Dr Khrutsozo Kikhi
Nasopharynx is a space located just behind and in continuation with the nasal cavity. This space is in close relation with bones, nerves, blood vessels, muscles, and the brain and is often involved by the tumor. Nasopharyngeal cancer is uncommon cancer in most parts of the world. The incidence rate per 100,000 people per year ranges from 0.6 in the United States and Japan to 17.8 and 26.9 in Hong Kong and Southern China respectively. As per the national cancer registry program 2020, the incidence of nasopharyngeal carcinoma in Nagaland is the highest in the country with an incidence of 14.4 /100,000 for men and 6.5 /100,000 for women.
This cancer mainly has a bimodal age distribution i.e. from 15 – 25 years and 2nd peak at 50 – 59 years. In high–riskpopulations, the peak incidence occurs in the fourth and fifth decades. The male-to-female ratio is 2:1 to 3:1.
The cause of this cancer is mainly due to three factors:
1) Genetic factors: The high incidence of Nasopharyngeal Carcinoma among Southern Chinese populations and its descendent suggests a component of genetic susceptibility. The HLA loci and its haplotypes A2, B46, and b17 are associated with an increased risk of Nasopharyngeal Carcinoma. However, studies are limited with respect to genetic factors worldwide and thus far we have no evidence in our Naga population.
2) Environmental factors: Consumption of salted fish and meat, exposure to dust, fumes, formaldehyde, smoking, and alcohol are implicated. This is due to the presence of di-methyl-nitrosamine, a carcinogen in salted food that has been found to induce cancer. This could be one of the main risk factors in our population
3) Epstein-Barr Virus (EBV): The level of EBV DNA in tumors has been associated with Nasopharyngeal Carcinoma. A baseline level of EBV is recorded before treatment starts as the levels of EBV DNA can be used to assess disease response during treatment and can also be used as a marker for detecting disease recurrence after treatment completion. There is a type called non-keratinizing undifferentiated nasopharyngeal carcinoma which has been found to be associated with EBV infection. This is the cancer type that is most prevalent in our state and it could possibly be due to EBV infection.
Watch out for signs:
1) Painless swelling of the neck
2) Nasal block, frequent nose bleeding, nasal discharge
3) Decrease hearing
4) Persistent headaches are usually one-sided but can be both-sided also
5) Decrease vision, double vision
6) Slurring of speech
7) Facial numbness
8) Sore throat
9) Occasionally difficulty in swallowing, weight loss
How does it spread?
It spread via 2 routes i.e. the lymphatic system and the blood. The higher the stage, the more the chance of the disease spreading to other parts. The most common site for spread is the bone followed by the lungs and the liver. In rare cases, it can spread to the brain and the skin also. In 3% to 6%, patients present with the spread of the disease when present in the hospital, and 18% to 50% spread occurs during the course of the disease.
How to diagnose?
Upon suspicion, an endoscope is inserted via the nasal cavity and a biopsy is taken for confirmation and also to know the type of tumor. MRI of the neck is the scan of choice for staging cancer. A CT scan of the chest and abdomen is also done to know if there is a spread of the tumor to other parts of the body. Another type of scan is a PET CT scan, which scans the whole body in one go and it has been found to be more sensitive in detecting the spread of cancer. Blood tests are done before starting the treatment, especially with chemotherapy. After the investigations are done, the disease is staged from stage I to stage IV based on the American Joint Committee on Cancer (AJCC)
How to Treat?
Treatment usually consists of chemotherapy and radiation and sometimes, though very rare, surgery if there is disease recurrence. The sequence of treatment with chemotherapy and radiation therapy is based on the stage of the disease. One of the most effective treatments is combining both chemotherapy and radiation therapy which has been shown to improve the survival of patients significantly in multiple studies. The advantage of this treatment is because of the fact that this cancer is highly sensitive to both chemotherapy and radiation therapy. The treatment with radiation therapy has advanced so much when compared with treatment 20 years ago. This is due to the fact that the treatment of the cancer is highly precise and accurate with Intensity Modulated Radiation Therapy (IMRT) which treats cancer with the required dose and decreases the radiation dose to nearby organs thereby reducing the side effects to a large extent.
The outcome of the treatment is dependent on the stage of the disease at presentation and also the tolerability of treatment. The higher the stage, the lower the 5-year survival and also the higher chance of spreading the tumor to other parts of the body. For stage I, II, III, and IV the chance to survive is approximately 90 – 95%, 80%, 60% - 70%, and 40% - 50% respectively. Due to a lack of awareness and ignorance, about 90% to 95% of the patient in our state present with locally advanced disease i.e. in stage III and stage IV. This could be the reason why the survival of the patients is much lesser. Apart from chemotherapy and radiation therapy, the family’s support in terms of emotional, mental, and spiritual plays a major role in the treatment outcomes of the patient. The World Health Organization also emphasizes the need for wholesome treatment of the person and not just the physical aspect alone. Early detection and taking preventive measures will result in bringing about a good outcome and also reduce the burden of this cancer in our state to a large extent.
The writer is Consultant Radiation Oncologist, Department of Radiation Oncology, CIHSR Chümoukedima