Overview

The tonsils, a subsite of the oropharynx, are the most common site for oropharyngeal cancer. The prevalence of tonsil cancer has been rising in the last few years. Common symptoms of tonsil cancer include an asymptomatic mass, ear pain, difficulty swallowing, and throat pain. Tonsil cancer is the most prevalent histological manifestation of squamous cell carcinoma.¹ However, heavy alcohol consumption and tobacco use may potentially increase the risk of tonsil cancer, and the condition is frequently associated with human papillomavirus (HPV) infection. Radiation therapy, chemotherapy, and surgery are included in the therapies for tonsil cancer.²

Diagnosis of tonsil cancer

Diagnosis begins with a biopsy confirming signs of tonsil cancer.² Then the imaging tests are ordered to make pictures of the body. They may help the healthcare team better understand the size of cancer. Imaging tests also can look for signs that cancer may have spread beyond the tonsils or if the cancer spreads to other areas of the body.

Imaging tests used for diagnosis of tonsil cancer include

• Computerised tomography, also called CT
• Magnetic resonance imaging, also called MRI
• Positron emission tomography, also called PET³

Computerised tomography (CT) scan

A computerised tomography (CT) scan is a procedure that obtains detailed images of the inside of the body using x-rays and a computing device. It captures images from different points of view. These views are combined by a computer to create a three-dimensional (3D) image.⁴ CT scans are used by healthcare professionals when the objects cannot be viewed through the standard X-rays.²

Preparation for CT scan

For the majority of scans, contrast medium is given to enhance the visibility of body tissues during the scan either by injection or orally.⁴ For CT scan, intravenous lines will place and contrast medium or dye injections into the vein. If healthcare professionals want to detect if tonsil cancer metastasis to intestines gives contrast medium orally to highlight the intestines.²

CT scan helps healthcare professionals to diagnose tonsil cancer because it improves visibility of tissues and also determines if the cancer spreads to other organs or blood vessels. During urination, IV contrast agents typically leave the body in 24 hours.²

Application in tonsil cancer

• To diagnose tonsil cancer
• To determine the size of tonsil cancer
• To help work out where the cancer is, how close it is to nearby organs like lymph nodes, or if it has metastasised to other organs
• To check how well treatment is working
• As part of the follow-up after treatment⁴

Advantages of CT scan

• The scan is quick, it takes fewer than 10 or 15 minutes. After that, you can return to your normal activity
• CT scans have good visualisation for body structures that cannot be seen with X-rays. Each organ's details are displayed on a CT scan for a more accurate and clear image² 

Limitations of CT scan

• For people who have an allergic reaction to the contrast agent (dye), this reaction can be serious or can be a minor reaction
• A small amount of ionising radiation will be used in CT scans to capture images, which may cause a slight increase in the risk of developing cancer^2,4

Magnetic resonance imaging (MRI) scan

The method of diagnosis known as magnetic resonance imaging (MRI) uses a magnetic field, radio waves, and a computer to produce detailed images of organs, soft tissues, bone, and almost every other internal body structure. MR technology enables a doctor to assess various body tissue types and differentiate between healthy and diseased tissue.⁵ MRI stands for magnetic resonance imaging. They take between 15 and 90 minutes for scans.⁴

Preparation for MRI scan

First any metal containing objects should be removed before the examination because metal and electrical objects can interfere with the MRI machine's magnetic field, cause burns, or turn into dangerous projectiles. They are not permitted in the examination room. Your healthcare professional must be aware of any metal-containing items or medical devices that are implanted in your body prior to your MRI scan.

Then, diagnosing tonsil cancer may require the use of a contrast medium with an MRI to improve the visibility of the tumour. Gadolinium is used as a contrast agent, which enhances the quality of the image by changing the magnetic characteristics of nearby water molecules. To administer, a contrast medium doctor needs to insert an IV line in vein to inject it.²

Application in tonsil cancer

• MRI is used to detect tonsil cancer
• Determine the size of the tonsil tumour
• Determine the stage of tonsil cancer and whether it has spread
• To determine the effectiveness of treatment⁴

Differences between MRI and CT

In the MRI magnets, radio waves and computers are used to obtain the images for the tumour or other parts of the body. While X-rays and computers are used in CT scans,

Healthcare professionals frequently prefer MRI scans over CT scans when examining the soft tissues or non-bony areas of the body. Because they don’t employ the harmful ionising radiation of X-rays when using MRI are also safer.²

MRI is more effective than CT at showing the extent to which the tumour has penetrated internal tissues. Showing whether or not the tissue left over after therapy is cancerous can be one of its most helpful applications.⁴

Advantages of MRI scan

• In MRI, X-rays and other radiation are not used, for this reason it is the best choice when a patient will need periodic imaging for treatment, diagnosis, and monitoring²
• MRI scan is superior to other scans when healthcare professionals need to examine soft tissues inside the body⁴

Limitations of MRI scan

• It takes a long time, approximately between 15 and 90 minutes⁴ 
• MRI scanning is more expensive than CT scanning or X-ray imaging
• Some people are not able to have an MRI. Devices like pacemakers and insulin pumps may malfunction or be displaced by the MRI's magnetic field² 

Positron emission tomography (PET) scan

PET scan is one form of nuclear medicine imaging that uses a tiny and safe dose of radioactive material known as radiotracers, used to identify regions of the body where cells are more active than usual. This radiotracers is administered through the IV route.^2,4

PET scan has a role in cancer diagnosis. It also has an important function in finding out whether and where cancer has spread (metastasis).⁴

PET scan images can detect cellular changes in organs and tissues earlier than CT and MRI scans because they focus on biological processes within your body. This gives them the potential to find disease in its earliest stage.²

Can PET scans be Combined with other scans?

To obtain more details and high-quality images, PET scans can be combined with CT scans. These are called PET-CT scans. Generally, when PET-CT scans are used to diagnose cancer, the results are more accurate than PET or CT scans alone.⁴

Recently, new technology has been used in some hospitals, which combines PET and MRI scans to obtain extremely high contrast images. PET-MRI scan is used by providers for diagnosing and monitoring head and neck cancer of which tonsil cancer is a type of them.²

Application in tonsil cancer 

• PET scan is used to detect whether tonsil cancer has spread to the lymph nodes⁴
• Detects metastasis (if the cancer has spread in other parts of the body)
• To check the effectiveness of treatment
• Determine the recurrence of the cancer after treatment²

Advantages of PET scan

• PET scan has an important role to find out metastasis
• Have a potential role to detect cancer and other diseases in its earliest stage²

Limitations of PET scan

• PET scan required radioactive tracer to perform, and some people have allergies to it^2,4
• Diabetic patients may not absorb the sugar, which is found in radiotracer, which can affect scan results²

Comparison Table: CT, MRI, and PET Scans for Tonsil Cancer

Summary

The role of imaging techniques in tonsil cancer is to diagnose, manage, and monitor. These imaging techniques include CT, MRI, and PET, each of which has its own strengths and limitations. The selection of the appropriate imaging techniques depends on many factors, including patient condition, the purpose of examination, and resource availability.

A multidisciplinary approach ensures optimal use of these technologies, enabling accurate diagnosis, effective treatment planning, and improved patient outcomes.