Association of the tissue infiltrated and peripheral blood immune cell subsets with response to radiotherapy for rectal cancer

Mitochondrial function changes in T cell subsets during radiotherapy for patients with nasopharyngeal carcinoma

Mitochondrial dysfunction-mediated T cell exhaustion is associated with the efficacy of tumor therapy; however, the effect of radiotherapy (RT) on the mitochondrial function of peripheral blood immune cells remains still unclear. Therefore, the current study aimed to determine mitochondrial function indicators in immune cells, in particular mitochondrial mass (MM) and mitochondrial membrane potential (MMP), to assess the dynamic changes of immune status in patients with nasopharyngeal carcinoma (NPC) during RT. Peripheral venous blood was collected from patients with locally advanced NPC at day 1 pre-RT, at the 10th fraction of RT and within 2 days after RT. Based on a novel immunofluorescence technique, flow cytometry was used to assess the proportion of lymphocytes and their subsets in peripheral blood and the mitochondrial indexes, MM and low MMP (MMPlow). Univariate and multivariate logistic regression analyses were performed to evaluate the clinical factors associated with the efficacy of RT. A total of 27 patients were enrolled. After RT, lymphocyte count (P<0.05) and the proportion of CD4+ T cells (P<0.05) demonstrated a downward trend. In addition, the proportion of CD4+ memory-effector T (Tem; P<0.05) cells and CD8+ Tem cells (P=0.005) significantly increased during RT. No significant changes were demonstrated for MM in CD4+ effector T (Te) cells, whilst MMPlow was significantly reduced (P=0.047). However, the mitochondrial function of CD8+ T cells did not significantly change. Multivariate logistic regression analysis revealed that lymphocyte count [odds ratio (OR), 47.317; 95% confidence interval (CI), 1.240-1806.065] and MMPlow in CD4+ Te cells (OR, 0.889; 95% CI, 0.792-0.997) were independent factors that could affect clinical efficacy. Receiver operating characteristic curve analysis demonstrated that the area under the curve values for MMPlow in CD4+ T cells, lymphocyte count and their combination were 0.72 (P=0.13), 0.69 (P=0.19) and 0.89 (P=0.0073), respectively. These findings suggest that RT could inhibit immune cells in peripheral blood. However, this treatment approach could activate the memory cell subsets of immune cells and enhance the MMP of effector CD4+ T cells. Therefore, the evaluation of mitochondrial function in lymphocytes could be used as a predictor of RT efficacy in patients with locally advanced NPC.

Radiation drives tertiary lymphoid structures to reshape TME for synergized antitumour immunity

Radiotherapy (RT) plays a key role in the tumour microenvironment (TME), impacting the immune response via cellular and humoral immunity. RT can induce local immunity to modify the TME. It can stimulate dendritic cell maturation and T-cell infiltration. Moreover, B cells, macrophages and other immune cells may also be affected. Tertiary lymphoid structure (TLS) is a unique structure within the TME and a class of aggregates containing T cells, B cells and other immune cells. The maturation of TLS is determined by the presence of mature dendritic cells, the density of TLS is determined by the number of immune cells. TLS maturation and density both affect the antitumour immune response in the TME. This review summarized the recent research on the impact and the role of RT on TLS, including the changes of TLS components and formation conditions and the mechanism of how RT affects TLS and transforms the TME. RT may promote TLS maturation and density to modify the TME regarding enhanced antitumour immunity.

Peripheral lymphocyte count as an indicator of radiotherapy effectiveness in hypopharyngeal squamous cell carcinoma

OBJECTIVES

To explore the predictive significance of baseline absolute peripheral lymphocyte counts (ALC) in the effectiveness of radiation in hypopharyngeal squamous cell carcinoma (HPSCC) patients.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective study of pathologically confirmed HPSCC patients who had definitive radiation between January 2020 and January 2022 at Fudan University Eye and ENT Hospital. The routine blood results of patients were obtained to determine if the baseline ALC was connected with the response to radiation. The receiver operator characteristic (ROC) curve and LASSO-based Cox regression were employed to assess the predictive value of ALC for the efficacy of radiotherapy (RT).

MAIN OUTCOME MEASURES AND RESULTS

RT induced a considerable drop in ALC and the level of ALC did not revert to the baseline values 1 year after radiation. The baseline level of ALC was higher in patients who met complete response after RT. The baseline ALC and monocyte counts demonstrated the predictive value of radiation effectiveness and ALC was an independent predictor.

CONCLUSION

In HPSCC, lymphocytes were sensitive to radiation and reduced significantly during RT. The baseline ALC might be regarded as a predictive indicator of the effectiveness of RT.

Neoadjuvant chemoradiotherapy combined with sequential perioperative toripalimab in locally advanced esophageal squamous cell cancer

BACKGROUND

Programmed death 1 (PD-1) inhibitor demonstrated durable antitumor activity in advanced esophageal squamous cell carcinoma (ESCC), but the clinical benefit of perioperative immunotherapy in ESCC remains unclear. This study evaluated the efficacy and safety of neoadjuvant chemoradiotherapy (nCRT) combined with the PD-1 inhibitor toripalimab in patients with resectable ESCC.

METHODS

From July 2020 to July 2022, 21 patients with histopathologically confirmed thoracic ESCC and clinical staged as cT1-4aN1-2M0/cT3-4aN0M0 were enrolled. Eligible patients received radiotherapy (23 fractions of 1.8 Gy, 5 fractions a week) with concurrent chemotherapy of paclitaxel/cisplatin (paclitaxel 45 mg/m2 and cisplatin 25 mg/m2) on days 1, 8, 15, 22, 29 and two cycles of toripalimab 240 mg every 3 weeks after nCRT for neoadjuvant therapy before surgery, four cycles of toripalimab 240 mg every 3 weeks for adjuvant therapy after surgery. The primary endpoint was the major pathological response (MPR) rate. The secondary endpoints were safety and survival outcomes.

RESULTS

A total of 21 patients were included, of whom 20 patients underwent surgery, 1 patient refused surgery and another patient was confirmed adenocarcinoma after surgery. The MPR and pathological complete response (pCR) rates were 78.9% (15/19) and 47.4% (9/19) for surgery ESCC patients. 21 patients (100.0%) had any-grade treatment-related adverse events, with the most common being lymphopenia (100.0%), leukopenia (85.7%), neutropenia (52.4%). 14 patients (66.7%) had adverse events of grade 3 with the most common being lymphopenia (66.7%). The maximum standardized uptake value and total lesion glycolysis of positron emission tomography/CT after neoadjuvant therapy well predicted the pathological response. The peripheral CD4+%, CD3+HLA-DR+/CD3+%, CD8+HLA-DR+/CD8+%, and IL-6 were significant differences between pCR and non-pCR groups at different times during neoadjuvant therapy. Three patients had tumor relapse and patients with MPR have longer disease-free survival than non-MPR patients.

CONCLUSIONS

nCRT combined with perioperative toripalimab is effective and safe for locally advanced resectable ESCC. Long-term survival outcomes remain to be determined.

TRIAL REGISTRATION NUMBER

NCT04437212.

A multi-class classification algorithm based on hematoxylin-eosin staining for neoadjuvant therapy in rectal cancer: a retrospective study

Neoadjuvant therapy (NAT) is a major treatment option for locally advanced rectal cancer. With recent advancement of machine/deep learning algorithms, predicting the treatment response of NAT has become possible using radiological and/or pathological images. However, programs reported thus far are limited to binary classifications, and they can only distinguish the pathological complete response (pCR). In the clinical setting, the pathological NAT responses are classified as four classes: (TRG0-3), with 0 as pCR, 1 as moderate response, 2 as minimal response and 3 as poor response. Therefore, the actual clinical need for risk stratification remains unmet. By using ResNet (Residual Neural Network), we developed a multi-class classifier based on Hematoxylin-Eosin (HE) images to divide the response to three groups (TRG0, TRG1/2, and TRG3). Overall, the model achieved the AUC 0.97 at 40× magnification and AUC 0.89 at 10× magnification. For TRG0, the model under 40× magnification achieved a precision of 0.67, a sensitivity of 0.67, and a specificity of 0.95. For TRG1/2, a precision of 0.92, a sensitivity of 0.86, and a specificity of 0.89 were achieved. For TRG3, the model obtained a precision of 0.71, a sensitivity of 0.83, and a specificity of 0.88. To find the relationship between the treatment response and pathological images, we constructed a visual heat map of tiles using Class Activation Mapping (CAM). Notably, we found that tumor nuclei and tumor-infiltrating lymphocytes appeared to be potential features of the algorithm. Taken together, this multi-class classifier represents the first of its kind to predict different NAT responses in rectal cancer.

Immune Response and Immune Checkpoint Molecules in Patients with Rectal Cancer Undergoing Neoadjuvant Chemoradiotherapy: A Review

It is well-established that tumor antigens and molecules expressed and secreted by cancer cells trigger innate and adaptive immune responses. These two types of anti-tumor immunity lead to the infiltration of the tumor's microenvironment by immune cells with either regulatory or cytotoxic properties. Whether this response is associated with tumor eradication after radiotherapy and chemotherapy or regrowth has been a matter of extensive research through the years, mainly focusing on tumor-infiltrating lymphocytes and monocytes and their subtypes, and the expression of immune checkpoint and other immune-related molecules by both immune and cancer cells in the tumor microenvironment. A literature search has been conducted on studies dealing with the immune response in patients with rectal cancer treated with neoadjuvant radiotherapy or chemoradiotherapy, assessing its impact on locoregional control and survival and underlying the potential role of immunotherapy in the treatment of this cancer subtype. Here, we provide an overview of the interactions between local/systemic anti-tumor immunity, cancer-related immune checkpoint, and other immunological pathways and radiotherapy, and how these affect the prognosis of rectal cancer patients. Chemoradiotherapy induces critical immunological changes in the tumor microenvironment and cancer cells that can be exploited for therapeutic interventions in rectal cancer.