Lumpectomy with or without Irradiation in Women 70 Years of Age or Older with the Early Breast Cancer

In our study, 11.4% of the patients did not undergo axillary surgery. Similar outcomes were seen in clinical node-negative elderly breast cancer patients with and without axillary surgery. In the study of Martelli et al., after a median follow-up of 15 years, they found breast cancer-specific mortality similar in both groups. [] Better quality of life was noted in patients who did not undergo axillary surgery. It has also been reported that sentinel lymph node biopsy could be omitted in elderly patients.[] In a study conducted with patients, over 70 years of age who underwent breast-conserving surgery and did not undergo axillary surgery or radiotherapy, after a median follow-up of 60 months, no significant differences in local recurrence, distant metastasis, and breast cancer cancer-specific death were observed. IBTR rate was 1.6% in these patients and 5.3% in the others.[]

In our study, the proportion of patients without axillary staging was 5.7% in the radiotherapy group and 29.4% in the non-irradiated group (p=0.007). This situation makes us think that axillary surgery and radiotherapy were applied to patients who were thought to be in the high-risk group. However, our study found no relationship between radiotherapy application and factors other than age associated with local recurrence or survival.

In our study, 75.7% of the patients received radiotherapy. Soulos et al. showed that the rate of radiotherapy after breast-conserving surgery in patients aged 70 years and older with T1N0M0 breast cancer was 79% before and 75% after the Cancer and Leukemia Group B C9343 study.[] In another study conducted with patients over the age of 70, the rate of application was found to be 75%. In this study, as in our study, radiotherapy usage decreased with age.[]

The 5-year OS was 81% and 100%, respectively (p=0.078). The 5-year BCSS was 97% in the radiotherapy group and 100% in the non-irradiated group (p=0.222); PFS 83% and 84% (p=0.622); IBTRFS 87% and 100% (p=0.113); and DMFS 93% and 100% , respectively (p=0.275). The rate of DMFS was significantly lower in the triple-negative group. Fiveyear DMFS was 67% in triple (-) group, 93% in HR (+) HER2 (-) group, and 100% in HER2 (+) group (p=0.036). After a median follow-up of 42 months (3- 169), five patients had ipsilateral breast recurrence, one patient had regional recurrence (axilla), three patients had DM, and nine patients died. Two of the patients died of breast cancer, and seven patients died from other causes (One COVID-19 infection, one diabetic coma, two secondary neoplasms, and three dementia). There were no differences in recurrence and death rates in patients who received and did not receive radiotherapy. Of the patients who died, 77.8% died from causes other than breast cancer. Our findings are compared with the results in the literature below.

In study C9343, there was no difference in 5-year OS and disease-free survival rates between patients who received and did not receive radiotherapy. The locoregional recurrence rate was 1% in the arm with RT and 4% without RT.[] In the study containing the long-term follow-up results of this study, after a median follow-up of 12 years, 8% less locoregional recurrence and 7% less IBTR were found in the arm that received radiotherapy. Similar to the previous study, there was no difference in OS and disease-free survival rates.[]

The Early Breast Cancer Trialists" Collaborative Group 2005 meta-analysis reported a significant reduction in mortality at 15 years with RT, but this only applied if the difference in IBTR was >10%.[] In most of the studies, the difference in IBTR was below 10%.

We thought that there would be less time for local recurrence with the short life expectancy in elderly patients. However, in our study, the median OS was 119 months (94-145) in the radiotherapy arm and 141 months (136-167) in the non-irradiated are. Longterm follow-up of the CALBG study found a median survival of 12 years, with IBTR rates still low.[]

In the PRIME II study, after a median follow-up of 5 years, the absolute risk reduction in ipsilateral tumor recurrence with radiotherapy after breast-conserving surgery was 2.9%. It was stated that there was no survival advantage, and most of the deaths were due to causes other than breast cancer. This study argued that the reduction in absolute risk was low enough for radiotherapy omission.[]

The German Breast Cancer Group found the ipsilateral breast tumor recurrence rate in the adjuvant endocrine treatment alone arm to be 6% and 2% when radiotherapy was added. Patients aged 45 years and older were included in this study.[]

Tinterri et al.,[] after 5 years of median follow-up, the incidence of IBR was 2.5% in the surgery-only arm and 0.7% in the surgery plus radiotherapy arm. Patients aged 55-75 years who received systemic therapy were included in this study.

Livi et al.[] found breast relapse rates of 3.4% in the arm that received radiotherapy and 10.6% in the arm that did not. Breast relapse decreased with increasing age (especially over 75). They reported that omission of radiotherapy was safe in breast cancer patients over 75 years of age who underwent T1-2 quadranectomy.

Despite the differences in design, no study showed significant differences in distant disease-free survival or OS, although all showed some decrease in IBTR with radiotherapy. Differences in local control are primarily due to inclusion criteria.[]

As a result of these studies, changes were made + in the National Comprehensive Cancer Network guidelines.[] Despite these changes, one of the reasons why radiotherapy application rates are still high is that with newly developed radiotherapy techniques, patients are treated in a shorter time with fewer side effects. Today, with accelerated partial breast irradiation (APBI), organs at risk are better protected without irradiation of the entire breast. Hypofractionated radiotherapy can be applied in a shorter time cost-effectively.

Studies on breast cancer in female patients aged 65 and over in our country are limited.[] A review emphasizes that local recurrence decreases with age, and thus, the necessity of radiotherapy in elderly patients is not as clear as in younger patients. However, there are also studies suggesting that elderly patients will benefit more from radiotherapy than younger patients.[]

One of the limitations of our study is that we did not specify APBI and hypofractionated radiotherapy applications in patients who received radiotherapy. In addition, selection bias cannot be avoided due to the retrospective nature of our study. We did not indicate if radiotherapy omission was the result of the patient's preference or the clinician"s guidance.

As a result, in our study, the rate of radiotherapy application in low-risk breast cancer patients over 70 was similar to that in the literature. Radiotherapy usage decreased with age. There were no differences in recurrence and death rates in patients who received and did not receive radiotherapy. Most of the deaths were due to causes other than breast cancer. Comorbidities and the biology of the tumor, not specific breast cancer treatments, dictated death and recurrence rates.

Peer-review: Externally peer-reviewed.

Conflict of Interest: All authors declared no conflict of interest.

Ethics Committee Approval: The study was approved by the Muğla Sıtkı Koçman University Medical and Health Sciences Ethics Committee (No: 22, Date: 04/04/2022).

Financial Support: None declared.

Authorship contributions: Concept - G.E., K.A.; Design - K.A.; Supervision - K.A.; Funding - None; Materials - K.A.; Data collection and/or processing - G.E.; Data analysis and/ or interpretation - G.E.; Literature search - G.E.; Writing - G.E; Critical review - K.A.