Cancer metastasis: Welcome back to “The Science Of Health”, ABP Live’s weekly health column. Last week, we discussed how the brain stores memories, and the significance of a memory’s location in the brain in determining how useful it will be for future situations. This week, we discuss the instances in which head and neck cancers metastasise, or spread to other locations in the body and cause tumours to grow there.
Head and neck cancers, which can occur in the squamous cells lining the mucosal surfaces of the head and neck, that include the oral cavity, throat, and voice box, and also in the mucosal surfaces of the paranasal sinuses and salivary glands, and nerves in the head and neck, may metastasise to different locations. These include lymph nodes in the neck. However, squamous cell carcinoma may sometimes develop in the lymph nodes of the upper neck even when there is no head and neck cancer elsewhere. This could be because the original primary tumour is too small. The cancer that develops in the lymph nodes in such a case is known as metastatic squamous cell carcinoma with occult primary, according to the US National Institutes of Health (NIH).
ABP Live spoke to Dr Vikas Talreja, Medical Oncologist, Regency Hospital, Kanpur, and Dr Kanury V S Rao, Co-Founder and Chief Scientific Officer, PredOmix, a Gurugram-based health-tech company, and asked them about the instances in which head and neck cancers may metastasise.
The experts explained that regional lymph nodes, distant lymph nodes, lungs, liver, and bones are the most common sites of metastasis.
“Metastasis to regional lymph nodes is a concerning pattern, as it signifies the spread of cancer beyond its primary site. Lymph nodes act as filters, and cancer cells can get trapped and grow there. From the lymph nodes, cancer can further spread to distant organs, especially the lungs and liver, through the lymphatic system or bloodstream,” Dr Talreja explained.
He said that proximity of the affected structures to the primary cancer site, and the extensive network of lymphatic and blood vessels in the head and neck region are some potential factors responsible for the spread of head and neck cancers. “The invasive nature of some head and neck cancers contributes to their ability to infiltrate nearby tissues and spread.”
Dr Rao explained that metastasis occurs when cancer cells break away from the primary tumour in the affected area and travel to other parts of the body through the bloodstream or lymphatic system, and may happen at various stages of the disease.
Since regional lymph nodes are located in close proximity to the primary tumour, head and neck cancers may travel through the lymphatic system and manifest themselves in the nodes.
When head and neck cancers enter the bloodstream and spread to distant organs and tissues in the body, the occurrence is known as distant metastasis. “Common sites of distant metastasis include the lungs, liver, bones, and brain,” Dr Rao said.
When head and neck cancers are at an advanced stage, the tumours can grow extensively and invade nearby structures, such as the throat, jaw, sinuses, or base of the skull. This is called local invasion.
“Delayed diagnosis and neglected treatment can allow cancer cells to grow and metastasise to other regions before medical intervention occurs,” Dr Rao said.
The type and stage of head and neck cancers may determine their potential to spread. Dr Rao explained that some types of head and neck cancers are more aggressive and prone to metastasis than others. “Advanced stages of cancer are more likely to have already spread to other regions compared to early-stage tumours.”
Smoking, alcohol consumption, and human papillomavirus (HPV) infection are unhealthy lifestyle practices that can increase the likelihood of cancer spreading, Dr Rao said. “Unhealthy lifestyle factors can impact the aggressiveness of the tumour and its ability to metastasise.”
In order to prevent metastasis, or to manage the spread of tumours, patients should adopt certain practices. These include early detection and appropriate treatment, regular screening, prompt management of primary tumours, and targeted therapies, Dr Talreja said. Such measures can help improve outcomes and reduce the risk of metastasis. It is also important to closely monitor regional lymph nodes to detect early signs of metastasis, and to allow for timely intervention.
Dr Talreja suggested that people must adopt a healthy lifestyle, avoid tobacco and excessive alcohol consumption, and practise safe sexual behaviours to reduce the risk of head and neck cancers. “Regular check-ups and screenings can help detect cancer at an early stage when treatment is more effective.”
According to Dr Rao, not all head and neck cancers will spread to other regions, and the likelihood of metastasis varies from person to person. Therefore, regular follow-up care is important to manage head and neck cancers, and reduce the risk of their spread.
According to the NIH, there is an increased risk of a second primary cancer developing in people who have been treated for head and neck cancers. The second primary cancer usually occurs in the head, neck, oesophagus or lungs, and its risk of developing depends on the site of the original cancer. However, people who consume tobacco and alcohol are at a greater risk of developing a second primary cancer, compared to others.
Therefore, people must quit tobacco in order to reduce the risk of developing head and neck cancers. Also, patients who have had head and neck cancers in the past must refrain from consuming tobacco to reduce the risk of developing a second primary tumour.
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