Nasopharyngeal cancer is one of the most common malignant tumors in China, and its treatment principle is mainly radiotherapy. Nasopharyngeal cancer can achieve better clinical efficacy after radiotherapy, which is the main treatment method for tumors, like surgery and chemotherapy. With the development of science and technology, radiotherapy technology has been continuously improved, from the previous body painting frame to two-dimensional conformal, and then to three-dimensional conformal, radiotherapy technology has made great progress; especially the intensity modulated radiotherapy and IGRT radiotherapy have been carried out, and the technology of radiotherapy has made a qualitative leap. Among them, intensity-modulated radiotherapy is recognized as the best method for radiotherapy of nasopharyngeal cancer.
As we all know, due to the special anatomical location of nasopharynx, nasopharyngeal cancer tumors are surrounded by brainstem, eye, parotid gland, jaw bone, temporomandibular joint and other dangerous organs. These organs are not immune to radiation, but the function of these organs will be affected if they receive higher radiation doses. Due to the technical limitations of conventional radiotherapy, the dose to these organs at risk is often the same as the dose to the tumor. As patients with nasopharyngeal carcinoma survive longer after treatment, various long-term complications of radiotherapy, including radiation osteonecrosis, cranial nerve damage, severe dry mouth, difficulty in opening the mouth, and hearing loss, may occur, resulting in poorer quality of patient survival. In addition, due to the need to protect important organs such as brainstem and optic nerve, certain parts of the tumor are often irradiated at low doses, resulting in uncontrolled tumor or recurrence. Therefore, there are often patients with nasopharyngeal cancer who have tumor recurrence after conventional radiotherapy, which brings pain to patients.
Intensity modulated radiotherapy is a new radiotherapy technology, which uses the function of CT simulation and 3D treatment planning system to establish a visual 3D image of the tumor tissue and surrounding endangered organs, so that the tumor area can be irradiated more accurately and the surrounding endangered organs can be better protected. The radiation is adjusted by special tools such as physical compensators, static or dynamic gratings, etc., so that the high-dose area is consistent with the tumor volume. Studies have shown that improving the accuracy of tumor irradiation, increasing the dose to the tumor, and shortening the duration of the treatment can improve the local control rate of nasopharyngeal cancer. Intensity-modulated radiation therapy not only allows the tumor to be located in the high-dose area, but also allows for a low dose to normal tissue. Through the intensity-modulated radiotherapy of more than 1,000 patients with nasopharyngeal carcinoma treated in our hospital, we found that not only the local recurrence rate of patients with intensity-modulated radiotherapy is lower than that of conventional radiotherapy, but also the toxic side effects such as dry mouth, difficulty in opening mouth and neck fibrosis are significantly lower than that of conventional radiotherapy.
Of course, there are also shortcomings such as longer waiting time, more expensive treatment cost, and difficulty in revising treatment plan. However, these shortcomings cannot stop the happiness brought by intensity-modulated radiotherapy to patients with nasopharyngeal cancer, and we believe that intensity-modulated radiotherapy will definitely make greater contribution to the majority of tumor patients!