Pathologic Features of the Tumor
Tumor size is not a risk factor for local recurrence with T1 and T2 lesions, although it is possible that very small lesions might have a lower recurrence rate. Some studies suggest that tumors with lymphovascular invasion may be more likely to recur than those without this finding. Infiltrating lobular carcinoma is no more likely to be associated with local recurrence if the margins are negative. Due to the more diffuse growth characteristics of infiltrating lobular carcinoma, it is more difficult to obtain negative margins.
The grade of the tumor (state of differentiation) has not been associated with local recurrence.
Young age, defined variably as less than 35 and up to 50 years of age, is a risk factor for breast cancer recurrence. This has been reported in series from both the US and Europe in which younger patients, particularly those below age 30 at diagnosis, have a consistently higher local-regional relapse rate than older patients. This is unfortunate, as younger patients are often most interested in breast conservation.
While young age should not be a contraindication to breast conservation, it is an important part of the informed consent process. Kim et al at Memorial Sloan-Kettering Cancer Center demonstrated that young women had a higher local and a higher systemic failure rate than did matched older patients but that the two appeared to be independent of one another. Mastectomy with reconstruction may be appropriate in selected patients.
Adjuvant Radiation Therapy
Adjuvant radiation therapy reduces the incidence of local recurrence and is an essential part of BCT. Trials are ongoing to define the group in whom radiation can be safely omitted, but the current standard of care is to include radiation as an integral part of BCT. Alternative methods of radiation-therapy administration, including breast brachytherapy, have been proposed by Kuske and his colleagues at the Ochsner Clinic and bear further study.
The standard dose to the breast itself is 50 Gy, and many institutions give a boost dose of 12 Gy to the tumor bed. The value and/or necessity of the boost dose remains unknown. Two contraindications to the administration of radiation therapy include advanced connective-tissue disease, such as scleroderma, and a prior history of ionizing radiation to the breast.