Prognostic and predictive impact of stroma cells defned by PDGFRb expression in early breast cancer: results from the randomized SweBCG91RT trial

Purpose Predictive biomarkers are needed to aid the individualization of radiotherapy (RT) in breast cancer. Cancer-associated fibroblasts have been implicated in tumor radioresistance and can be identified by platelet-derived growth factor receptor-beta (PDGFRb). This study aims to analyze how PDGFRb expression affects RT benefit in a large randomized RT trial. Methods PDGFRb was assessed by immunohistochemistry on tissue microarrays from 989 tumors of the SweBCG91RT trial, which enrolled lymph node-negative, stage I/IIA breast cancer patients randomized to RT after breast-conserving surgery. Outcomes were analyzed at 10 years for ipsilateral breast tumor recurrence (IBTR) and any recurrence and 15 years for breast cancer specific death (BCSD). Results PDGFRb expression correlated with estrogen receptor negativity and younger age. An increased risk for any recurrence was noted in univariable analysis for the medium (HR 1.58, CI 95% 1.11–2.23, p = 0.011) or PDGFRb high group (1.49, 1.06–2.10, p = 0.021) compared to the low group. No differences in IBTR or BCSD risk were detected. RT benefit regarding IBTR risk was significant in the PDGFRb low (0.29, 0.12–0.67, p = 0.004) and medium (0.31, 0.16–0.59, p < 0.001) groups but not the PDGFRb high group (0.64, 0.36–1.11, p = 0.110) in multivariable analysis. Likewise, risk reduction for any recurrence was less pronounced in the PDGFRb high group. No significant interaction between RT and PDGFRb-score could be detected. Conclusion A higher PDGFRb-score conferred an increased risk of any recurrence, which partly can be explained by its association with estrogen receptor negativity and young age. Reduced RT benefit was noted among patients with high PDGFRb, however without significant interaction.publishedVersio

Lymph node status after sentinel node biopsy followed by axillary lymph node dissection among breast cancer patients: a population-based study

Background: Axillary lymph node dissection (ALND) for breast cancer patients is performed if there are metastases in sentinel nodes (SNs). However, ALND does not seem to provide a therapeutic benefit for breast cancer patients with few involved SNs and the current literature indicates that patients with 2 positive SNs is unclear. Aim: To quantify the group of luminal A patients with ≥4 LNMs who risk being undertreated with adjuvant chemotherapy and to investigate if the ratio between positive SNs and the total amount of examined SNs can provide additional information of the axillary tumor burden. Material and methods: Patients in Region Västra Götaland with clinically node-negative breast cancer who had undergone sentinel node biopsy (SNB) followed by ALND were analyzed and the SNB findings were compared to the results from the ALND. The potentially undertreated luminal A group was quantified. The ratio of positive to total SNs and its ability to describe the axillary tumor burden was evaluated using Pearson’s chi-square test. Results and conclusion: 16 (17.6%) of the 91 patients with luminal A-like tumors had ≥4 LNMs and 2 of these had >2 positive SNs leaving 14 patients (15.4%) with <3 positive SNs and ≥4 LNMs. The ratio of positive SNs to the total amount of SNs examined was significant in a multivariable analysis for predicting ≥4 LNMs among luminal A-like patients (p=0.027). This was also true for all subtypes combined (p<0.001). Our results indicate that about one sixth of patients with luminal A-like tumors may be undertreated with adjuvant chemotherapy due to a falsely low axillary staging if the indication for ALND is set to >2 positive SN. The SN ratio could be effective at identifying many of these patients

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

Prognostic and predictive impact of stroma cells defned by PDGFRb expression in early breast cancer: results from the randomized SweBCG91RT trial

Purpose Predictive biomarkers are needed to aid the individualization of radiotherapy (RT) in breast cancer. Cancer-associated fibroblasts have been implicated in tumor radioresistance and can be identified by platelet-derived growth factor receptor-beta (PDGFRb). This study aims to analyze how PDGFRb expression affects RT benefit in a large randomized RT trial. Methods PDGFRb was assessed by immunohistochemistry on tissue microarrays from 989 tumors of the SweBCG91RT trial, which enrolled lymph node-negative, stage I/IIA breast cancer patients randomized to RT after breast-conserving surgery. Outcomes were analyzed at 10 years for ipsilateral breast tumor recurrence (IBTR) and any recurrence and 15 years for breast cancer specific death (BCSD). Results PDGFRb expression correlated with estrogen receptor negativity and younger age. An increased risk for any recurrence was noted in univariable analysis for the medium (HR 1.58, CI 95% 1.11–2.23, p = 0.011) or PDGFRb high group (1.49, 1.06–2.10, p = 0.021) compared to the low group. No differences in IBTR or BCSD risk were detected. RT benefit regarding IBTR risk was significant in the PDGFRb low (0.29, 0.12–0.67, p = 0.004) and medium (0.31, 0.16–0.59, p < 0.001) groups but not the PDGFRb high group (0.64, 0.36–1.11, p = 0.110) in multivariable analysis. Likewise, risk reduction for any recurrence was less pronounced in the PDGFRb high group. No significant interaction between RT and PDGFRb-score could be detected. Conclusion A higher PDGFRb-score conferred an increased risk of any recurrence, which partly can be explained by its association with estrogen receptor negativity and young age. Reduced RT benefit was noted among patients with high PDGFRb, however without significant interaction

Effect of Radiotherapy After Breast-Conserving Surgery Depending on the Presence of Tumor-Infiltrating Lymphocytes : A Long-Term Follow-Up of the SweBCG91RT Randomized Trial

PURPOSE: The effects of radiotherapy (RT) on the basis of the presence of stromal tumor infiltrating lymphocytes (TILs) have not been studied. The purpose of this study was to analyze the association of TILs with the effect of postoperative RT on ipsilateral breast tumor recurrence (IBTR) in a large randomized trial. METHODS: In the SweBCT91RT (Swedish Breast Cancer Group 91 Radiotherapy) trial, 1,178 patients with breast cancer stage I and II were randomly assigned to breast-conserving surgery plus postoperative RT or breast-conserving surgery only and followed for a median of 15.2 years. Tumor blocks were retrieved from 1,003 patients. Stromal TILs were assessed on whole-section hematoxylin-eosin-stained slides using a dichotomized cutoff of 10%. Subtypes were scored using immunohistochemistry on tissue microarray. In total, 936 patients were evaluated. RESULTS: Altogether, 670 (71%) of patients had TILs less than 10%. In a multivariable regression analysis with IBTR as dependent variable and RT, TILs, subtype, age, and grade as independent variables, RT (hazard ratio [HR], 0.42; 95% CI, 0.29 to 0.61; P < .001), high TILs (HR, 0.61; 95% CI, 0.39 to 0.96, P = .033) grade (3 v 1; HR, 2.17; 95% CI, 1.08 to 4.34; P = .029), and age (≥ 50 v < 50 years; HR, 0.55; 95% CI, 0.38 to 0.80; P = .002) were predictive of IBTR. RT was significantly beneficial in the low TILs group (HR, 0.37; 95% CI, 0.24 to 0.58; P < .001) but not in the high TILs group (HR, 0.58; 95% CI, 0.28 to 1.19; P = .138). The test for interaction between RT and TILs was not statistically significant (P = .317). CONCLUSION: This study shows that high values of TILs in the primary tumor independently seem to reduce the risk for an IBTR. Our findings further suggest that patients with breast cancer with low TILs may derive a larger benefit from RT regarding the risk of IBTR

Tumour-infiltrating lymphocytes add prognostic information for patients with low-risk DCIS : findings from the SweDCIS randomised radiotherapy trial

BACKGROUND: The immune microenvironment is an important modulator of tumour progression and treatment response. In invasive breast cancer, assessment of tumour-infiltrating lymphocytes (TILs) provides prognostic and predictive information. However, the clinical impact of TILs for ductal carcinoma in situ (DCIS) has not yet been demonstrated. PATIENTS AND METHODS: Post hoc analysis of the SweDCIS randomised radiotherapy trial including primary DCIS cases following breast-conserving surgery. TILs were assessed on haematoxylin-eosin sections (n = 711) according to the International Immuno-Oncology Biomarker Working Group guidelines. TILs-scores were analysed as continuous and dichotomised (≤5% versus &gt;5%) variable regarding ipsilateral breast events (IBEs) as the predefined primary endpoint. RESULTS: Most women (61.9%) showed a TILs prevalence of ≤5%. High TILs-scores were associated with larger lesion size, human epidermal growth factor receptor 2 (HER2)-positivity, higher nuclear grade, and KI67-score. DCIS cases with high TILs prevalence had a significant increased cumulative IBE incidence at five years post-surgery (TILslow-versus TILshigh 9% versus 18%; p &lt; 0.001). Among patients with HER2-negative DCIS, high TILs remained an independent poor prognosis marker for IBE risk in multivariable analysis with an adjusted hazard ratio of 2.41 [95%CI 1.17-4.95, p = 0.017]. Including TILs-status provided a refined stratification of patients with general low-risk DCIS (grade &lt;3, size &lt;25 mm, free margin). No interaction between TILs and radiotherapy benefits was detected. CONCLUSION: High TILs are associated with higher IBE risk over 5-years post-surgery, particularly for HER2-negative DCIS. Our data indicate that TILs should be integrated into the clinical workup to define patients with low-risk DCIS who can omit adjuvant therapy or patients with potential benefits from immunotherapy.De två sista författarna delar sistaförfattarskapet</p

Low levels of WRAP53 predict decreased efficacy of radiotherapy and are prognostic for local recurrence and death from breast cancer: a long‐term follow‐up of the SweBCG91RT randomized trial

Downregulation of the DNA repair protein WD40‐encoding RNA antisense to p53 (WRAP53) has been associated with radiotherapy resistance and reduced cancer survival. The aim of this study was to evaluate WRAP53 protein and RNA levels as prognostic and predictive markers in the SweBCG91RT trial, in which breast cancer patients were randomized for postoperative radiotherapy. Using tissue microarray and microarray‐based gene expression, 965 and 759 tumors were assessed for WRAP53 protein and RNA levels, respectively. Correlation with local recurrence and breast cancer‐related death was assessed for prognosis, and the interaction between WRAP53 and radiotherapy in relation to local recurrence was assessed for radioresistance prediction. Tumors with low WRAP53 protein levels had a higher subhazard ratio (SHR) for local recurrence [1.76 (95% CI 1.10–2.79)] and breast cancer‐related death [1.55 (1.02–2.38)]. Low WRAP53 RNA levels were associated with almost a three‐fold decreased effect of radiotherapy in relation to ipsilateral breast tumor recurrence [IBTR; SHR 0.87 (95% CI 0.44–1.72)] compared with high RNA levels [0.33 (0.19–0.55)], with a significant interaction (P = 0.024). In conclusion, low WRAP53 protein is prognostic for local recurrence and breast cancer‐related death. Low WRAP53 RNA is a potential marker for radioresistance

Immune infiltrate in the primary tumor predicts effect of adjuvant radiotherapy in breast cancer : Results from the randomized SweBCG91RT trial

Purpose: Tumor-infiltrating immune cells play a key role in tumor progression. The purpose of this study was to analyze whether the immune infiltrate predicts benefit from postoperative radiotherapy in a large randomized breast cancer radiotherapy trial. Experimental Design: In the SweBCG91RT trial, patients with stage I and II breast cancer were randomized to breast-conserving surgery (BCS) and postoperative radiotherapy or to BCS only and followed for a median time of 15.2 years. The primary tumor immune infiltrate was quantified through two independent methods: IHC and gene expression profiling. For IHC analyses, the absolute stromal area occupied by CD8þ T cells and FOXP3þ T cells, respectively, was used to define the immune infiltrate. For gene expression analyses, immune cells found to be prognostic in independent datasets were pooled into two groups consisting of antitumoral and protumoral immune cells, respectively. Results: An antitumoral immune response in the primary tumor was associated with a reduced risk of breast cancer recurrence and predicted less benefit from adjuvant radiotherapy. The interaction between radiotherapy and immune phenotype was significant for any recurrence in both the IHC and gene expression analyses (P ¼ 0.039 and P ¼ 0.035) and was also significant for ipsilateral breast tumor recurrence in the gene expression analyses (P ¼ 0.025). Conclusions: Patients with an antitumoral immune infiltrate in the primary tumor have a reduced risk of any recurrence and may derive less benefit from adjuvant radiotherapy. These results may impact decisions regarding postoperative radiotherapy in early breast cancer

Supplementary Figure S1 from Integrating Tumor-Intrinsic and Immunologic Factors to Identify Immunogenic Breast Cancers from a Low-Risk Cohort: Results from the Randomized SweBCG91RT Trial

Gene sets from the molecular signatures database were used to create a model measuring immunological activity and immunomodulatory tumor-intrinsic factors. These were merged to create a model considering the interaction between the antitumoral immune response and tumor-intrinsic immunomodulatory factors.</p

Supplementary Figure S5 from Integrating Tumor-Intrinsic and Immunologic Factors to Identify Immunogenic Breast Cancers from a Low-Risk Cohort: Results from the Randomized SweBCG91RT Trial

Ki67 was evaluated by a board-certified pathologist on TMAs.  </p