Radiotherapy: Future of Cancer Treatment

Abstract

There are more than 200 different kinds of cancer. Cancerous tumours can infiltrate surrounding tissues and spread to other parts of the body, resulting in the formation of new tumours (a process called metastasis). Anything that causes an abnormal development of a normal bodily cell has the potential to produce cancer. Cell abnormalities can be caused by a variety of factors such as chemical or toxic compound exposures, ionizing radiation, pathogens and genetics. Chemotherapy, hormone therapy, immunotherapy, precision medicine, or personalized medicine, stem cell transplant, surgery, targeted therapies and radiotherapy are many of the treatments used. Radiation therapy's main objective is to deprive cancer cells of their ability to multiply (cell division). In recognition of a century of progress since Marie Curie earned her second Nobel Prize for radium research, the United Kingdom has declared 2011 as the Year of Radiation Therapy. Continuing advancements in radiation therapy techniques and research in understanding the biology of cancer cell responses to radiation have aimed to improve cancer patient survival and decrease treatment side effects during the last 100 years. The applications of radiation treatment are addressed in this review.

Introduction

Cancer is defined as the uncontrollable development of abnormal cells in any part of the body. There are more than 200 different kinds of cancer. Cancer can be caused by anything that causes a normal body cell to grow abnormally; basic categories of cancer-related or causative factors include chemical or toxic substance exposures, ionizing radiation, certain infections, and human genetics (: Charles Patrick Davis, 2021).

Cancer may begin nearly anywhere in the billions of cells that make up the human body. Human cells normally expand and multiply (via a process known as cell division) to create new cells as needed by the body. Cells die as they get old or injured, and new cells replace them.

This ordered process can sometimes break down, resulting in aberrant or damaged cells growing and multiplying when they shouldn't. Tumors, which are masses of tissue, can arise from these cells. Tumors may be malignant or benign ("What is cancer?," 2021).

Cancerous tumours can infiltrate surrounding tissues and spread to other parts of the body, resulting in the formation of new tumours (a process called metastasis). Malignant tumours are another name for cancerous tumours. Many malignancies, including leukemias, produce solid tumours, while cancers of the blood do not.

Benign tumours do not infiltrate or spread into surrounding tissues. Benign tumours seldom reappear after being excised, but malignant ones do. However, benign tumours can grow to be extremely big. Some, such as benign brain tumours, can produce significant symptoms or even be fatal ("What is cancer?," 2021).

Anything that causes an abnormal development of a normal bodily cell has the potential to produce cancer. Cell abnormalities can be caused by a variety of factors, some of which have been related to the development of cancer. Some cancers have no known origins, while others have environmental or lifestyle triggers or may develop from many causes. Some people's genetic composition may have an impact on their development. Many people get cancer as a result of a combination of these causes. Although determining the beginning event(s) that cause cancer to grow in a given individual is frequently difficult or impossible, research has supplied doctors with a number of plausible reasons that, alone or in combination with other causes, can cause cancer to develop.

·         Chemical or toxic compound exposures: Benzene, asbestos, nickel, cadmium, vinyl chloride, benzidine, N-nitrosamines, tobacco or cigarette smoke (contains at least 66 recognised probable carcinogenic chemicals and toxins), asbestos, and aflatoxin are some of the chemicals and toxins found in tobacco or cigarette smoke.

·         Ionizing radiation: Radiation from alpha, beta, gamma, and X-ray-emitting sources, uranium, radon, ultraviolet rays from sunshine, and radiation from alpha, beta, gamma, and X-ray-emitting sources.

·         Pathogens: HPV, EBV, or Epstein-Barr virus, hepatitis B and C, Kaposi's sarcoma-associated herpes virus (KSHV), Merkel cell polyomavirus, Schistosoma spp., and Helicobacter pylori are among the microorganisms being investigated as potential agents.

·         Genetics:  A number of specific cancers have been linked to human genes and are as follows: breast, ovarian, colorectal, prostate, skin, and melanoma.

(: Charles Patrick Davis, 2021)

Types of cancer treatments:

Because each cancer kind necessitates a different treatment plan, an accurate cancer diagnosis is critical for suitable and effective therapy. Radiotherapy, chemotherapy, and/or surgery are commonly used in the treatment of cancer. The first step in therapy is to figure out what you want to get out of it. The primary objective is to either cure cancer or significantly extend life. A significant objective is to improve the patient's quality of life. Support for the patient's physical, psychological, and spiritual well-being, as well as palliative care in the last stages of cancer, can help achieve this.

Breast cancer, cervical cancer, oral cancer, and colorectal cancer, for example, all have excellent cure rates when identified early and treated according to best standards.

Even when malignant cells are present in other parts of the body, several cancer forms, such as testicular seminoma and other types of leukaemia and lymphoma in children, have excellent cure rates if adequate therapy is offered ("Cancer," 2021).

·         Chemotherapy 

·         Hormone therapy

·         Immunotherapy

·         Precision medicine, or personalized medicine

·         Stem cell transplant

·         Surgery 

·         Targeted therapies

Chemotherapy 

Chemotherapy, which employs medicines to destroy fast-growing cancer cells, is one of the most frequent treatment choices for many cancer types.

Chemotherapy has a number of purposes: it can be used to cure cancer, prevent it from returning, stop it from spreading, and/or slow its progression. It may also help alleviate pain and other cancer-related symptoms by shrinking big tumours.

Chemotherapy is a cancer treatment that can be used alone or in conjunction with other treatments. Chemotherapy is frequently used with other cancer therapies ("Cancer treatments," 2021).

Hormone therapy

Hormone treatment is used to treat malignancies that develop by secreting hormones, such as prostate and breast cancer. Hormone therapy is a cancer treatment that slows or prevents the development of cancers that grow by secreting hormones. Hormone therapy is also known as hormone treatment, endocrine therapy, or hormonal therapy ("Hormone Therapy to Treat Cancer," 2015).

Immunotherapy

Cancer immunotherapy is an attempt to use the immune system's incredible capability and selectivity to treat cancer. Despite the fact that cancer cells are less immunogenic than infections, the immune system is capable of detecting and destroying them. Tumors, on the other hand, usually obstruct the formation and function of immune responses. As a result, the goal for immunotherapy is to create methods that effectively and safely enhance antitumor responses using advancements in cellular and molecular immunology (Blattman & Greenberg, 2004).

Precision medicine, or personalised medicine

Precision medicine, often known as precision oncology, is a personalised approach to cancer treatment. It utilises genetic testing to evaluate your genes or the behaviour of cancer cells to develop tailored medicines and cures. Every tumour contains a unique collection of mutations and proteins. Your physicians can use precision medicine to evaluate these trends and create a treatment plan based on them.

Targeted treatments are the medicines and therapies that fall within the precision medicine umbrella. These medicines "target" cancer cells' particular proteins or mutations and prevent them from growing ("Cancer treatments," 2021).

Stem cell transplant

Stem cell transplants are treatments that replace blood-forming stem cells in patients whose stem cells have been damaged by high-dose chemotherapy or radiation therapy used to treat certain malignancies.

In most cases, stem cell transplants do not immediately combat cancer. Rather, they assist you in regaining your capacity to create stem cells after being exposed to extremely high doses of radiation, chemotherapy, or both.

The stem cell transplant, on the other hand, may operate directly against cancer in multiple myeloma and some forms of leukaemia ("Stem Cell Transplants in Cancer Treatment," 2015) .

Surgery

Surgery aids in the treatment of cancer by physically removing it from the body. To access the malignancy, certain forms of surgery require cutting into your body. Your surgery may be open (with a bigger incision) or minimally invasive (with a smaller incision) depending on the location of the tumour and other variables (with tiny incisions). Other surgical procedures use a different approach, such as cryosurgery, which uses freezing temperatures to kill cancer cells.

The objective of surgery in cancer treatment varies from total to partial tumour removal. Surgery is performed exclusively on malignancies that are situated in a specific region, as opposed to systemic therapies like chemotherapy, which treat cancer across the body ("Cancer treatments," 2021).

Targeted therapies

New cancer targeted treatments based on therapeutic antibodies or small molecules have improved tumour specificity and reduced toxicity. Despite this, numerous obstacles to cancer therapy persist, including drug resistance, cancer stem cells, and high tumour interstitial fluid pressure. Increased interstitial fluid pressure, for example, reduces the efficiency of therapeutic drug absorption in many solid tumours. One of the most promising approaches to overcoming these obstacles is ligand-targeted treatment, which may be used to improve targeting and deliver larger doses of anti-cancer drugs to tumour tissue (Wu et al., 2006).

Palliative care

Palliative care is a type of treatment that aims to alleviate rather than cure cancer-related symptoms and enhance the quality of life for patients and their families. Palliative care can make people's lives easier. It is especially important in areas where a significant number of patients are in late stages of cancer with little hope of recovery.

Palliative care can provide relief from physical, psychological, and spiritual issues for more than 90% of cancer patients in advanced stages.

Pain management and palliative care for patients and their families require effective public health initiatives that include community and home-based care ("Cancer," 2021).

Radiation therapy

To kill cancer cells, radiation treatment uses high-dose energy beams. Radiation therapy is a cancer treatment that can be used alone or in combination with other treatments. It may also aid in tumour shrinkage and the alleviation of symptoms associated with advanced malignancies.

External beam radiation, internal radiation, and systemic radiation are the three primary types of radiation treatment.

External beam radiation uses a machine to provide radiation to the tumour.

Internal radiation refers to the placement of a radiation source inside your body, either inside or near the tumour.

Orally or with an injection, systemic radiation treatment distributes radioactive medicines ("Cancer treatments," 2021).

Types of radiation therapy

a)      External beam radiation

The most frequent kind of cancer radiation treatment is external beam radiation. The energy beams are external, meaning they emanate from a machine outside of the body. The beams, which penetrate the body to reach the cancer spot, are carefully aimed by a healthcare practitioner.

Teletherapy is another term for external beam radiotherapy.

It employs a gadget that sends high-energy rays into the tumour from outside the body. It's done at a hospital or treatment facility during outpatient visits. It's generally administered over a period of weeks, and it's occasionally given twice a day for a period of time. External radiation does not make a person radioactive, therefore they do not need to take particular measures at home ("How Radiation Therapy Is Used to Treat Cancer," 2019).

b)     Internal radiation therapy

Internal radiation therapy, commonly known as brachytherapy, is the second most common kind of radiation treatment. A doctor puts a radiation-containing implant in or near the cancer location during this therapy.

The implants are available in a variety of forms, including tube, wire, capsule, seeds, and pellets.

A radioactive source is inserted into or near the tumour inside the body. Radiation may be implanted and left in the body to function in some kinds of brachytherapy. It is sometimes implanted in the body for a short length of time before being removed. This is determined by the cancer kind. For a period of time, special safety precautions are required for this sort of radiation ("How Radiation Therapy Is Used to Treat Cancer," 2019).

c)      Systemic radiation therapy

Another type of internal radiation therapy is systemic radiation therapy.

It entails swallowing a radioactive material that goes throughout the body in search of and kills malignant cells.

Certain kinds of cancer are treated using radioactive medicines that are taken orally or injected into a vein. After then, the medicines move throughout the body. Following the administration of these medications, it might require to take extra measures at home for a length of time ("How Radiation Therapy Is Used to Treat Cancer," 2019).

Significance Of Radiotherapy for Cancer Treatment

Radiation treatment is responsible for 40% of all cancer cures worldwide and improves the quality of life for many more. Despite this significant advantage, the Commonwealth government's overall cost of radiation therapy is less than 9 cents for every dollar spent on cancer diagnosis and treatment. In Australia, each year of life saved by radiation therapy is less expensive than one saved through alternative cancer therapies. Radiation therapy, in other terms, is a very cost-effective cancer treatment ("What is Radiation Oncology?," 2020).

For many common malignancies, such as breast cancer, bowel cancer, uterine cancer, skin cancers, and prostate cancer, radiation treatment administered before or after surgery is very successful in lowering the chance of cancer recurrence. Radiation therapy, with or without medication therapy, can be used as the major curative treatment in various malignancies (for example, prostate, head and neck, bladder, lung, cervix, and skin cancers), avoiding the dangers of surgery and organ removal ("What is Radiation Oncology?," 2020).

Radiation therapy is highly helpful for pain and other issues caused by cancer, such as bleeding from the lungs or bladder, in some tumours that are too advanced to be treated. For example, in around 75% of patients, discomfort in the bones caused by cancer spread can be greatly reduced or entirely eliminated ("What is Radiation Oncology?," 2020).

This treatment can be used alone or in conjunction with other therapies like as surgery or chemotherapy. This treatment makes use of sophisticated technology to deliver high doses of radiation to cancer cells. Radiation treatment is used to treat cancer in only the portion of the body that is afflicted. As a result, radiation therapy is often regarded as the most effective treatment for cancer in its early stages. Radiation treatment is divided into two types: IMRT (intensity-modulated radiation therapy) and Image-guided radiation therapy (IGRT) ("Significance Of Radiation Therapy,").

Conclusion

With continuous attempts to create novel radiation treatment modes and procedures that continue to enhance the survival and quality of life of cancer patients, radiation remains an essential modality for cancer treatment. Radiation therapy-related toxicities have become a concern as clinical results of cancer treatment have improved. Through dose fractionation and conformal radiation methods, the sparing of normal cells/tissues has increased thanks to the advent of mechanistic biology research and advancements in radiation technology. Radiation is also being used in conjunction with molecular targeted therapy in order to improve the radiation treatment's therapeutic ratio.

By: Areesha Ameem 

 

References

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