Nasopharyngeal cancer -- most common cancer in Asia

By Tan Eng Huat

This interactive health column is jointly run by The Jakarta Post and Singapore-based Parkway Group Healthcare. The column covers various medical topics and appears twice a month. Readers are encouraged to ask questions through the Post's at features@thejakartapost.com.

SINGAPORE (JP): Nasopharyngeal cancer (NPC) or "nose cancer" is a well-recognized disease largely seen in this part of the world. It is the commonest head and neck cancer in countries such as Singapore and Hong Kong in contrast to the West. Hence, many studies were conducted in these countries with the aim of improving the treatment outcome of this cancer. These studies have contributed significantly to a better understanding of this disease.

The cause of NPC is still essentially unknown. There is no association with the use of tobacco or alcohol abuse. However, there may be possible links with a particular virus called the Epstein-Barr virus (EBV), and the consumption of preserved food such as salted fish during the weaning period.

The nasopharynx is a small area at the back of the nasal passage. Due to its rich blood and lymphatic supply, cancer arising in the nasopharynx tends to spread early to the lymph nodes in the neck resulting in neck lumps that tend to be painless, and has a greater tendency to spread to other organs compared to other head and neck cancers. Spread of the cancer via the bloodstream can occur in up to 30-50 percent of the patients within the first two to five years from diagnosis. The commonest site of spread is the bone. Other organs that can be affected include the liver and lungs. It is not uncommon to involve all three sites.

Do I have NPC?

Early symptoms of NPC include bleeding from the nose, blockage of the nose or ears, and a ringing sound in the ears. As the nasopharynx is close to the base of the brain where nerves pass through to control eye movement, voice and swallowing, NPC, if not detected early, can affect these nerves resulting in headache, double vision, difficulty in swallowing or change in the quality of the voice. Diagnosis is made from biopsy of the nasopharynx or fine needle biopsy of the neck nodes.

What is the stage?

After the diagnosis of NPC is made, it is important to perform further tests to determine if the cancer is confined to the nasopharynx or has spread elsewhere. This process is called staging. Computer scans of the nasopharynx, chest and liver, and bone scans are helpful for this purpose. On knowing the stage, treatment will be tailored accordingly.

What is the treatment?

Unlike other kinds of head and neck cancer, surgery is not recommended for patients with NPC. NPC is extremely responsive to radiotherapy and chemotherapy, more so than other head and neck cancers. Hence both these types of treatment form very important treatment methods.

Early stage NPC (stage 1 and 2) is best treated with radiotherapy alone. This can result in a cure in a large proportion of such patients. However, those with more advanced stages (stage 3 and 4) will require combined treatment with chemotherapy and radiotherapy. If patients with stage 3 or 4 NPC are treated with radiotherapy alone, they stand a higher risk of relapse in the nose, neck or other distant organs within two to five years of treatment.

A major study done in the United States has shown that the addition of chemotherapy to radiotherapy resulted in a higher cure rate for patients with more advanced NPC. In this study, patients with stage 3 or 4 disease were randomized to either radiotherapy alone or a combination of six courses of chemotherapy with radiotherapy. Randomization is a scientific process of allocating treatment with removal of any bias towards either treatment methods. At the third year of follow-up, 76 percent of the patients who received both chemotherapy and radiotherapy were still alive compared with only 46 percent of those who received radiotherapy alone.

However, the use of both methods of treatment simultaneously will result in higher risk of serious side effects that can sometimes be fatal. This can be prevented if only patients who are sufficiently fit are selected for such a treatment approach.

It is also very important for the oncologists to be familiar with the potential side effects of combined treatment and how to manage such side effects before embarking on such an approach in their patients. Our study conducted in 1995 in Singapore has shown that combining chemotherapy with radiotherapy similar to that used in the United States can be done safely in Asian patients if adequate precautions are taken.

What about patients with widespread disease?

Patients whose disease has spread to other organs have incurable disease. However, that does not mean that nothing can be done for them. Our recent study of more than 200 patients with distant organ spread has shown that chemotherapy resulted in prolongation of survival. Due to the high responsiveness of NPC to chemotherapy, patients often experienced significant relief of their symptoms and improvement of their quality of life with treatment.

New chemotherapeutic drugs

A regimen used since the late 1970's comprising cisplatin and S-fluorouracil is still commonly used. This regimen is effective in up to 70 percent of the patients. In 1994, our study has shown that a new drug called paclitaxel is also effective in NPC. This was followed by another study done in 1996 where a combination of paclitaxel and carboplatin was shown to be highly effective. This new regimen is well tolerated and more convenient to administer than the older regimen. A recent study just completed has also resulted in an another new effective drug called gemcitabine. Gemcitabine was also found to be effective in those who had failed other chemotherapeutic drugs.

A significant number of patients with widespread disease are frail due to the ravages of the cancer on the body. These new agents with new treatment schedules are well tolerated even by these patients. With good response to treatment, the cancer cells in the body can be reduced significantly and their frailty can even reverse resulting in improved level of fitness. Hence, there is now greater enthusiasm to treat even these patients.

Conclusions

Treatment for NPC has improved over the past decade. The concept of combining chemotherapy and radiation with stage 3 and 4 disease is gaining wide acceptance and is likely to contribute to improving the cure rates for this group of patients.

New drugs and schedules of treatment have also spelt hope for those with incurable disease with better chances of surviving beyond two years even with widespread disease. Studies must continue if we want to improve the results of treatment further. Further studies looking at other, newer agents and new treatment schedules are in the planning stage now.

Dr. Tan Eng Huat is a consultant medical oncologist at Gleneagles Medical Center in Singapore.