Abstract P1-10-05: Omitting radiotherapy in women ≥ 65 years with early breast cancer and favorable histopathology after breast-conserving surgery, sentinel node biopsy and adjuvant endocrine therapy is safe

Background: The benefit of radiotherapy in older women with endocrine responsive early breast cancer treated with breast-conserving surgery and endocrine therapy is unclear. The aim of this study was to verify if omission of radiotherapy in a predefined cohort of patients with good prognosis early breast cancer after breast conservation is safe.

Methods: Eligibility criteria were: consecutive patients with age ≥ 65 years, breast-conserving surgery (sector resection + sentinel node biopsy), clear margins, unifocal T 1 N0, Elston grade 1 and 2, estrogen receptor-positive. After informed consent adjuvant endocrine therapy, either tamoxifen or an aromatase inhibitor, was prescribed for 5 years. Primary endpoint was ipsilateral breast tumor recurrence (IBTR). Secondary endpoints were contralateral breast cancer, recurrence-free survival (RFS) and overall survival (OS).

Results: Between 2006 and 2012, we included 603 women from 14 Swedish centers. Two patients did not fulfill the inclusion criteria and were excluded from the analysis. Median age was 71 years (range 65 to 90). At a median follow-up of 59 months (range 2 to 110) 13 IBTR (cumulative incidence at five years, 1.3% (95% CI, 0.6% to 2.7%), 4 regional recurrences (one combined with IBTR), 2 distant recurrences both without IBTR or regional recurrence and 11 contralateral breast cancers was observed. Twenty-nine patients were diagnosed with tumors of other origin. Seven of them were endometrial cancers. There were 39 deaths. Only one of the deaths (2.6%) was due to breast cancer and 11 (28.2%) were due to other cancers (2 endometrial cancers). Five-year overall survival was 93.9% (95% CI, 91.4% to 95.7%).

Conclusion: This study demonstrates, with a median follow-up of 59 months, that breast-conserving surgery and endocrine therapy without radiotherapy is a safe treatment option in women with early breast cancer and favorable histopathology aged ≥ 65 years. The risk of IBTR is comparable to the risk of contralateral breast cancer. The low rate of breast cancer deaths indicates that breast cancer mortality is of secondary importance in this subset of women.

Citation Format: Villman KKA, Wickberg Å, Killander F, Lindman H, Bjöhle J, Edlund P, Tennvall-Nittby L, Bachmeier K, Carlberg M, Blomqvist C, Ahlgren J, Liljegren G. Omitting radiotherapy in women ≥ 65 years with early breast cancer and favorable histopathology after breast-conserving surgery, sentinel node biopsy and adjuvant endocrine therapy is safe [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-10-05.

Breast conservation surgery, with and without radiotherapy, in women with lymph node-negative breast cancer: a randomised clinical trial in a population with access to public mammography screening

The effect of postoperative radiotherapy after sector resection for stage I-II lymph node-negative breast cancer was evaluated in a patient population with access to public mammographical screening. 1187 women were randomised to no further treatment or postoperative radiotherapy following a standardised sector resection and axillary dissection. Radiation was administered to a dose of 48-54 Gy. Median age was 60 years, and median size of the detected tumours was 12 mm. Of the women 65% had their tumours detected by mammographical screening. The relative risk (RR) of ipsilateral breast recurrence was significantly higher in the non-irradiated patients compared with the irradiated patients, RR=3.33 (95% Confidence Interval (CI) 2.13-5.19, P<0.001). The corresponding cumulative incidence at 5 years was 14% versus 4%, respectively. Overall survival (OS) was similar, RR=1.16 (95% CI 0.81-1.65, P=0.41), with 5 year probabilities of 93 and 94%, respectively. Recurrence-free survival (RFS) at 5 years was significantly lower in the non-irradiated women, 77% versus 88% (P<0.001). Although women above 49 years of age, whose tumours were detected with mammographical screening, had the lowest rate of ipsilateral breast recurrence in this study, the cumulative incidence of such event amounted to 10% at 5 years if radiotherapy was not given. Such a recurrence rate has been considered as unacceptably high, but is, however, in the same range as that reported after lumpectomy and postoperative radiotherapy in published series.

Arm morbidity after breast-conserving therapy for breast cancer

This study reports on 110 consecutive patients, mean age 59 years, operated on for partial mastectomy and axillary dissection. Radiotherapy of 50 Gy was administered to 75 of the patients. Most tumours were T1 tumours and all patients were NO. Lymphoedema is defined as an increase in arm volume > 10% and impaired shoulder mobility as an impairment of 15 degrees compared with the preoperative value. After operation, 21 patients developed lymphoedema, 17 in the radiotherapy group and 4 in the group without radiotherapy; 49% of the patients had reduced shoulder mobility, and of these, 57% were in the radiotherapy group and 30% in the group without radiotherapy. We found a good correlation between the number of patients stating arm swelling and patients with registered lymphoedema. There were fewer patients stating limitation of movement than patients with registered impaired mobility; 31% of patients were still perceiving some pain five years after the operation. We conclude, that breast-conserving therapy in breast cancer is afflicted with a significant arm morbidity that persists for several years after surgery.

Mastectomy only versus radical mastectomy and postoperative radiotherapy in node negative, resectable breast cancer. A randomized trial

Patients with clinically node negative resectable breast cancer were randomized to either mastectomy only or radical mastectomy and radiotherapy, and followed for 15-20 years. During follow-up axillary metastases occurred with the same frequency after mastectomy as was initially observed in the group that underwent axillary dissection. There was no significant survival difference between the two groups. When adjusting the treatment effect for differences in age, tumour size, lymph node metastases, and histology, the outcome after radical mastectomy plus irradiation was significantly inferior. Comedo carcinoma proved also in this study to carry a poor prognosis.

The total incidence of loco-regional recurrence in a randomized trial of breast cancer TNM stage II. The South Sweden Breast Cancer Trial

We studied loco-regional recurrence during follow-up (median observation time 8 years) in 1,153 patients, who underwent modified mastectomy and were randomly assigned to one of the following postoperative treatments; Premenopausal patients: radiotherapy, cyclophosphamide, or both; Post-menopausal patients: radiotherapy, tamoxifen, or both. Recurrence occurred in a total of 419 patients, 123 of whom had loco-regional recurrence with or without distant metastasis. The loco-regional recurrence rate was 7% in the irradiated subgroups and 17% in the non-irradiated subgroups, the corresponding cure rates being 43% and 58%. Complete remission of all local recurrence was obtained after the first treatment in 67% of the cases, and was persistent in 67% of them (44% overall). Complete remission was obtained in all patients with local recurrence who received local treatment only, and was persistent in 65%. Of local recurrences treated with a combination of surgery, radiotherapy and hormone therapy, complete response was obtained in 94% of the patients, and was persistent in 94% of them (88% overall). Complete remission of all regional recurrence was obtained after the first treatment in 58% of the patients and was persistent in 67% of them (39% overall). Postoperative radiotherapy reduced not only the total number of loco-regional recurrences but also the number of uncontrolled loco-regional recurrences. Aggressive local treatment would appear to yield both satisfactory initial control and, when combined with the hormone therapy, a high rate of persistent loco-regional control.

Modified histologic classification for carcinoma of the breast. Prognostic value and relation to effect of adjuvant oophorectomy

From 1961 to 1966 a series of operable breast cancer patients were included in a prospective study of adjuvant surgical oophorectomy. All histologic slides from 279 patients have been reevaluated and the different tumors classified according to a modified classification system in which invasive ductal carcinoma of comedo type is distinguished from invasive tubuloductal carcinoma. The study demonstrated shorter survival time and recurrence free interval for the comedo category than for the tubuloductal category. It also suggested a beneficial effect of adjuvant oophorectomy in tubuloductal carcinomas but not in comedo carcinomas. The findings support the use of a modified histologic classification for prognostic purposes and suggest a beneficial effect of adjuvant oophorectomy in the treatment of tubuloductal carcinoma of the breast. Further studies concerning adjuvant oophorectomy are needed, especially regarding possible differences in its effect in different histologic categories.