for patients undergoing breast conservation and radiotherapy.