Radiotherapy is the main treatment for nasopharyngeal carcinoma, but current clinical studies have concluded that chemotherapy is also an important tool in the treatment of nasopharyngeal carcinoma. For patients with intermediate to advanced nasopharyngeal carcinoma without distant metastases, chemotherapy is mainly used in combination with radiotherapy to improve the cure rate of the tumor; for patients with clinical and subclinical distant metastases, as well as patients with locally advanced cancer that cannot be cured by radiotherapy, chemotherapy is often the only effective treatment option available.
The combination of cisplatin-based chemotherapy and radiotherapy for locally advanced nasopharyngeal carcinoma has been reported to be effective in improving the survival rate of these patients. However, the choice of chemotherapy regimen and the way to combine chemotherapy with radiotherapy have been controversial. In the treatment of nasopharyngeal carcinoma, the possible chemotherapies used depending on the purpose of treatment are induction chemotherapy, concurrent radiotherapy, adjuvant chemotherapy, and palliative chemotherapy. In a Meta-analysis of eight randomized controlled trials of 1753 patients with locally advanced nasopharyngeal carcinoma, chemotherapy reduced the risk ratio of tumor failure or death by 24%, increased the 5-year survival benefit by 6%, and increased the 5-year tumor-related event-free survival benefit by 10%, with the greatest benefit in the concurrent radiotherapy modality, as well as improved local control and distant metastasis control rates. Concurrent radiotherapy ± induction or adjuvant chemotherapy has now become the standard treatment modality for locally advanced nasopharyngeal carcinoma.
Induction chemotherapy Induction chemotherapy refers to chemotherapy used before radiation therapy. The advantages of induction chemotherapy are that it may kill the hidden subclinical metastases; after induction chemotherapy, it can make the primary tumor shrink effectively, which is helpful to reduce the tumor load and relieve the clinical symptoms, reduce the lack of oxygen cells in the tumor center, enhance the radiosensitivity of the tumor and improve the local control rate; the nutritional status of patients before radiotherapy is generally better, and they tolerate chemotherapy better and have better compliance; in addition, the local blood supply to the tumor is good before radiotherapy. In addition, the local blood supply to the tumor is good before radiotherapy, and chemotherapeutic drugs are easier to reach the tumor interior and exert anti-tumor effects. Therefore, induction chemotherapy is still widely used in patients with localized mid- to late-stage nasopharyngeal carcinoma. However, the shortcomings of induction chemotherapy include delayed radiotherapy, decreased nutritional status, partially reduced tolerance of radiotherapy, aggravated side effects of radiotherapy, and increased treatment cost, etc. 2. Concurrent chemoradiotherapy Concurrent chemoradiotherapy is given at the same time of radiotherapy to synchronize the tumor cell cycle and increase the sensitivity of radiotherapy. The direct tumor-killing effect of chemotherapeutic drugs. Previously, a large number of studies have proved that cisplatin has its unique sensitizing effect of radiotherapy, and the toxic side effects of conventional dose are low, and its toxicity is not superimposed on the toxicity of radiotherapy, so cisplatin is considered to be one of the relatively good chemotherapeutic drugs for concurrent radiotherapy.
3.Adjuvant chemotherapy Adjuvant chemotherapy is the chemotherapy carried out after the end of radiotherapy for nasopharyngeal carcinoma. The purpose is to kill possible residual cancer cells in the local area after radiotherapy as well as systemic subclinical metastases, and may delay the occurrence of distant metastases. However, patients with nasopharyngeal cancer often have difficulty in tolerating adjuvant chemotherapy after radiotherapy because of unrecovered mucosal inflammation, poor nutritional status and low immune function. Several prospective clinical studies have also shown that adjuvant chemotherapy does not significantly improve the survival rate of nasopharyngeal carcinoma.
4.Palliative chemotherapy has always been considered incurable for distant metastatic nasopharyngeal cancer, and chemotherapy as a means of systemic treatment is of great significance for patients with distant metastasis; moreover, some patients with recurrence after radiotherapy have become important treatment means if the time between recurrence and the first course of radiotherapy is short or serious sequelae have been produced after radiotherapy. In recent years, there are many reports in the literature that a few patients with distant metastases have achieved long-term remission or survival through chemotherapy, suggesting that palliative chemotherapy has an important role in nasopharyngeal cancer.