Treatment of Internal Mammary Nodes is Associated With Improved Overall Survival in Breast Cancer: A Meta-Analysis.

INTRODUCTION: The role of internal mammary nodal irradiation (IMNI) as a component of regional nodal radiotherapy is a controversial issue in breast radiation oncology with conflicting results presented in recent landmark trials. We thus created a meta-analysis of available data to better ascertain the potential benefit of IMNI. We hypothesize that with the increased power available within a meta-analysis, IMNI will prove to improve overall survival (OS) in breast cancer. METHODS: Literature search was conducted for prospective studies comparing IMNI to no IMNI. Primary endpoint was OS and secondary endpoints included local recurrence, regional recurrence, disease-free survival (DFS), breast cancer mortality (BCM), distant metastasis-free survival (DMFS), grade 2+ skin toxicity, cardiac events, and pneumonitis events. Subgroup analyses were performed for tumor location (medial/central vs. lateral), and nodal status (pN+ vs. pN0). Fixed-effect model was used if there was no heterogeneity, random-effects model otherwise. RESULTS: Four studies with a total of 5258 patients (IMNI: n=2592; control: n=2666) were included in the study. Pooled results showed IMNI significantly improved OS for all-comers (hazard ratio [HR]=0.89; 95% CI 0.81-0.97; P =0.008), as well as subgroups of pN+ with medial/central tumor location (HR=0.84; 95% CI 0.73-0.96; P =0.01) and pN+ with lateral tumor location (HR=0.87; 95% CI 0.77-0.99; P =0.04). There was no significant difference in OS for subgroups of pN0 and medial/central tumor location. There was no difference in local recurrence, but regional recurrence was significantly improved ( P =0.04). Endpoints of DFS (HR 0.91, 95% CI 0.84-0.99 P =0.03), BCM (HR 0.87, 95% CI 0.77-0.98, P =0.03), and DMFS (HR=0.87; 95% CI, 0.78-0.98; P =0.02) were all improved with IMNI. Grade 2+ skin toxicity, cardiac events and pneumonitis events were not significantly different between patient in the IMNI and no IMNI groups. CONCLUSION: Inclusion of IMN irradiation improves OS, DFS, BCM, and DMFS in breast cancer. Largest effect on OS was noted in the subgroup of patients with pN+ and medial/central tumor location.

Consolidation radiotherapy following positron emission tomography complete response in early-stage Hodgkin lymphoma: a meta-analysis.

Despite a number of randomized trials, there is clinical equipoise whether de-escalation with the omission of radiotherapy (RT) in positron emission tomography (PET) responders is safe in early-stage Hodgkin lymphoma (HL). A comprehensive Medline and conference abstracts search was performed to identify prospective studies with the following criteria: early-stage (stage I/II) HL treated with anthracycline-based chemotherapy with PET-directed randomization to ± consolidation RT. Four studies were meta-analyzed with a total of 2267 patients (RT: n = 1136, no RT: n = 1131). Pooled analysis showed a significant progression-free survival (PFS) benefit with RT (HR = 2.08, 95% CI 1.27- 3.43 p = .004, RE). There was no statistically significant overall survival (OS) benefit with RT for all patients (HR = 0.92, 95% CI 0.37-2.30, p = 0.85), nor in favorable (HR = 0.90, p = .89) or unfavorable risk (HR = 1.01, p = .99). In early-stage PET-negative HL, consolidative RT consistently improves PFS across risk stratifications over PET-directed omission of RT, with no significant impact on OS.