Diagnosis

Diagnosis of melanoma is through histological examination.  What does this look like?

Often, melanoma starts as a irregular looking mole on the skin. That mole, with a little bit of surrounding ‘normal’ tissue is cut out (ie biopsy) by a health care professional.  This biopsy is taking  the entire mole including the epidermal and dermal layer of the skin. The biopsied mole is cut into very thin slices and mounted onto a glass slide and stained with H&E.  All of this work is performed by a medical laboratory technologist with a histology specialization.  After a preliminary glance of the stained slide of the biopsied mole, the technologist then sends the slide to a histopathologist for diagnosis, using some of the skills and terms Lyz had demonstrated in the previous chapter.

Treatment

Treatment of melanoma  – as well as most cancers – can be grouped as:

• Chemo- and radiotherapy:  both of these strategies aim to kill rapidly dividing cells whether by:

• • Chemotherapy uses chemicals which slow down or inhibit cell division. Usually, chemotherapy is absorbed in the entire body – so cell division in normal healthy cells will also be affected.
  • Radiotherapy uses radiation to kill rapidly growing tumour cells.  Usually, radiotherapy is localized to the site of the cancerous growth.  However, some normal tissue – especially skin – will be affected by radiation  if it happens to be in the path of the radiation beam.  An important issue for radiotherapy is that certain organs have different ‘tolerance’ for radiation exposure.

• Surgical excision:  remove the cancerous tissue and some surrounding tissue.
  • Requires biopsy of surrounding structures and lymph nodes to assess for possibility of nearby metastases as a hint to possible further spread.
  • Surgical excision of metastases will not cure the cancer – but it can relieve signs & symptoms caused by the metastasis.

Medical Laboratory Sciences (Anatomic Pathology) in surgical treatment of cancer

Listen to Marion Regan, a medical laboratory technologist, speak about how technologists are giving instantaneous histological specimens to surgeons while the surgeon is excising cancerous tissues.

^{Histological Preparation of Biopsy Tissue During Surgery by Marion Regan & Jennifer Kong, licensed under CC BY NC}

• Immunotherapy:  allow the body’s immune system to recognize abnormal cancer cells and remove them.
  • This is in the early stages of implementation.
• Targeted therapy:  inhibit the genes (or their protein products) which were damaged – thus stopping the uncontrollable cell division.
  • This is in the early stages of research and implementation.

^{Treatment of Melanoma by Lyz Boyd, licensed under CC BY NC}

Prevention

What’s unique about melanoma – compared to many cancers – is that one can lower one’s risk by by limiting exposure of the skin & eyes to the sun.  Continuous monitoring of the skin – especially moles – may allow for early detection and, hence, early treatment.  Patient survival rates increase when cancers are detected early.

^{Prevention of Melanoma by Lyz Boyd, licensed under – CC BY NC}

Section Review

• Whether it is a biopsy of a suspicious mole or surgical excision of a tumour, a medical laboratory technologist will histologically prepare and stain the tissue, allowing for visual examination of key features of cancerous changes and whether the basement membrane is intact.
• Depending on the level of invasion of spread, melanoma can be treated by surgical excision of the tumour, localized treatment with radiotherapy, or systemic treatment with chemo- or immunotherapy.
• Prevention measures of modifiable risk factors (e.g.  limiting sun damage to skin)  can reduce the risk of developing melanoma.  However non-modifiable risk factors (e.g. age, genetics, skin tone) can not be changed; thus, there is always a risk.

Review Questions