Combining histological grade, TILs, and the PD-1/PD-L1 pathway to identify immunogenic tumors and de-escalate radiotherapy in early breast cancer: a secondary analysis of a randomized clinical trial

BACKGROUND

The implementation of immunological biomarkers for radiotherapy (RT) individualization in breast cancer requires consideration of tumor-intrinsic factors. This study aimed to investigate whether the integration of histological grade, tumor-infiltrating lymphocytes (TILs), programmed cell death protein-1 (PD-1), and programmed death ligand-1 (PD-L1) can identify tumors with aggressive characteristics that can be downgraded regarding the need for RT.

METHODS

The SweBCG91RT trial included 1178 patients with stage I-IIA breast cancer, randomized to breast-conserving surgery with or without adjuvant RT, and followed for a median time of 15.2 years. Immunohistochemical analyses of TILs, PD-1, and PD-L1 were performed. An activated immune response was defined as stromal TILs ≥10% and PD-1 and/or PD-L1 expression in ≥1% of lymphocytes. Tumors were categorized as high-risk or low-risk using assessments of histological grade and proliferation as measured by gene expression. The risk of ipsilateral breast tumor recurrence (IBTR) and benefit of RT were then analyzed with 10 years follow-up based on the integration of immune activation and tumor-intrinsic risk group.

RESULTS

Among high-risk tumors, an activated immune infiltrate was associated with a reduced risk of IBTR (HR 0.34, 95% CI 0.16 to 0.73, p=0.006). The incidence of IBTR in this group was 12.1% (5.6-25.0) without RT and 4.4% (1.1-16.3) with RT. In contrast, the incidence of IBTR in the high-risk group without an activated immune infiltrate was 29.6% (21.4-40.2) without RT and 12.8% (6.6-23.9) with RT. Among low-risk tumors, no evidence of a favorable prognostic effect of an activated immune infiltrate was seen (HR 2.0, 95% CI 0.87 to 4.6, p=0.100).

CONCLUSIONS

Integrating histological grade and immunological biomarkers can identify tumors with aggressive characteristics but a low risk of IBTR despite a lack of RT boost and systemic therapy. Among high-risk tumors, the risk reduction of IBTR conferred by an activated immune infiltrate is comparable to treatment with RT. These findings may apply to cohorts dominated by estrogen receptor-positive tumors.

Molecular profile-based recommendations for postoperative adjuvant therapy in early endometrial cancer with high-intermediate or intermediate risk: a Chinese randomized phase III trial (PROBEAT)

BACKGROUND

The use of molecular categorisation is shifting paradigm towards the use of molecular information to refine risk stratification in endometrial cancer (EC). To date, evidence to support molecular-guided therapies is limited to retrospective studies and secondary molecular analyses of patients receiving standard treatment. The PROBEAT study is the first randomized phase III trial to evaluate tailored adjuvant treatment based on WHO-endorsed molecular classification in Chinese EC patients. It is expected to provide a clinical decision-making tool for adjuvant treatment of patients with high-intermediate risk (HIR) or intermediate risk (IR) EC to better optimise and personalise patient care and increase relapse-free survival.

METHODS

The PROBEAT trial is a prospective, multicentre study led by Women's Hospital of Zhejiang University Gynaecologic Oncology Group. Recruitment started on January 24, 2022, and 590 patients with HIR or IR endometrioid EC are expected to be recruited from 13 clinical centres in China. All tumor tissues will be classified into four molecular subtypes (POLEmut, MMRd, p53abn, or NSMP) based on WHO-endorsed molecular classification. Patients will be randomly assigned at a 2:1 ratio to either experimental arm and will receive molecular profile-based adjuvant treatment (observation in the POLEmut subgroup, vaginal brachytherapy in the MMRd or NSMP subgroup, or chemoradiotherapy in the p53abn subgroup) or to standard arm and will receive preferred adjuvant radiotherapy as recommended by the recent National Comprehensive Cancer Network guidelines version 1 (2022). The primary outcome is 3-year rates of recurrence. Secondary outcomes are relapse-free survival, overall survival, adverse events and health-related cancer-specific quality of life.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05179447.

First-line nivolumab plus ipilimumab for metastatic non-small cell lung cancer, including patients with ECOG performance status 2 and other special populations: CheckMate 817

BACKGROUND

CheckMate 817, a phase 3B study, evaluated flat-dose nivolumab plus weight-based ipilimumab in patients with metastatic non-small cell lung cancer (NSCLC). Here, in this research, we report on first-line treatment in patients with Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0-1 (cohort A) and special populations (cohort A1: ECOG PS 2; or ECOG PS 0-1 with untreated brain metastases, renal impairment, hepatic impairment, or controlled HIV infection).

METHODS

Cohorts A and A1 received nivolumab 240 mg every 2 weeks plus ipilimumab 1 mg/kg every 6 weeks. The primary endpoint was the incidence of grade 3-4 and grade 5 immune-mediated adverse events (IMAEs; adverse events (AEs) deemed potentially immune-related, occurring <100 days of last dose, and treated with immune-modulating medication (except endocrine events)) and treatment-related select AEs (treatment-related AEs with potential immunological etiology requiring frequent monitoring/intervention, reported between first dose and 30 days after the last dose) in cohort A; efficacy endpoints were secondary/exploratory. In cohort A1, safety/efficacy assessment was exploratory.

RESULTS

The most common grade 3-4 IMAEs were pneumonitis (5.1%), diarrhea/colitis (4.9%), and hepatitis (4.6%) in cohort A (N=391) and diarrhea/colitis (3.5%), hepatitis (3.5%), and rash (3.0%) in cohort A1 (N=198). The most common grade 3-4 treatment-related select AEs were hepatic (5.9%), gastrointestinal (4.9%), and pulmonary (4.6%) events in cohort A and gastrointestinal (4.0%), skin (3.5%), and endocrine (3.0%) events in cohort A1. No grade 5 IMAEs or treatment-related select AEs occurred. Treatment-related deaths occurred in 4 (1.0%) and 3 (1.5%) patients in cohorts A and A1, respectively. Three-year overall survival (OS) rates were 33.7% and 20.5%, respectively.

CONCLUSIONS

Flat-dose nivolumab plus weight-based ipilimumab was associated with manageable safety and durable efficacy in cohort A, consistent with data from phase 3 metastatic NSCLC studies. Special populations of cohort A1 including patients with ECOG PS 2 or ECOG PS 0-1 with untreated brain metastases had manageable treatment-related toxicity and clinically meaningful 3-year OS rate.

TRIAL REGISTRATION NUMBER

NCT02869789.