The Prognostic Value Of Radiation-induced Lymphopenia And Tumor-infiltrating Lymphocytes In Patients With Breast Cancer

Part Ⅰ:Postmastectomy radiation-induced lymphopenia predicts poorer prognosis in patients with breast cancerPurpose:Hypofractionated radiotherapy(HFRT)in now widely used for treatment of breast cancer,but whether it decreases the risk of radiation-induced lymphopenia(RIL)is not yet known.The aim of this study was to determine if radiation fractionation affected RIL and if RIL affects survival of patients with breast cancer.Methods and materials:Post-hoc analysis was conducted on data from 598 patients with breast cancer from a randomized controlled trial comparing postmastectomy HFRT(43.5 Gy in 15 fractions over 3 weeks)with conventional fractionated radiotherapy(CFRT;50 Gy in 25 fractions over 5 weeks).Mean peripheral lymphocyte count(PLC)at different time points in the two groups was compared by the t-test.Disease-free survival(DFS)and overall survival(OS)were analyzed by the Kaplan-Meier method and compared between groups by the log-rank test.Results:Baseline PLC(pre-PLC)was comparable between HFRT and CFRT patients(1.60 ± 0.57 × 109/L vs.1.56 ± 0.52 × 109/L;P=.33).In both groups,the PLC declined steadily during the course of radiotherapy but started to recover at 1 month after radiotherapy.Incidence of lymphopenia was significantly lower in HFRT patients(45.4%vs.55.7%;P=.01).Nadir PLC(nadir-PLC)was significantly higher in HFRT patients(1.08 ± 0.37 × 109/L vs.0.97 ± 0.31 109/L;P<.001),as also the nadir-PLC/pre-PLC ratio(0.72± 0.28 vs.0.67± 0.28;P=.02).Median follow-up was for 57.6 months(interquartile range,38.5-81.4).The 5-year DFS was significantly lower in patients with nadir-PLC/pre-PLC ratio<0.8 than in those with ratio≥0.8(71.8%vs.82.6%;P.01);however,OS was comparable between the groups(85.8%vs.90.6%;P=.24).Conclusions:The risk of RIL in breast cancer patients is lower with HFRT than with CFRT.Low nadir-PLC/pre-PLC ratio may predict poor prognosis.Part Ⅱ:Tumor-infiltrating lymphocytes and prognosis in stage I-III triple-negative breast cancerPurpose:To investigate the prognostic value of tumor-infiltrating lymphocytes(TIL)in patients with triple-negative breast cancer(TNBC).Methods and materials:The clinicopathologic data of 259 patients with Ⅰ-Ⅲ stage TNBC treated in one institution from 2010 to 2013 were collected.Two-hundred and thirteen patients(82.2%)received mastectomy and 46(17.8%)received breast-conserving surgery.All had received adjuvant chemotherapy without neoadjuvant therapy,and 96(37.1%)received postoperative radiotherapy.The density of TILs with its expression of stromal(s)and intratumoral(i)CD8+T lymphocyte,FOXP3+T lymphocyte(sCD8+T,iCD8+T,sFOXP3+T,iFOXP3+T)were evaluated by haematoxylin and eosin and immunohistochemical(IHC)staining.An IHC staining for PD-1 and PD-L1(22C3)were also conducted.Locoregional recurrence(LRR),distant metastasis(DM),disease-free survival(DFS)and overall survival(OS)rates were calculated by using the Kaplan-Meier method and compared by log-rank test.The association of relapse and survival outcomes with TIL and PD-1/PD-L1 concentration was evaluated using multivariable proportional hazards regression.Optimum cutoff values for sCD8+T,iCD8+T,sFOXP3+T and iFOXP3+T were identified using the maxstat package in R.Results:At a median follow-up of 80 months(range,9-111 months),patients with high sTIL(≥60%)had significantly lower 5-year LRR(5.3%vs 14.6%;p=0.047)and higher DFS(94.7%vs 84.5%;p=0.025)compared to those with low sTIL(<60%).Patients with high sCD8+T(>10%)had significantly lower 5-year LRR(5.6%vs 15.6%,p=0.022)and DM(4.2%vs 14.6%;p=015)and higher 5-year DFS(94.4%vs 83.9%,p=0.031)compared to patients with low sCD8+T(≤10%).Patients with high iCD8+T(>5%)had significantly lower 5-year LRR(2.2%vs 14.7%,p=0.011)and DM(2.2%vs 14.7%,p=0.019)and higher 5-year DFS(97.8%vs 84.4%,p=0.007)and OS(97.7 vs 91.2%,p=0.026)compared to patients with low iCD8+T(≤5%).Patients with high sFOXP3+T(>3/HPF)also had significantly lower 5-year LRR(4.5%vs 15.5%,p=0.001)and DM(4.3%vs 14.0%,p=0.043)and higher 5-year DFS(94.2%vs 84.6%,p=0.034)and OS(95.6%vs 91.0%,p=0.039)compared to low sFOXP3+T(≤3/HPF).However,no survival benefits were found from patients with high iFOXP3+T(>14/HPF).Presence of PD-1-positive immune cells(≥1%)in TNBC were associated with a significantly better DFS(93.4%vs 83.5%,p=0.044)，while PD-L1 expression had no impact on patient outcomes.Multivariate analysis revealed that sTIL(HR 0.22,95%CI 0.05-0.97,p=0.045)and PD-1(HR 0.40,95%CI:0.16-0.97,p=0.044)were independent prognostic factors for DFS,in addition to stage and lymphovascular invasion.No other subsets of TIL nor PD-L1 was independently associated with relapse or survival(all p>0.05).Conclusions:High density of stromal TIL and presence of PD-1-positive immune cells may have a positive prognostic value in TNBC.These findings need futher validation.