Immunotherapy that boosts the body's immune system to treat local and distant metastatic tumors has offered a new treatment option for cancer. However, cancer immunotherapy via systemic administration of immunotherapeutic agents often has two major issues of limited immune responses and potential immune-related adverse events in the clinic. Hydrogels, a class of three-dimensional network biomaterials with unique porous structures can achieve local delivery of drugs into tumors to trigger the antitumor immunity, resulting in amplified immunotherapy at lower dosages. In this review, we summarize the recent development of polymer-based hydrogels as drug release systems for local delivery of various immunotherapeutic agents for cancer immunotherapy. The constructions of polymer-based hydrogels and their local delivery of various drugs in tumors to achieve sole immunotherapy, and chemotherapy-, and phototherapy-combinational immunotherapy are introduced. Furthermore, a brief conclusion is given and existing challenges and further perspectives of polymer-based hydrogels for cancer immunotherapy are discussed.

Background: Chest CT is used for the assessment of the severity of patients infected with novel coronavirus 2019 (COVID-19). We collected chest CT scans of 202 patients diagnosed with the COVID-19, and try to develop a rapid, accurate and automatic tool for severity screening follow-up therapeutic treatment.Methods: A total of 729 2D axial plan slices with 246 severe cases and 483 non-severe cases were employed in this study. By taking the advantages of the pre-trained deep neural network, four pre-trained off-the-shelf deep models (Inception-V3, ResNet-50, ResNet-101, DenseNet-201) were exploited to extract the features from these CT scans. These features are then fed to multiple classifiers (linear discriminant, linear SVM, cubic SVM, KNN and Adaboost decision tree) to identify the severe and non-severe COVID-19 cases. Three validation strategies (holdout validation, tenfold cross-validation and leave-one-out) are employed to validate the feasibility of proposed pipelines.Results and conclusion: The experimental results demonstrate that classification of the features from pre-trained deep models shows the promising application in COVID-19 severity screening, whereas the DenseNet-201 with cubic SVM model achieved the best performance. Specifically, it achieved the highest severity classification accuracy of 95.20% and 95.34% for tenfold cross-validation and leave-one-out, respectively. The established pipeline was able to achieve a rapid and accurate identification of the severity of COVID-19. This may assist the physicians to make more efficient and reliable decisions.

For the recurrence of head and neck cancer after operation and radiotherapy, the local control of radioactive seed implantation is good, and it has a certain palliative effect. This study aims to investigate the acute and late side effects of a three-dimentional printing non co-planar template (3D–PNCT) for computed tomography (CT)-guided radioactive 125I seed (RIS) implantation in recurrent cancer of the head and neck. Between January 2016 and December 2016, forty-two patients with local recurrent malignant tumors of the head and neck received 3D–PNCT-assisted RIS implantation. The prescribed dose was 110–160 Gy. Preoperative planning design, production of individual guide plates, RIS implantation, postoperative dose evaluation, and follow-up were completed for all patients. Side effects in the skin, mucous membranes, blood and spinal cord were evaluated. All patients underwent surgery successfully. Duration of follow-up was 4–14 (median, of 8.5) months. The activity of a single RIS was 0.34–0.7 (median, 0.6) mCi. The number of RIS was 10–126 (median, 34). The number of implantation needles was 4–31 (median, 11). The mean D2cc (dose to the most exposed 2-cc volume) and D0.1cc (dose to the most exposed 0.1-cc volume) of the skin were 24.9 (7.1–85.5) and 47.5 (9.4–167.2), respectively, whereas those of the spinal cord were 8.4 (4.5–33.3) and 14.2 (13.6–63.0), mucosa were 35.1 (4.2–82.8) and 87.0 (6.6–214.1), parotid glands were 16.2 (12.8–19.7) and 29.8 (26.1–33.4) and those of the trachea were 17.9 (2.5–45.9) and 32.7 (3.9–83.9), respectively. No case had an acute reaction of grade ≥ 3. Three cases had a grade-1 skin reaction. Blood toxicity did not occur, nor spinal-cord injury. Xerostomia was not aggravated than that of before brachytherapy. One case had a grade-3 nerve response. 3D–PNCT-assisted RIS implantation can provide good accuracy for positioning. For local recurrent malignant tumor of head and neck, there were no obvious adverse reactions.