In this study, we aimed to evaluate the anticancer effect of benzimidazole derivatives on triple-negative breast cancer (TNBC) and investigate its underlying mechanism of action. Several types of cancer and normal breast cells including MDA-MB-231, radiotherapy-resistant (RT-R) MDA-MB-231, and allograft mice were treated with six benzimidazole derivatives including mebendazole (MBZ). Cells were analyzed for viability, colony formation, scratch wound healing, Matrigel invasion, cell cycle, tubulin polymerization, and protein expression by using Western blotting. In mice, liver and kidney toxicity, changes in body weight and tumor volume, and incidence of lung metastasis were analyzed. Our study showed that MBZ significantly induced DNA damage, cell cycle arrest, and downregulation of cancer stem cell markers CD44 and OCT3/4, and cancer progression-related ESM-1 protein expression in TNBC and RT-R-TNBC cells. In conclusion, MBZ has the potential to be an effective anticancer agent that can overcome treatment resistance in TNBC.

Local radiotherapy (RT) is important to manage metastatic triple-negative breast cancer (TNBC). Although RT primarily reduces cancer cells locally, this control can be enhanced by triggering the immune system via immunotherapy. RT and immunotherapy may lead to an improved systemic effect, known as the abscopal effect. Here, we analyzed the antitumor effect of combination therapy using RT with an anti-programmed cell death-1 (PD-1) antibody in primary tumors, using poorly immunogenic metastatic mouse mammary carcinoma 4T1 model. Mice were injected subcutaneously into both flanks with 4T1 cells, and treatment was initiated 12 days later. Mice were randomly assigned to three treatment groups: (1) control (no treatment with RT or immune checkpoint inhibitor (ICI)), (2) RT alone, and (3) RT+ICI. The same RT dose was prescribed in both RT-alone and RT+ICI groups as 10Gy/fx in two fractions and delivered to only one of the two tumor burdens injected at both sides of flanks. In the RT+ICI group, 200 µg fixed dose of PD-1 antibody was intraperitoneally administered concurrently with RT. The RT and ICI combination markedly reduced tumor cell growth not only in the irradiated site but also in non-irradiated sites, a typical characteristic of the abscopal effect. This was observed only in radiation-sensitive cancer cells. Lung metastasis development was lower in RT-irradiated groups (RT-only and RT+ICI groups) than in the non-irradiated group, regardless of the radiation sensitivity of tumor cells. However, there was no additive effect of ICI on RT to control lung metastasis, as was already known regarding the abscopal effect. The combination of local RT with anti-PD-1 blockade could be a promising treatment strategy against metastatic TNBC. Further research is required to integrate our results into a clinical setting.

The eighth tumor, node, metastasis (TNM) staging system (8-TNM) for non-small cell lung cancer (NSCLC) was newly released in 2015. This system had limitation because most patients included in the analysis were treated with surgery. Therefore, it might be difficult to reflect prognosis of patients treated with curative concurrent chemoradiotherapy (CCRT). Purpose of this study was to investigate clinical impact of the newly published 8-TNM compared to the current seventh TNM staging system (7-TNM) for locally advanced NSCLC patients treated with CCRT. New 8-TNM was applied to 64 patients with locally advanced NSCLC who were treated with CCRT from 2010 to 2015. Changes in T category and stage group by 8-TNM were recorded and patterns of change were evaluated. Survival was analyzed according to T category, N category, and stage group in each staging system, respectively. Among the total of 64 patients, 38 (59.4%) patients showed change in T category while 22 (34.4%) patients showed change in stage group using 8-TNM compared to 7-TNM. Survival curves were significantly separated in the 8-TNM stage group (p = 0.001) than those in the 7-TNM (p > 0.05). Especially, survival of newly introduced stage IIIC by 8-TNM was significantly lower than that of others. On the other hand, there was no significant survival difference between T categories in each staging system. Subdivision of stage III into IIIA, IIIB, and IIIC by 8-TNM for patients treated with CCRT better reflected prognosis than 7-TNM. However, subdivision of T category according to tumor size in 8-TNM might be less significant.

Incurable inflammatory breast cancer (IBC) patients occasionally suffer from general symptoms such as breast pain, bleeding, ulceration, and discharge, and thus require palliative radiotherapy (RT). Hypofractionated RT has many advantages in palliative settings, but very few studies on IBC have been conducted. This study was conducted to evaluate the effects of hypofractionated RT on symptomatic IBC patients. Twenty-two patients with IBC who underwent hypofractionated palliative RT between 2010 and 2016 were retrospectively analyzed. RT was performed at a total dose of 42.5–55 Gy with 2.5–3 Gy per fraction. The treatment effects were evaluated with respect to symptom improvement, tumor response, and treatment-related toxicity. The main symptoms that the patients complained of before RT were pain, bleeding, and discharge. According to the percentage of symptom relief compared with pre-RT symptoms, the number of patients with < 30, 30–70%, and ≥ 70% were 2 (9.1%), 7 (31.8%), and 13 (59.1%), respectively. Eighteen (81.8%) patients showed tumor response. No patient experienced grade 3 or higher acute or chronic toxicity during a median follow-up period of 13 months. In univariate analysis, symptom type was a significant factor for predicting the degree of symptom relief. Meanwhile, RT field and C-reactive protein increase were significant factors for predicting the incidence of radiation-induced skin toxicity. Hypofractionated RT could safely and effectively relieve symptoms among incurable symptomatic IBC patients.

The role of adjuvant radiotherapy (RT) and setting proper RT target volumes have not been clearly demonstrated for extrahepatic bile duct (EHBD) cancer, due to the rarity of the disease and the lack of randomized trials. This study was conducted to evaluate the indication and treatment volume for adjuvant RT in EHBD cancer patients by identifying the prognostic factors for loco-regional (LR) failure, and analyze the patterns of LR failure. Ninety-three patients with EHBD cancer, who underwent resection without adjuvant RT, at 2 medical centers, between 2001 and 2016, were analyzed retrospectively. Univariable and multivariable analyses were performed to find the prognostic factors for LR recurrence. The initial patterns of failure were recorded, especially those of LR recurrence, and categorized according to the Japanese classification. The median follow-up duration was 30 months, and 38 (40.9%) patients experienced LR recurrence during this period. With regards to LR recurrence, close or positive resection margin (RM) status (p < 0.001) remained statistically significant in the multivariable analysis. The most common LR recurrence sites were the tumor bed (18.3%), and lymph node (LN) stations No. 8 (14.1%), No. 9 (12.7%), No. 12 (12.7%), No. 13 (5.6%), No. 14 (21.1%), No. 16 (14.1%), and No. 17 (1.4%). A close or positive RM status may be suggestive of high LR recurrence rates. In such cases, adjuvant RT may improve outcomes. When adjuvant RT is performed, the treatment volume should be well-designed so as to encompass the tumor bed, as well as LN stations No. 8, No. 9, No. 12, No. 14, and No. 16.