Chemotherapy, molecular targeted therapy, and hormonal therapy are essential components of medical oncology. Al-though cancer patients significantly benefit from the emergence of various new anticancer drugs, none of these treatments can directly address drug resistance. Radiation therapy is one of the three conventional cancer treatment methods. Nearly two-thirds of cancer pa-tients accept radiation therapy during treatment. However, radiation resistance is a significant barrier affecting the therapeutic effect of this procedure. Epithelial–mesenchymal transition (EMT) is a biologic process that enables a polarized epithelial cell to undergo multi-ple biochemical changes. These changes enable the cell to assume the functions of a mesenchymal cell phenotype. These functions have been extensively studied and are related to embryogenesis, tumor invasiveness, and metastasis. In recent years, increasing evidence sug-gests that EMT is closely linked with tumor treatment resistance. The study of the relation between EMT and tumor treatment resistance is expected to contribute to the prevention of drug resistance and radiation resistance and thus improve treatment efficacy to provide benefit to cancer patients. This article explores this issue.

Small cell lung cancer ( SCLC ) is one common type of lung cancer in China. No remarkable progress has been made in systemic therapy for SCLC since the 90’ s. However, there are some advances in radiotherapy ( RT) for SCLC, which make it possible to improve treatment outcomes of SCLC. Those advances are mainly made in thoracic RT and prophylactic cranial irradiation for extensive?stage SCLC, radiation dose and technology of thoracic RT for limited?stage SCLC, and significance of prophylactic cranial irradiation for early?stage SCLC. The paper reviews the research advances in the East and West to provide some help and references for readers.

As a newly identified T helper cell subset, Th9 plays an important role in anti-tumor immunity. Th9 can be differentiated from CD4+T cells that have been induced by TGF-beta and IL-4. In addition, other CD4+T helper cell subsets can be developed to Th9 cell in particular situations, thereby showing its plasticity. Results of animal experiments have indicated that Th9 inhibits tumor growth and plays a significant role in anti-tumor immunity by secreting related cytokines such as IL-9. A few cytokines and molecules can regu-late the differentiation and development of Th9 cells in different signaling pathways. This review will focus on the production, anti-tu-mor immunity, related mechanism, and signaling pathways of Th9 cells, thereby providing a new field of vision and idea for anti-tumor therapy in the future.

Radiotherapy is important for cancer treatment. However, some patients still experience relapse and exhibit radiation resistance. Mammalian target of rapamycin (mTOR) is the main effector molecule in PI3K/AKT signaling. This molecule is found in two structurally and functionally distinct multi-protein complexes known as the mTOR complex 1 and mTOR complex 2. The mTOR signaling pathway controls the growth, proliferation, survival, and apoptosis of cancer cells. This pathway is closely related to tumori-genesis and treatment response, and is used in sensitizing radiotherapy. mTOR inhibitors regulate radio-sensitization through multiple mechanisms, including cell cycle alterations, DNA repair modulation, and tumor hypoxia reduction. Preclinical studies showed that mTOR inhibitors with tolerable toxicity may be used as an effective modality to overcome radio-resistant tumors. Responses to mTOR inhibitors vary depending on the cell lines. Molecular markers can be used to select suitable patients. Further studies are needed to com-pletely understand the use of mTOR inhibitors in radio-sensitization.

As a DNA damage sensor,poly (ADP-ribose) polymerase (PARP) is involved in a wide variety of cellular activities,such as DNA damage repair.PARP inhibitors regulate a series of cellular activities by inhibiting PARP function,which have become a focus of current research.Recently,several in vivo and in vitro studies showed that PARP inhibitors combined with radiotherapy effectively enhanced the efficacy of radiotherapy.This paper reviews the research advances in the mechanisms of action of PARP inhibitors and their combination with radiotherapy.

Objective To investigate the efficacy,toxicity and cosmetic outcome of short-course radiotherapy with concomitant tumor bed boost after breast-conserving surgery for early stage breast cancer.Methods A total of 306 patients with T1-2 N0-1 M0 breast cancer after breast-conserving surgery were included.160 patients received whole-breast radiation to 45 Gy in 25 fractions followed by tumor bed boost of 14 Gy in 7 fractions (C group).146 patients received whole-breast radiation to 46 Gy in 23 fractions with concomitant tumor bed boost to 60 Gy in 23 fractions (S group).Kaplan-Meier method was used to calculate the local recurrence and overall survival rates and the differences were compared by Logrank test.Chi-square test was used to compared the differences of the clinical characteristics,toxicity and cosmetic outcome between the two groups.Results The follow-up rate was 100％.After a median follow up of 26 months,the 1-,2-and 3-year overall survival rates were 100％.No patient developed local recurrence.In C and S group,the incidence of grade 1 acute skin toxicity was 46.9％ and 45.1％ (x2 =0.73,P =0.695),grade 2was 16.3％ and 13.7％ (x2 =0.73,P =0.695).Grade 1 late skin and subcutaneous tissue toxicity developed in 16.9％ and 17.1％ of patients in C and S group (x2 =0.00,P =0.954).Grade 1 neutropenia occurred in 11.9％ and 13.7％ of patients in C and S group (x2 =0.23,P =0.633).In C and S group,66.2％ and 65.5％ of patients had excellent and good cosmetic outcome (x2 =0.01,P =0.927).Conclusions Short-course radiotherapy with concomitant tumor bed boost provides similar results to conventional radiotherapy in local control,toxicity and cosmetic outcome.Long-term follow up is warranted to confirm this finding.

Objective To quantify the incidental irradiation dose (ⅡD) to lymph node stations of esophagus when treating patients with T1-4N0 M0 thoracic esophageal squamous cell carcinoma (ESCC) with a dose of 60 Gy/30f.Methods Twenty-nine patients with medically inoperable T1-4N0M0 thoracic ESCC were treated with three-dimensional radiotherapy on involved-field.The conformal CTV was re-created using a 3 cm margin in the proximal and distal direction (following the course of the esophagus) beyond the barium esophagogram,endoscopic examination and CT defined GTV and a 0.5 cm margin in the lateral and anteroposterior directions of the CT defined GTV.The PTV encompassed 1 cm proximal and distal margins,0.5 cm radiaI margin on the basis of CTV.Cervical,mediastinal and abdominal lymph nodes were delineated respectively.Equivalent uniform dose (EUD) and other dosimetric paraneters were calculated for each nodal station.Nodal region whose metastasis rate is greater than 5％ was considered a high risk lymph node subgroups.Results Under a 60 Gy dose prescription,the median Dmean and EUD,V40 and V50 were ≥40 Gy,≥85％ and ≥75％ in most of the high risk nodal regions.For the subgroups whose EUD were less than 40 Gy,most of the ⅡD of these regions was significantly associated with the length and location of esophageal tumor (r =0.892,P =0.000).Conclusions Lymph node stations nearby of ESCC received considerable ⅡD with involved-field irradiation which could control subclinical lesions.But more clinical studies should be needed.

The current challenge from radiotherapy of early breast cancer has been to minimize the morbidity caused by this treatment without losing efficacy.Conventional two-dimensional radiotherapy breast plans can produce substantial dose inhomogeneities.Intensity-modulated radiotherapy(IMRT) can be used to improve the dose homogeneity in an irradiated volume.And to some extent,IMRT can reduce radiation doses to adjacent normal tissues including the contralateral breast,heart and lung,and improve the cosmetic outcome.

Objective To explore the reasonable radiotherapy range by analyzing the patterns and characteristics of intra-thoracic lymph node metastasis in small cell lung cancer (SCLC).Methods One hundred and fifty patients with limited-stage SCLC who received radical resection of primary tumor and systemic intra-thoracic lymph node dissection were included in the study.All the lymph nodes in each area were recorded and examined pathologically to analyze the patterns and characteristics of intra-thoracic lymph node metastasis.Results A total of 2372 lymph nodes were found in 631 areas,and a total of 413 positive lymph nodes (17.4％) were found in 188 lymph node areas (29.8％ ).Intra-thoracic lymph node metastasis were found in 88 patients,with a positive rate of 58.7％.The frequencies of metastasis in the area 11,10,7,5,4 were much higher than those in the other areas,and central located lesions and the higher T-stage lung tumors were more likely to develop intra-thoracic lymph node metastasis (x2 =15.32,39.72;P =0.000,0.000,respectively).Tumors located in the right upper lobe and right middle/lower lobe had a higher tendency of metastasis to the areas 4,7,10 and 4,7,10,11,respectively.Tumors located in the left upper lobe and left lower lobe had a higher tendency of metastasis to the areas 4,5,6,10 and 4,7,9,10,11,respectively.Mediastinal lymph node metastasis (N2 ) were found in 72 patients,among whom 29 patients (40.3％ ) had skipping N2 metastasis without hilar metastasis.Tumors located in the upper lobe had a tendency of skipping metastasis to the upper mediastinum,while tumors located in the middle/lower lobe had a tendency of skipping metastasis to the upper and lower mediastinum.Conclusions The lymph node metastases in SCLC follow the lymphatic drainage routes,that is,from intrapulmonary to the hilar and then to the mediastinum,but with some skipping metastases.Tumors located in different lobes have different high risk lymph node areas for metastasis,and elective irradiation to these lymph node areas maybe increase radiotherapy gain ratio in SCLC.