Post Mastectomy Radiotherapy for High Risk T1-T2N0 Breast Cancer …. Does it Make Difference?

Background: Early breast cancer cases usually have good prognosis and long-
term survival. but a subgroup of them develop locoregional failure. Studying 
those cases have shown that they have multiple risk factors such as tumor site 
and size, menopausal and hormonal status, also presence or absence of 
lymphovascular invasion (LVI). Many radiotherapists still confused about 
giving adjuvant radiotherapy to that group of patients. This study seeks to 
document our experience about detecting the high-risk factors for local failure in 
T1-T2 N0 breast cancer cases after mastectomy. Also, to identify if this 
subgroup could have a benefit from post mastectomy radiation therapy. 
Methods: This is a retrospective study of 588 cases of node-negative early (T1-
2) invasive breast carcinoma. After surgery and systemic treatment and when 
considering adjuvant radiation therapy, 310 cases received post mastectomy 
radiation therapy while 278 cases did not. Risk factors were identified for all 
cases which include; (1) medial site tumors, (2) size more than 4 cm, (3) 
premenopausal status (4) positive LVI (5) triple negative cases. cases with more 
than 2 risk factors were also examined in both groups to assess the effect of 
accumulated risk factors. Time of local failure if happened and duration of 
disease-free survival were reported. 
Results: Patients characteristics are matched between the 2 groups. At the end 
of the study, 18 cases (5.8%) in group 1 developed local recurrence compared 
with 29 cases (10.4%) in group 2 with 0.039 P value. The incidence of LRR is 
higher in cases presented with risk factors specially when more than 2. 
Considering the effect of PMRT; disease free survival was better in all risky 
subgroups in group 1 compared to group 2. Although P value was not 
significant when assessing every risk factor alone, but it was significant when 
there were more than 2 risk factors (mean disease-free survival was 96.28 
months in group 1 compared to 82.76 months in group 2 with 0.015 P value). 
Conclusion: we concluded that there are multiple risk factors for locoregional 
recurrence in early node-negative breast cancer patients after mastectomy. Cases 
presented with those factors (specially when more than 2) could have a benefit 
from post mastectomy radiation therapy