Carcinomas And Cancer Risk

Introduction

Cancer is a devastating disease that unfortunately affects millions of people worldwide, with 1 in 2 people in the UK likely to develop cancer in their lifetime. Among the various types of cancers, carcinomas are the most common form and account for a significant proportion of cancer cases. Carcinomas are defined as cancers that begin in the skin or in tissues that line or cover internal organs.

Having a clear understanding of the link between carcinomas and cancer risk is essential for early detection, prevention, and effective treatment plans. This article will aim to explore the characteristics of carcinomas, identify the risk factors associated with their development, the various detection and treatment methods as well as emphasise the importance of proactive measures to mitigate and reduce cancer risk.

Types of carcinomas

Cancer is characterised by uncontrolled cell growth which can lead to tumours forming. Cancerous tumours can become malignant and invade surrounding tissues through metastasis - the breaking of cancer cells away from the original tumour and spreading to distant organs through the bloodstream and lymphatic system. Carcinomas are a type of cancer that originate within the epithelial cells. These cells line the internal and external surfaces of the body. Carcinomas can occur in organs such as the skin, lungs, breasts, prostate, and colon.¹ Carcinomas can spread to nearby tissues (invasisive) and to other parts of the body (metastatic).

Carcinomas can be categorised more broadly into types: 

• Squamous cell carcinoma (SCC) - Originates in the squamous cells that form on the outer layer of the skin and within the linings of holloworgans such as the lungs, throat, and cervix. Examples of squamous cell carcinomas include oesophageal squamous-cell carcinoma and squamous-cell carcinoma of the lung
• Adenocarcinomas - Found in the glandular tissues, which are responsible for the production and secretion of fluids such as mucus. Examples of adenocarcinomas include breast, kidney, lung, colon, and prostate cancers²
• Basal cell carcinoma (BCC) - Originates in the basal cell layer of epidermis (outer later of skin). This is the most common type of skin cancer
• Ductal carcinoma in situ (DCIS) - Originates in breast milk ducts. ‘In situ’ means it has not spread and is considered a non-invasive form of breast cancer and highly treatable
• Invasive (infiltrating) ductal carcinoma - Originates in breast milk ducts but spreads to nearby tissue and can spread to other parts of the body if not treated. It is the most common type of breast cancer

Carcinoma risk factors

Overview

There are a variety of risk factors that have been associated with increased risk of developing carcinomas.³ These range from various genetic factors such as genetic predisposition, environmental factors such as sun exposure and toxins, as well as lifestyle factors including tobacco and alcohol consumption.

Environmental, Genetic, and Lifestyle Factors

Lifestyle factors: 

• Age: Advancing age is a significant risk factor for the development of carcinomas. During the ageing process, increased exposure to certain environmental factors and cellular damage increases the likelihood of cancer development

• Tobacco and alcohol Use

The long-term effects of smoking tobacco and excessive alcohol consumption are major risk factors for various types of carcinomas, including lung, oral, oesophageal, and liver cancers This is due to these substances containing carcinogens that cause damage to DNA and disrupt normal cellular processes.

Environmental Factors:

• Ultraviolet (UV) radiation

Prolonged exposure to UV radiation from the sun or artificial sources, such as tanning beds, can increase the risk of developing skin carcinomas, particularly squamous cell carcinomas, aswell as melanomas

• Environmental factors

Exposure to certain environmental toxins, such as asbestos, benzene, and arsenic, is linked to an increased risk of developing specific types of carcinomas, these include bladder, liver and lung cancers.

• Hormonal factors

Hormonal imbalances or prolonged exposure to certain hormones can contribute to the development of carcinomas. Oestrogen exposure over a long period is associated with an increased risk of breast and endometrial cancers.

Genetic Factors:

• Genetic predisposition

Certain inherited genetic mutations have been shown to increase the risk of developing specific types of carcinomas. An example of these types of mutations includes the BRCA1 and BRCA2 genes. These have been shown to be associated with an increased risk of breast and ovarian cancersCarcinomas and cancer risk

There are links between some carcinomas leading to an increased risk of getting other cancers. Those with with skin cancers (basal cell carcinoma or squamous cell carcinoma) are more likely to later develop another form of cancer such as deadly skin cancer melanoma, lung, breast, colon and prostate cancers. This is likely due to mutations in proteins responsible for repairing DNA damage that leads to cancer.⁵ 

Prevention and early detection

Carcinomas can be a particularly aggressive type of cancer, especially if they metastasise. The ability to detect the presence of cancer as early as possible can allow for earlier intervention and hopefully prevent the cancer from spreading. Early detection methods include screening programs and genetic testing.6

Prevention

• Healthy Lifestyle - Adopting a healthy lifestyle can significantly reduce the risk of developing carcinomas. This includes maintaining a balanced diet rich in fruits, vegetables, and whole grains, engaging in regular physical activity, avoiding tobacco and excessive alcohol consumption, and managing stress effectively
• Sun Protection - UV damage has been  heavily linked to cancer.Practising adequate sun protection measures such as wearing sunscreen, protective clothing, and sunglasses, as well as limiting exposure to the sun during peak hours, can minimise the risk of skin carcinomas
• Regular Screening and Early Detection - Regular screening tests, such as mammograms, Pap smears, colonoscopies, and prostate-specific antigen (PSA) tests, can aid in the early detection of carcinomas. The UK has mass screening services for common cancers for specific risk factor groups, such as the cervical cancer screenings for people assigned female at birth (AFAB) over 25. Early diagnosis can often improve treatment outcomes and survival rates
• Genetic Counselling and Testing - If individuals are aware of a family history of certain carcinomas, they may benefit from genetic counselling and testing to identify potential inherited genetic mutations and make informed decisions about preventive measures. In the case of the BRCA1 and 2 genes, which have been directly linked to breast and ovarian cancers, those AFAB may chose  to have preventative surgery such as removal of breast tissue or a hysterectomy⁷

Treatment options

The treatment options for carcinomas depend on various factors such as the stage of cancer, location, and individual patient characteristics. Treatment options for carcinomas include:⁸

• Surgery - Often the primary treatment for carcinomas. It involves removing the cancerous tumour and nearby lymph nodes, if necessary. The extent of surgery depends on the size and location of the tumour. In some cases, minimally invasive techniques such as laparoscopic or robotic surgery may be used
• Radiation therapy - Uses high-energy X-rays or other types of radiation to kill cancer cells or shrink tumours. It can be used as the primary treatment for localized carcinomas or in combination with surgery or chemotherapy. External beam radiation therapy delivers radiation from outside the body, while brachytherapy involves placing radioactive sources near the tumour
• Chemotherapy - The most commonly used cancer therapy, involves using drugs to kill cancer cells. It is often used for carcinomas that have spread to other parts of the body (metastatic carcinoma) or as therapy after surgery to destroy any remaining cancer cells. Chemotherapy may be given orally or through intravenous infusion
• Targeted therapy- Works by targeting specific molecules or genetic mutations that are involved in the growth and progression of carcinomas. These drugs are designed to interfere with specific pathways in cancer cells, thereby inhibiting their growth. Targeted therapy can be used alone or in combination with other treatments
• Immunotherapy - Helps the immune system to recognise and attack cancer cells. It uses drugs that stimulate the immune system or block the proteins that prevent the immune system from attacking cancer cells. Immunotherapy has shown promising results in treating certain types of carcinomas, such as lung cancer and melanoma
• Hormone therapy - Can be used to treat certain types of carcinomas that are hormone-sensitive, such as breast and prostate cancer. It usually involves blocking or interfering with the production or action of hormones that promote the growth of cancer cells
• Palliative care - Focuses on relieving symptoms, managing pain, and improving the patient's quality of life

Summary

Carcinomas pose a significant threat to human health and require diligent efforts to understand and mitigate associated risks. By recogniSing the characteristics of carcinomas and identifying key risk factors, individuals can make informed choices about their lifestyle, undergo regular screenings, and adopt preventive measures. Proactive steps toward reducing cancer risk can lead to early detection, more effective treatments, and ultimately, improved outcomes for those affected by carcinomas.