Nasopharyngeal Carcinoma: Predilection Site, Common Symptoms and Treatments

Nasopharyngeal carcinoma (NPC) is a malignant tumor arising from the nasopharyngeal mucosa. Regions such as Guangdong in China are high-incidence areas, so NPC is also called "Guangdong cancer." NPC most commonly arises in the pharyngeal recess, a longitudinal deep fossa located behind the torus tubarius and between it and the posterior pharyngeal wall; statistics show that about 70-80% of NPCs originate here.

Why does NPC preferentially arise in the pharyngeal recess? Because this region is anatomically concealed and rich in mucosal folds, it is easily stimulated by external carcinogenic factors (such as Epstein-Barr virus and environmental toxins), and foreign matter often lingers here, leading to abnormal hyperplasia and carcinogenesis of mucosal epithelial cells. The pharyngeal recess is rich in lymphatic vessels, and the tumor easily metastasizes through lymphatic routes.

Common symptoms of NPC include nasal obstruction, blood in the nasal discharge or blood-streaked postnasal drip, and enlarged cervical lymph nodes. Some patients also have ear fullness, hearing loss, persistent headache and cranial-nerve involvement such as diplopia and facial numbness. Early symptoms of NPC are easily confused with the common cold and epistaxis and are often neglected by patients. Those with a family history of NPC should be alert to these symptoms and seek prompt examination; early detection improves the cure rate.

By the time most NPC patients are diagnosed, cervical lymph node metastasis has already occurred. The retropharyngeal lymph nodes and the jugulodigastric lymph nodes are most commonly involved. The typical lymphatic spread of NPC proceeds from the retropharyngeal nodes to the upper deep cervical nodes, then to the middle and lower cervical nodes, supraclavicular nodes, and on to contralateral or multiple systemic lymph nodes.

NPC can also metastasize hematogenously throughout the body. Distant metastases most often involve bone, lung and liver; some patients may develop brain metastases and adrenal metastases.

The tissues and organs around the pharyngeal recess are complex; nearby are the cranial and facial bones as well as brain tissue. Surgery in this area easily damages brain tissue, so radiotherapy is the treatment of choice for NPC. NPC is highly radiosensitive, and early patients can achieve a high cure rate with radiotherapy alone.

During radiotherapy, however, conformal radiotherapy should be chosen as far as possible to precisely locate the tumor and reduce damage to surrounding tissues. NPC is prone to radiation injury during treatment; after radiotherapy, patients may develop sequelae such as dry mouth and hearing loss, which affect their quality of life.

Some medical institutions are now using proton and heavy-ion beams to treat NPC. Compared with conventional radiotherapy, this approach can precisely locate the tumor and, through its unique Bragg-peak effect, release maximum energy at a specific depth, thereby reducing damage to surrounding healthy tissue and causing fewer side effects. However, whether its cure rate is superior to conventional radiotherapy remains unproven; the treatment is not widely available and is expensive, beyond the reach of average patients.

Chemotherapy is commonly used for locally advanced NPC, but it is generally combined with radiotherapy. Chemoradiotherapy reduces the risk of local recurrence of NPC by about 20-30%. However, many patients discontinue chemotherapy midway because they cannot tolerate its side effects.

Traditional Chinese medicine also has some efficacy in treating NPC, but it is not advisable to rely on TCM alone. Combining TCM with radiotherapy and chemotherapy can further improve the success rate of NPC treatment.