Technical innovation in adjuvant radiotherapy: Evolution and evaluation of new treatments for today and tomorrow

Adjuvant endocrine therapy is associated with improved overall survival in elderly hormone receptor-positive breast cancer patients

PURPOSE

There is controversy regarding the survival benefit of endocrine therapy (ET) in elderly patients with early invasive hormone receptor-positive (HR+) breast cancer. In this study, we characterize a single institution's practice patterns using adjuvant ET for these patients and evaluated the effect of ET on outcomes.

METHODS

A review of a prospectively maintained database identified 483 women ≥ 70 years old who underwent breast -conserving surgery (BCS) for stage I-III HR+ tumors from 2004-2013. We compared clinicopathologic characteristics, overall survival (OS), disease-free survival (DFS), locoregional recurrence (LRR), and breast cancer-specific survival (BCSS) in patients who did and did not receive ET.

RESULTS

Compared to patients who did not get ET, patients who received ET were younger (median age 76 vs 78 years, p = 0.006), had larger tumors (median size 15 vs 14 mm, p = 0.016), underwent sentinel lymph node (LN) biopsy (83.7 vs 67.8%, p < 0.001), had positive LNs (25.5 vs 9.8%, p = 0.008), and received radiation (XRT, 76 vs 43%, p < 0.001). After adjusting for ASA score, age, LN status, tumor grade, and XRT, receipt of ET was associated with improved OS (HR 0.44; 95% CI 0.25-0.77; p = 0.004) and DFS (HR 0.42; 95% CI 0.28-0.64; p < 0.01). Receipt of ET was associated with improved LRR on univariate analysis (HR 0.25; 95% CI 0.09-0.70; p = 0.008); however, after adjusting for grade and XRT, this was not statistically significant on multivariable analysis (HR 0.38; 95% CI 0.13-1.08; p = 0.069) and was not associated with BCSS (HR 0.59; 95% CI 0.16-2.16; p = 0.43).

CONCLUSIONS

ET was associated with significant improvements in OS and DFS, regardless of clinicopathological features; however, receipt of ET did not impact LRR and BCSS.

The benefit of adjuvant radiotherapy after breast conserving surgery in older patients with low risk breast cancer- a meta-analysis of randomized trials

PURPOSE/OBJECTIVE(S)

It is currently unclear whether patients with low risk breast cancer receiving adjuvant endocrine therapy need adjuvant radiation therapy after breast conserving surgery. The data of randomized trials are available.

MATERIALS/METHODS

In a database search 5 randomized trials including in total 3766 mostly elderly patients with early stage breast cancer treated either with adjuvant endocrine therapy or with endocrine therapy and additional whole breast radiation after breast conserving surgery were identified. Published hazard ratios for time to local recurrence were the basis of our meta-analysis. Meta-analysis of the effect sizes on local recurrence was performed using a random effects model based on parameter estimates of log hazard ratios in Cox models and their standard errors. Furthermore, overall survival was examined.

RESULTS

Adjuvant hormone therapy alone in mostly older patients with low risk breast cancer resulted in significantly shorter time to local relapse compared to radiation therapy combined with hormone therapy (Hazard Ratio: 6.8, 95% CI: 4.23-10.93, p < 0.0001) . There was no significant difference for overall survival.

CONCLUSION

Additional radiation therapy to hormone therapy did improve local relapse in breast cancer patients but did not show significant impact on overall survival.