Combination of surgical method and radiation therapy in the treatment of early breast cancer
After surgery, the frequency of local recurrences in the chest wall, ipsilateral lymph nodes or in the contralateral mammary gland is 7-30%. It is further increased in the case of large tumors (> 5 cm) or if axillary lymph nodes are affected. When prescribing a course of radiation therapy after surgery, especially in patients with lesions of the axillary lymph nodes, the frequency of local recurrences is significantly reduced. However, most studies have not shown an increase in the survival rate of patients with lesions of the axillary lymph nodes who have undergone radiation therapy.
The exception is one important observation of patients in the period of premenopause who were prescribed a course of radiation therapy after the operation. A total of 1,708 people were observed who were irradiated after a mastectomy operation with axillary lymph nodes removed. A comparison was made with a group that did not receive a course of radiotherapy. 10 years after the operation, there was a decrease in the incidence of local recurrences (9% compared with 32%), increased overall (54% vs. 45%) and relapse-free (48% vs. 34%) survival. This and some other studies in many ways contribute to the development of a new view on the nature of breast cancer, since local treatment of a tumor usually does not affect the appearance of remote relapses of the disease and the overall survival of patients.
Obviously, local irradiation plays a critical role in relation to local recurrences. This is well supported by data from a study conducted in Cambridge as part of the Cancer Research Campaign (CRC).
In one prospectively randomized study, the results of simple mastectomy were compared with or without subsequent irradiation. The comparison showed that after radiation therapy, the frequency of local relapses is indeed reduced (from 30% to 11% after 10 years of observation), but this does not affect the survival of patients.
A different irradiation technique is used. For example, some radiologists prefer not to irradiate regional lymph nodes in patients undergoing mastectomy, in cases where there are no histological signs of axillary lymph nodes. It is limited to the irradiation of the chest. Patients with axillary lymph nodes removed usually try to avoid irradiation of the axillary region, of course, if there is no evidence of a more extensive spread of the tumor. The figure below illustrates an example of the location of radiation fields and dose distribution during radiation therapy.
The thesis on the minimization of surgical intervention and the maximum preservation of the breast was put forward by Keynes in London and later by Backless in Paris and Creel in the USA. Later, in a large series of works by Calle (Institute of Curie, Paris) and other surgeons, the safety and effectiveness of such operations was demonstrated. More than 1,000 cases of breast cancer have been observed in the works of Kalle. After 5 and 10 years after surgery, the same results were achieved as with the use of traditional surgical methods; only a minority of patients needed repeated surgery for localized relapses.
Almost half of the patients who underwent “sparing” mastectomy lived long enough. This suggests that local tumor recurrence, which occurs after “adequate” primary treatment, should not necessarily be accompanied by extensive metastasis.