Conditional local recurrence risk: the effect of event-free years in different subtypes of breast cancer.

BACKGROUND: After breast cancer treatment, follow-up consists of physical examination and mammography for at least 5 years, to detect local and regional recurrence. The risk of recurrence may decrease after event-free time. This study aims to determine the risk of local recurrence (LR) as a first event until 5 years after diagnosis, conditional on being event-free for 1, 2, 3 and 4 years. METHODS: From the Netherlands Cancer Registry, all M0 breast cancers diagnosed between 2005 and 2008 were included. LR risk was calculated with Kaplan-Meier analysis, overall and for different subtypes. Conditional LR (assuming x event-free years) was determined by selecting event-free patients at x years, and calculating their LR risk within 5 years after diagnosis. RESULTS: Five-year follow-up was available for 34,453 patients. Overall, five-year LR as a first event occurred in 3.0%. This risk varied for different subtypes and was highest for triple negative (6.8%) and lowest for ER+PR+Her2- (2.2%) tumors. After 1, 2, 3 and 4 event-free years, the average risk of LR before 5 years after diagnosis decreased from 3.0 to 2.4, 1.6, 1.0, and 0.6%. The risk decreased in all subtypes, the effect was most pronounced in subtypes with the highest baseline risk (ER-Her2+ and triple negative breast cancer). After three event-free years, LR risk in the next 2 years was 1% or less in all subtypes except triple negative (1.6%). CONCLUSION: The risk of 5-year LR as a first event was low and decreased with the number of event-free years. After three event-free years, the overall risk was 1%. This is reassuring to patients and also suggests that follow-up beyond 3 years may produce low yield of LR, both for individual patients and studies using LR as primary outcome. This can be used as a starting point to tailor follow-up to individual needs.

Women Could Avoid Axillary Lymph Node Dissection by Choosing Breast-Conserving Therapy Instead of Mastectomy.

BACKGROUND: The ACOSOG Z0011 trial showed that completion axillary lymph node dissection (cALND) can be safely omitted for some patients with T1-2 clinically node-negative breast cancer with one to two involved sentinel lymph nodes (SLNs) treated with breast-conserving therapy (BCT). There is little evidence for the safety of omitting cALND for mastectomy-treated patients. Consequently, cALND is often recommended for sentinel node-positive patients treated with mastectomy. The aim of this study is to determine the proportion of patients who could avoid cALND by choosing BCT instead of mastectomy at a tertiary cancer center. PATIENTS AND METHODS: All T1-2 clinically node-negative breast cancer patients treated with BCT or mastectomy between 2012 and 2017 with metastases in the SLN(s) were selected from a prospectively maintained database. Clinical factors and outcomes were evaluated between the two groups. Differences were compared using Wilcoxon rank-sum test, chi-square test or Fisher's exact test as appropriate. Significance was set at the 0.05 level for all analyses. RESULTS: A total of 306 patients were included, 199 (65.0%) of whom were treated with BCT and 107 (35.0%) with mastectomy. Patients treated with mastectomy were more often treated with cALND compared with those treated with BCT (71.0% versus 26.6%, p < 0.0001). Overall, 52 of the mastectomy patients (68.4%) could have avoided cALND if they had chosen BCT. CONCLUSIONS: Patients treated with mastectomy are more likely to receive cALND than those treated with BCT. Axillary management should be addressed during discussion of primary tumor therapy, and cALND may be avoided when patients choose BCT instead of mastectomy.

Extracapsular extension in the positive sentinel lymph node: a marker of poor prognosis in cT1-2N0 breast cancer patients?

OBJECTIVE: This study aims to evaluate whether extracapsular extension (ECE) in the sentinel lymph node (SLN) is associated with involvement of ≥ 4 lymph node metastases at completion axillary lymph node dissection (ALND) and the effect on 5-year disease-free survival (DFS) and 10-year overall survival (OS). ECE in a SLN is usually a contraindication for omitting completion ALND in cT1-2N0 breast cancer patients treated with breast-conserving therapy and 1-2 positive SLN(s). METHODS: All cT1-2N0 breast cancer patients with 1-3 positive SLN(s) who underwent ALND between 2005 and 2008 were selected from the Netherlands Cancer Registry. Logistic regression analysis was used to determine the association between ECE and ≥ 4 lymph node metastases. Five-year DFS and 10-year OS were analyzed using Kaplan-Meier survival analysis. Cox regression analysis was performed to correct for other prognostic factors. RESULTS: A total of 3502 patients were included. Information on ECE was available for 2111 (60.3%) patients, consisting of 741 (35.1%) patients with and 1370 (64.9%) without ECE. The incidence of ≥ 4 lymph node metastases was 116 (15.7%) in the ECE group vs. 80 (5.8%) in the group without ECE (p < 0.001). Five-year DFS rate was 86.4% in the ECE group compared to 88.8% in the group without ECE (p = 0.085). 10-year OS rate was 78.6% compared to 83.0% (p = 0.018), respectively. Cox regression analysis showed that ECE was not an independent prognostic factor for both DFS and OS. CONCLUSIONS: ECE was significantly associated with involvement of ≥ 4 lymph node metastases in the completion ALND group. ECE was not an independent prognostic factor for both DFS and OS.

Conditional regional recurrence risk: The effect of event-free years in different subtypes of breast cancer.

BACKGROUND: Regional recurrence (RR), also known as lymph node recurrence, is an endpoint in several trials concerning reducing axillary treatment in cT1-2N0 breast cancer patients. The risk of RR may decrease with each subsequent event-free year, affecting the yield and consequently usefulness of long (er) follow-up. The aim of this study is to determine the risk of RR as a first event within five years after diagnosis in subtypes of breast cancer, conditional to being event-free for one, two, three and four years. METHODS: From the Netherlands Cancer Registry, cT1-2N0 breast cancer patients diagnosed from 2005 to 2008 were analyzed. Subgroup analysis was performed for pT1-2N+(sn) patients. RR risk was calculated with Kaplan-Meier analysis. Conditional RR (assuming x event-free years) was determined by selecting patients without an event at x years, and calculating the remaining risk for RR within five years after diagnosis. RESULTS: A total of 18,009 cT1-2N0 (all pN stages) breast cancer patients were included. RR occurred in 1.3% of cT1-2N0 and 1.5% of pT1-2N+(sn) patients. The risk of RR varied between subtypes; it was highest for triple negative tumors and lowest for ER + PR + Her2-and ER + Her2+ tumors. After event-free years, the risk of RR decreased subsequently in both groups and in all subtypes. After two event-free years, the risk of RR was 0.8%. CONCLUSION: The absolute yield of follow-up to detect RR beyond two years is low; for every 125 event-free patients, one RR can be expected until five years. This suggests that follow-up longer than two years is of limited value for detecting RR in both clinical and research setting.