27 Malignant Neoplasms (Cancer) – Diagnostic Tests

Recommended Screening and Diagnostic Tests

Screening for cancer can begin even before the presence of cancer is observed and this is because cancer can often become quite widespread and less treatable before observable signs and symptoms are noticed.  Treating cancer as early as possible leads to better outcomes in terms of survival rates as well as in reducing short- and long-term illnesses, impairments, or disabilities.

Recommended Screening involves regular screening, and there are several routine screening tests available in Canada.  Please note that guidelines change in response to ongoing research and available of new technology.  Check your current local guidelines.  To give you a rough idea in the meantime, in February 2024 they were:

1. Mammograms (x-rays) for Breast and Mammary Tissue Cancer: often recommended annually after the age of 40, to individuals that have higher risk factors which include female biological sex, first-degree relatives with breast cancer due to genetic risk factors (i.e. inheritance of BRCA1, BRCA2, TP53, or PALB2 gene variants). Recommended every 2yrs for people age 50-74 with average risk factors (no personal history, female biological sex, and if transfeminine, have used feminizing hormones for at least 5yrs).
2. Pap Tests for Cervical Cancer: often recommended every 2-3 years for those with high risk factors (all people with cervix, 21+ years of age, sexually active).
3. Fecal Immunochemical Test (FIT): for Colorectal Cancer: recommended for everyone every 2 years between 50-74 years of age.
4. Prostate Cancer Screening:  Prostate-Specific Antigen (PSA) serum marker test and digital rectal exam (DRE).  Typically, PSA tests are performed only if a person has a high risk of prostate cancer, as PSA can also be high for BPH (Benign Prostate Hypertrophy). High risk factors for Prostate Cancer include age (over 50yrs, family history, and genetics, African or Caribbean ancestry).  DRE is used to detect present of hard nodules indicative of Prostate Cancer.
5. Lung Cancer Screening:  Low-Dose Computed Tomography (LDCT) annually between 55-74yrs of age for smokers who currently smoke or quit fewer than 15 years ago.
6. Liver Cancer:  ultrasound screening and liver function tests are recommended every 6-12 months for those at risk.  Risk factors include: chronic HBV (Hepatitis B virus) infection or chronic HCV (Hepatitis C Virus) infection and cirrhosis (liver is very damaged, scarred and not functioning well),
7. Self-Examinations: recommended monthly palpations for lumps for:  breast and mammary tissue cancer and testicular cancer.
8. Skin Self-Examination: recommended monthly examining of moles and warts for changes in colour, size, and/or border shape.

Diagnostic Tests and Procedures

There are many different procedures, lab tests, and assessments that can be done to both diagnose and monitor the treatment of cancer.  This section will discuss the more common types of tests and procedures performed.

1. 1. Imaging: using

• 1. • • X-rays = creates 2D image of radio-dense tissue (e.g., bone)
       • Computed Tomography, CT scans = creates 3D x-ray image
       • Magnetic Resonance Imaging, MRI = creates 3D image of soft tissue
       • Endoscopy = Video camera on flexible tube, can be used for taking biopsies
       • Positron Emission Tomography PET scan = uses radioisotope-tagged glucose to monitor activity levels of tissues.  Cancerous cells are hypermetabolic and will accumulated tagged glucose).
  2. Blood Tests: types include
     1. Tumor Markers: are elevated levels of proteins – being produced by the cancer (usually fetal in nature – as cells have regressed).  For example:
        • CEA (carcino-embryonic antigen):  can indicate colon cancer
        • PSA (prostate specific antigen) test: high PSA can indicate prostate cancer or benign prostatic hypertrophy (BPH)
        • hCG (human chorionic gonadotropin) test:  can indicate testicular cancer
        • CA125: can indicate ovarian cancer
        • AFP (alpha-fetoprotein): can indicate hepatocellular cancer
     2. Complete Blood Counts
        • Hemoglobin & all blood cell levels – high/low levels may occur with cancer
          (also tested during chemotherapy treatment; e.g. leukemia)
        • Blood Chemistry Tests:  can measure blood components to assess function of different organs (e.g. electrolyte panel, liver enzyme function test, kidney function = BUN and creatinine test, and blood glucose)
  3. Urinalysis:
     • Urine tests can be used to check for cancerous proteins shed from kidney or bladder cancers (and check for other types of urinary system diseases)
  4. Genetic Testing:
     • Genetic Testing: Blood or Saliva; indicates risk for developing cancer (not certainty).  Genetic tests may be performed if there is a family history of an inherited type of cancer. Inherited cancers are rare, making up 5-10% of all cases.
       • Family Cancer Syndromes – such as:
         1. Hereditary Breast and Ovarian Cancer (HBOC) is more likely if there is a family history of BRCA1 and BRCA2 gene mutations
         2. Hereditary Retinoblastoma
  5. Cytological tests: require biopsy or cell sample
     • Cell Collection: cells or tissue are gathered using swabs, or needles (e.g., lumbar puncture or bone marrow aspiration), or surgical incisions, for example:
       • Breast biopsy – guided by ultrasound, using wide bore needle.
     • Grading:  Histological and cytological examinations using a microscope to determine degree of differentiation and tumor type (e.g., Pap test of cervical cells). Cells are graded (0-IV) with IV being least differentiated and most anaplastic.
     • Hormone Receptor Status Test:  Cells may be tested for hormone promoter sensitivities, (e.g., estrogen-dependent tumors) for example:
       • Positive Receptor Test Result: indicates that there are hormone receptors in the breast cancer cells indicates cancerous cells have receptors for estrogen (ER), progesterone (PR), or both, which means the cancer’s growth is stimulated by those hormones.  ~2/3 of breast cancers are ER and PR positive.
         • ER/PR Positive cancers will be treated with hormone therapy to block those receptors (e.g., hormone receptor blockers)
         • Surgery or radiation may be done to remove hormone producing glands (e.g., removal of ovaries = oophorectomy).
       • Negative Receptor Test Result: indicates that the cancerous cells do no have ER or PR and are therefore not dependent on estrogen or progesterone hormones for growth.
     • Cytology results of biopsied cells are the most dependable confirmation of malignancy

Grading and Staging Cancer:

Grading:

• Requires a biopsy of cells that are being assessed for signs of cancer.
• The cells are graded based on how different they look from normal differentiated cells (grade 1-4)
• Grade 1 = well differentiated, cells look close to normal, slow growing
• Grade 2 = moderately differentiated
• Grade 3 = poorly differentiated
• Grade 4= undifferentiated, cells look the most abnormal, more likely to be growing and spreading quickly

Staging: is a measurement of how far the tumor has spread through the body and can indicate the best treatment strategies as well as determine the prognosis.  Cancer is staged using the TMN system: Tumor size, Metastasis extent, and number of Lymph Nodes involved,

• T = Primary Tumor Size:  staged from 1-4, with stage 4 being the largest
• M= distant Metastasis = staged from 0-1,
  • with stage 0 = in situ, not spread, and 1 = cancer has spread
• N = Lymph Node Involvement:  staged from 0-3,
  • with stage 0 = no cancer in nearby lymph nodes; 3 = more lymph nodes contain cancer and some lymph nodes may be distant

Altogether the stages indicate whether the cancer is:

• Carcinoma in situ = abnormal cells are present, but no spread has occurred to nearby tissue
• Localized = cancer is limited to primary site and immediate vicinity with no sign of spread elsewhere
• Regional = cancerous cells have spread to nearby lymph nodes, tissues or organs
• Distant = cancerous cells have spread to distant parts of the body