When you or someone you love is diagnosed with cancer, one of the first questions is: “How far has it spread?” It’s a natural and necessary concern because the answer will shape every treatment decision that follows.

That’s where PET-CT comes in. This advanced nuclear medicine scan offers some of the most accurate staging and monitoring available in cancer care today. It doesn’t just show what the cancer looks like; it shows how active it is.

While PET-CT can be helpful in a wide range of cancers, it’s particularly effective in certain types. In these cases, it can mean the difference between catching the spread early or missing it, and between tailoring treatment precisely or relying on less specific approaches.

Let’s explore the cancer types where PET-CT has the biggest impact, and why it’s become such a powerful part of care.

How PET-CT works: a quick refresher

PET-CT stands for Positron Emission Tomography – Computed Tomography. It combines two types of scans in a single session:

• CT provides a detailed map of the body’s structure, showing the size, shape and location of organs and any visible tumours.
• PET reveals metabolic activity, or how cells are behaving. Cancer cells often use more energy than normal ones, and a small, safe amount of radioactive glucose helps highlight those hotspots.

This combination gives doctors a more complete picture, especially in cancers that are harder to assess using structure alone.

Where PET-CT matters most

Lymphoma

• Why PET-CT is used: It’s incredibly sensitive in detecting lymphoma activity, even in lymph nodes that appear normal on CT or MRI.
• How it helps: It improves staging, identifies spread to distant nodes or organs, and is key in monitoring treatment. If a tumour stops lighting up mid-treatment, that’s a strong sign it’s responding.
• In practice: Doctors often do a PET-CT at staging and again after a few cycles of chemotherapy to decide if treatment should continue, change or stop early.

Lung cancer

• Why PET-CT is used: CT scans can show a tumour in the lung, but they can’t always tell if the lymph nodes are involved. PET-CT can.
• How it helps: It avoids unnecessary surgery in patients whose cancer has already spread, and helps identify those who could benefit most from curative treatment.
• In practice: A scan may reveal that a small tumour is part of a more advanced stage, completely changing the course of treatment.

Breast cancer

• Why PET-CT is used: It detects spread to bones, liver, or lungs, places where breast cancer can hide even when other scans look normal.
• How it helps: It guides oncologists in choosing the right systemic therapy and helps monitor whether treatment is having an effect.
• In practice: For patients with metastatic breast cancer, it offers insight into whether lesions are active or healing, allowing more targeted, ongoing care.

Colorectal cancer

• Why PET-CT is used: It can detect tiny areas of recurrence that might not show up on other scans.
• How it helps: It helps determine whether surgery is possible or if a patient needs chemotherapy first.
• In practice: PET-CT scans are often used post-surgery to remove a tumour if blood markers start rising, or if recurrence is suspected but not visible on standard imaging.

Melanoma

• Why PET-CT is used: It highlights active metastases that aren’t visible on traditional imaging.
• How it helps: It helps oncologists choose between surgery, immunotherapy, or targeted treatment, and it ensures that treatment is focused where it’s needed most.
• In practice: It can reveal hidden spread to lymph nodes or organs even after a skin lesion has been removed.

Cervical and gynaecological cancers

• Why PET-CT is used: Cervical and gynaecological cancers often spread to pelvic lymph nodes or nearby organs in ways that are difficult to see clearly on standard imaging.
• How it helps: It supports accurate staging, which is essential in deciding whether to proceed with surgery, chemotherapy or radiation.
• In practice: In cervical cancer specifically, PET-CT can guide radiation therapy to target affected nodes more precisely.

Prostate cancer

• Why PET-CT is used: This type of scan, particularly with a specialised tracer called PSMA (Prostate-Specific Membrane Antigen), offers far greater sensitivity than traditional imaging in detecting prostate cancer spread.
• How it helps: It’s especially useful when PSA (Prostate-Specific Antigen, a protein produced by the prostate gland) levels rise after treatment. Conventional scans don’t show where the cancer might be, but PET-CT can detect small, otherwise hidden areas of recurrence or spread, allowing doctors to plan targeted treatments.
• In practice: Doctors use it to determine whether salvage therapy, radiation, or hormone therapy is appropriate, and to avoid unnecessary treatment when no active cancer is found.

Head and neck cancers

• Why PET-CT is used: It picks up activity in deep lymph nodes and tissues that are difficult to assess physically.
• How it helps: It supports surgical planning, determines if cancer has spread beyond the primary site, and helps track recovery.
• In practice: It can also help assess treatment response, since scarring after radiation can make other scans difficult to interpret.

Why accuracy matters

In cancer care, precision isn't just helpful, it's lifesaving. When doctors know exactly what’s happening inside the body, they can:

• Avoid unnecessary or ineffective treatments
• Focus therapy where it matters most
• Change course quickly if treatment isn’t working
• Reduce exposure to harmful side effects
• Improve long-term outcomes

PET-CT plays a powerful role in making that kind of precision possible.

A clearer path forward with Life Healthcare

At Life Healthcare, we are committed to bringing the most advanced medical imaging to South African patients. Our PET-CT facilities are designed with care, accuracy, and patient comfort in mind, and our nuclear medicine specialists work closely with your oncology team to ensure the right decisions are made at the right time.

Whether you’re just beginning your cancer journey or further along in treatment, know that tools like PET-CT are here to guide the way, one clearer scan at a time.

To learn more or access helpful patient resources, visit our Health Library or speak to your Life Healthcare team.