Malignant tumors have become a major cause of health threat in China, and the situation of “difficult to diagnose and difficult to treat” in the process of diagnosis and treatment is inevitable, which brings unprecedented challenges to oncologists. On January 6, the first “Long March Difficult Tumor Forum and Master Forum on New Clinical Advances in Tumor” was held. The executive chairman of the conference, Professor Zang Yuan-sheng, director of the Department of Oncology of Changzheng Hospital of Second Military Medical University, was interviewed by Medical World before the conference and shared his wonderful views on the hot and difficult issues related to the diagnosis and treatment of refractory tumors, as well as special cases worth seeing, which should not be missed! How to determine the progression of tumor disease and how to “remove the fake and keep the real”? In the process of disease development, tumor patients may have complex clinical manifestations due to tumor infiltration, compression and metastasis involving various systems and organs; in the process of disease diagnosis and treatment, various complications and adverse drug reactions may occur due to various invasive diagnosis and treatment methods and the use of chemotherapy drugs. Therefore, whether certain sudden changes in a patient’s condition are disease progression or complications need to be carefully identified by clinicians to avoid misjudging the condition. Professor Zang pointed out that the first symptom to pay attention to is infection, because patients with advanced tumors have low immunity and poor nutritional status, and often have infections, including respiratory tract infection, urinary tract infection and gastrointestinal tract infection. When encountering such tumor patients in clinical practice, we should not assume that the disease is progressing when we see that the patient’s condition has taken a sharp turn, but should analyze carefully and formulate the most suitable treatment plan, if it is an infection, giving anti-infection treatment can achieve better results. Heart failure is also very common in clinical practice, because chemotherapy for tumor patients requires a large amount of infusion, and excessive infusion can easily lead to cardiac insufficiency, and some patients can show shortness of breath. If we misjudge the condition at this time and try to give more infusion to correct the disease progress, it may aggravate the heart failure and even endanger the life. If the patient’s shortness of breath can be relieved in the sitting position, simple diuretic therapy and vasodilator therapy can be used to relieve the patient’s symptoms. There are also drug allergies, nutritional disorders in patients with gastrointestinal tumors and other conditions that can easily cause misjudgment by clinicians, which we will sort out in this meeting, share the experience of excellent cases, and review them in the light of the latest research progress, hoping to enhance the exchange of experience with our colleagues and bring better survival and prognosis for patients. II. Crizotinib for lung cancer saves patients with malignant fibrous histiocytoma! In recent years, some clinical trials of “allogeneic treatment” have been conducted in Europe and the United States, and they have been named as “basket trials”, but they have become a popular theory in the field of difficult-to-treat tumors. The concept is to ignore the anatomy of the tumor. The concept is to try the same treatment regimen on patients with similar intrinsic characteristics (mainly the same driver mutation) regardless of the anatomical location of the tumor and see how it works. With regard to the “basket theory”, foreign countries have published relatively heavyweight research results, and some preliminary explorations have been made in China since 2015. The Department of Oncology of Long March Hospital has carried out relevant research, and Prof. Zang introduced us the three key questions of the research: 1) Are there any other tumor treatment targets in the current tumor? 2. If the same target as other tumors is found, is the targeted drug equally effective for the current tumor? 3. If the target drug is effective, what is its mechanism of action and how efficient is it? In early 2016, Prof. Zang saw a young patient with an atypical malignant fibrous histiocytoma. The situation at that time had no chance of surgery, and there was massive infiltration in the 4th cervical vertebra-7th cervical vertebra, and the patient’s life was in danger, but there was no treatment plan to learn from. But Professor Zang wanted to find a solution that might work, even if there was only a glimmer of hope. “We tried the basket theory, trying to find targets for targeted drugs in the patient’s tumor where other tumors already had efficacy.” ”At first, we administered chemotherapy according to the standard and recommended treatment for soft tissue tumors, but the chemotherapy was very ineffective, and the patient’s condition continued to deteriorate, with him lying in bed immobile and at risk of breaking his cervical spine at any time. Fortunately, we did second-generation gene sequencing for the patient and found that he had a very rare, but potentially effective fusion mutation – a novel fusion of the ALK and CARS genes.” However, this fusion has been rarely reported domestically abroad, and there is a lack of relevant treatment experience. Based on data on the use of ALK inhibitors in lung cancer treatment and after searching for relevant information from multiple sources, Prof. Zang’s treatment team thought the patient might benefit from an ALK inhibitor, and after fully informing the patient and including him in the study, the patient was given crizotinib, an inhibitor against the ALK target. After treatment with crizotinib, the patient’s lesions rapidly regressed and his condition showed miraculous improvement.