Diagnostic Tests and Imaging Studies in Cancer

The diagnosis of cancer usually requires a combination of different tests. These may be used to confirm the presence of a tumour, determine its type, assess its extent (staging), identify molecular biomarkers and plan the most appropriate treatment. Modern precision oncology combines clinical findings, imaging studies, pathological assessment and, increasingly, genetic and molecular testing.

Biopsy

A biopsy is the most important test for confirming most cancers. It involves obtaining a sample of tissue or cells for laboratory analysis by a pathologist.

There are several types of biopsy:

  • Needle biopsy.
  • Endoscopic biopsy.
  • Surgical biopsy.
  • Ultrasound-, CT- or MRI-guided biopsy.
  • Liquid biopsy (in selected tumours and clinical situations).

In addition to confirming the diagnosis, a biopsy can determine the tumour subtype and provide tissue for molecular studies that help guide personalised treatment.

Blood Tests

Blood tests form part of the initial assessment for many patients with suspected or confirmed cancer. They can help evaluate:

  • General health status.
  • Liver and kidney function.
  • Blood cell counts.
  • Metabolic or inflammatory abnormalities.

In some cases, specific tumour markers may also be measured to support diagnosis, assess response to treatment or detect recurrence. However, tumour markers are generally not sufficient on their own to diagnose cancer.

Bone Marrow Aspiration and Biopsy

Bone marrow is the tissue inside bones where blood cells are produced.

Obtaining a bone marrow sample, usually from the pelvis, may be necessary to diagnose or monitor:

  • Leukaemias.
  • Lymphomas.
  • Multiple myeloma.
  • Other haematological disorders.

The sample is analysed using microscopic, immunological and molecular techniques.

Bone Scan

A bone scan is a nuclear medicine imaging test used to identify abnormalities in bone metabolism.

Following the intravenous administration of a very small dose of a radioactive tracer, images are obtained that may show:

  • Bone metastases.
  • Fractures.
  • Infections.
  • Other bone disorders.

For some specific cancers, bone scans may now be complemented or replaced by PET-CT scanning according to current clinical recommendations.

Colonoscopy

A colonoscopy allows direct examination of the rectum and colon using a flexible tube equipped with a high-resolution camera.

During the procedure, the specialist can:

  • Detect polyps.
  • Obtain biopsies.
  • Remove precancerous lesions.

Colonoscopy is used both to investigate digestive symptoms and to confirm findings identified through colorectal cancer screening programmes.

Colposcopy

Colposcopy is a detailed examination of the cervix performed using a specialised optical instrument called a colposcope.

It is mainly recommended when:

  • Cervical cytology (smear test) is abnormal.
  • An HPV test is positive.
  • Suspicious clinical findings are present.

It allows abnormal areas to be identified and targeted biopsies to be taken.

Computed Tomography (CT Scan)

Computed tomography (CT) uses X-rays and computer processing to generate detailed images of the inside of the body.

It may be performed with intravenous or oral contrast to improve visualisation of organs and tissues.

CT is one of the most frequently used investigations for:

  • Diagnosis.
  • Cancer staging.
  • Assessing response to treatment.
  • Follow-up after treatment.

Cystoscopy

Cystoscopy allows examination of the inside of the bladder and urethra using a flexible or rigid cystoscope.

Depending on the procedure, it may be performed using local anaesthesia or sedation.

It is commonly used to:

  • Investigate blood in the urine.
  • Diagnose bladder tumours.
  • Obtain biopsies.
  • Perform certain endoscopic treatments.

Upper Gastrointestinal Endoscopy (Gastroscopy)

Gastroscopy allows visualisation of the oesophagus, stomach and duodenum using a flexible endoscope equipped with a camera.

During the procedure, the specialist may:

  • Take biopsies.
  • Remove certain lesions.
  • Carry out specific endoscopic treatments.

The procedure is usually performed under sedation to improve patient comfort.

Lumbar Puncture

A lumbar puncture involves obtaining a sample of cerebrospinal fluid using a needle inserted between the lumbar vertebrae.

It may be used to:

  • Diagnose certain lymphomas and leukaemias.
  • Detect involvement of the central nervous system.
  • Administer intrathecal treatments.
  • Measure cerebrospinal fluid pressure.

Mammography

Mammography is an imaging test that uses low-dose X-rays to examine breast tissue.

It is currently the main screening test used in population-based breast cancer screening programmes in Spain and many other countries.

Mammography can detect breast cancers at an early stage, often before symptoms develop. In some cases, it may be supplemented with breast ultrasound or breast MRI.

Magnetic Resonance Imaging (MRI)

Magnetic resonance imaging (MRI) uses magnetic fields and radio waves to produce detailed images without the use of ionising radiation.

It is particularly useful for examining:

  • The brain.
  • The spinal cord.
  • The breast.
  • The prostate.
  • The liver.
  • Soft tissues and the musculoskeletal system.

In many cases, intravenous contrast is administered to improve diagnostic accuracy.

Positron Emission Tomography (PET)

PET is a nuclear medicine imaging technique that evaluates the metabolic activity of tissues.

After administration of a radioactive tracer, areas with increased cellular activity can be identified on the images.

PET is used to:

  • Stage certain cancers.
  • Detect metastases.
  • Evaluate treatment response.
  • Identify cancer recurrence.

PET-CT

PET-CT combines in a single examination:

  • The anatomical information provided by CT imaging.
  • The functional and metabolic information provided by PET imaging.

This combination offers greater diagnostic accuracy and is widely used for staging and follow-up in many types of cancer.

PSA (Prostate-Specific Antigen)

PSA is a protein produced by the prostate gland that can be measured through a blood test.

An elevated PSA level may be associated with:

  • Benign prostatic enlargement (benign prostatic hyperplasia).
  • Inflammation or infection of the prostate.
  • Prostate cancer.

Current international guidelines recommend that PSA testing should be based on an informed and individualised decision after considering its potential benefits and risks, as it may lead to overdiagnosis and overtreatment. It is not recommended as a universal screening test for all men.

Ultrasound

Ultrasound uses high-frequency sound waves to produce real-time images of internal organs and tissues.

It is a:

  • Non-invasive test.
  • Painless procedure.
  • Radiation-free imaging technique.

Ultrasound is used to examine many areas of the body and to guide biopsies and other diagnostic procedures.

X-rays

X-rays use ionising radiation to create images of structures inside the body.

Although they have partly been replaced by more advanced imaging techniques in oncology, they remain useful for:

  • Assessing the lungs and chest.
  • Examining bones.
  • Detecting certain abnormalities or complications.

Some X-ray examinations may require the use of contrast agents to improve visualisation of anatomical structures.