NEOPLASIA Part 12: Lab diagnosis of cancer

Summary

This tutorial from 'Pathology Made Simple' explores the laboratory diagnosis of cancer, covering general considerations, specific methods like cytopathological and histopathological examinations, and advanced techniques such as immunohistochemistry, flow cytometry, molecular diagnostics, imaging, liquid biopsies, and tumor markers. The video offers a concise overview of how these techniques contribute to cancer diagnosis, management, and treatment response evaluation.

Takeaways

• 🔬 Cytopathological examination is a crucial method for diagnosing cancer, involving exfoliative cytology, such as Pap smears, and interventional cytology, like fine needle aspiration cytology.
• 🔍 Histo病理ological examination allows for accurate cancer diagnosis based on microscopic features of the neoplasm, using various tissue sampling methods including needle biopsy, endoscopic biopsy, incision biopsy, and excision biopsy.
• 🚀 Immunohistochemistry is a special technique to detect specific proteins in tissue sections using antibodies, aiding in determining factors like estrogen receptor status in breast cancer, which is important for predicting response to hormone therapy.
• 🌟 Applications of immunohistochemistry include differentiating tumor types, assessing tumor aggressiveness, and categorizing undifferentiated cancers based on antigen-antibody reactions.
• 🚰 Flow cytometry is a technique that analyzes individual cell properties as they pass through a nozzle in a fluid stream, useful for identifying and characterizing specific types of cancers, such as leukemia.
• 🧬 Molecular techniques in cancer diagnosis include Polymerase Chain Reaction (PCR) for amplifying specific DNA sequences, Fluorescence In Situ Hybridization (FISH) for detecting genetic changes, Gene sequencing for identifying mutations, and Next Generation Sequencing (NGS) for rapid genetic analysis.
• 📈 Imaging techniques like X-rays, ultrasound, CT scans, MRI, and PET scans are used in conjunction with other methods for diagnosing cancers, providing detailed images of tumors and lesions.
• 🩸 Liquid biopsy is an emerging technique using blood to detect the genetic makeup of cancers, offering real-time snapshots of a patient's cancer and the ability to detect cancer before symptoms manifest.
• 📊 Tumor markers are substances produced by tumors that can be detected in the body and are used to monitor disease progression or treatment effectiveness, but they lack sensitivity and specificity and should be used in conjunction with other diagnostic methods.
• 📚 The video provides a comprehensive overview of various diagnostic methods for cancer, emphasizing the importance of combining different techniques for accurate diagnosis and treatment management.

Q & A

What are the initial steps taken when a patient presents with vague symptoms suggestive of cancer?

The initial steps include a thorough physical examination to find clues for cancer diagnosis, followed by routine blood investigations to check for conditions like anemia or polycythemia, which might indicate an underlying malignancy.

What is exfoliative cytology and how is it used in cancer diagnosis?

Exfoliative cytology involves studying cells that are spontaneously shed from the lining of an organ. Examples include Pap smears for cervical lesions and examination of cells in body fluids like ascitic fluid or pleural fluid.

What is interventional cytology and how does it differ from exfoliative cytology?

Interventional cytology involves obtaining cells through active intervention, such as fine needle aspiration cytology (FNAC). In FNAC, material is aspirated from a lesion (e.g., a breast lump) using a fine needle and studied on a glass slide.

What are the methods used to obtain tissue for histopathological examination?

Methods include needle biopsy (core needle biopsy), endoscopic biopsy, incisional biopsy, and excisional biopsy. These techniques involve taking tissue samples from the lesion for microscopic examination to make an accurate diagnosis.

How does immunohistochemistry (IHC) help in cancer diagnosis?

IHC detects specific proteins in tissue sections using antibodies that bind to those proteins. It helps in determining the type and aggressiveness of the tumor, differentiating between different tumor types, and categorizing undifferentiated cancers.

What is flow cytometry and how is it used in cancer diagnosis?

Flow cytometry analyzes the properties of individual cells in a fluid stream as they pass through a small nozzle and scatter light. It helps in identifying and characterizing specific types of cancers, such as leukemia, by detecting specific cell surface markers.

What molecular techniques are used in cancer diagnosis and what do they detect?

Molecular techniques include Polymerase Chain Reaction (PCR), fluorescence in situ hybridization (FISH), gene sequencing, and Next Generation Sequencing (NGS). These techniques detect and analyze genetic changes, mutations, and chromosomal abnormalities in cancer cells.

What are the common imaging techniques used in cancer diagnosis?

Common imaging techniques include X-rays, ultrasound examination, computed tomography (CT) scans, magnetic resonance imaging (MRI), and positron emission tomography (PET) scans. These techniques help visualize tumors and assess their extent.

What is liquid biopsy and how does it aid in cancer detection?

Liquid biopsy uses blood samples to detect genetic material shed by cancer cells. It provides real-time information about a patient's cancer, such as circulating tumor DNA (ctDNA) tests that can detect cancer before symptoms appear and monitor treatment response.

What are tumor markers and how are they used in cancer diagnosis?

Tumor markers are substances produced by tumors that can be detected in cells, blood, or body fluids. Examples include prostate-specific antigen (PSA), cancer antigen 125 (CA125), and alpha-fetoprotein (AFP). They help monitor disease progression and treatment effectiveness but lack sensitivity and specificity, so they are used in combination with other diagnostic methods.