Oncology Week 12: Tumors and Cell Division

Oncology Week 12

• Cancer: Altered cell growth and damaged DNA within cells. Normal cells have a purpose, tight adherence, orderly growth, and mitosis. Cancer cells lack a purpose, are harmful, metastasize, have looser adherence, and continuously divide, with larger nuclei compared to cytoplasm.

• Cell Division/Oncogenes: Oncogenes promote cell division. Cancer originates when an abnormal cell is transformed via genetic mutations. These cells then clone and proliferate, becoming invasive and gaining access to lymph and blood vessels.

• Benign Tumors: Growths that are usually harmless but may be problematic if located in a critical area, obstructing function. Benign tumors are well-differentiated (look like original tissue), encapsulated (contained), and do not spread. Slow growth and metastasis do not typically occur.

• Malignant Tumors: Always harmful and considered cancerous. They are undifferentiated (no resemblance to original tissue), not encapsulated, infiltrate tissues, have variable growth, metastasize, cause anemia, weight loss, and extensive tissue damage, and often lead to death.

• Hyperplasia: An increase in the number of cells, which can be normal or abnormal.

• Metaplasia: One cell type transforms into another, potentially affecting surrounding tissues.

• Cancer Spread: Cancer can spread through the lymphatic system and bloodstream. Lung cancer might spread to the bone, liver, and brain; colorectal cancer can spread to the liver; and prostate cancer can spread to the spine and lungs.

• Cancer Development: Cancer development involves changes (dysplasia) in normal cell features, leading to the loss of differentiation (anaplasia), and out-of-control cell growth and division (neoplasia). Apoptosis (programmed cell death) is often disrupted in cancer cells.

• Angiogenesis: Cancer cells grow blood vessels to support their own survival, a critical aspect of tumor growth.

• Cancer Detection: Early detection is crucial for successful treatment. Cancer can be diagnosed through various imaging techniques (mammography, MRI, CT scans, ultrasounds, endoscopy, nuclear medicine scans, PET scans) and analysis of substances, such as tumor markers (PSA, CEA).

• Causes and Risk Factors: Cancers influenced by hormonal factors (like synthetic estrogen), exposure to carcinogens (UV, radiation, chemicals including those in tobacco, dyes, pesticides, radon), genetics (BRCA gene), and lifestyle (diet, alcohol, smoking).

• Cancer Prevention and Treatment: Strategies include vaccinations (HPV, hepatitis B), controlling environmental exposures, maintaining a healthy weight, and avoiding known carcinogens. Prevention methods include regular screenings, early detection, and treatment of pre-cancerous growths. Secondary prevention (screening) and tertiary prevention (rehab) strategies are key. Treatments aim to reduce the tumor size.

Additional Notes

• Staging: Cancer staging systems (e.g., TMN) describe the size and extent of the tumor (tumor, nodes, metastasis). The higher the stage number, the more extensive the cancer.
• Grading: Tumor grading systems assess the degree of differentiation of cancer cells. Higher gradings usually indicate more aggressive behavior.
• Pathological Findings: A patient's overall medical history, physical exam, and imaging/lab tests influence detection and diagnosis of the presence, extent, and location of cancer. Assessment of appropriate body fluids is important (e.g., urine, blood).

Explore the characteristics that distinguish benign and malignant tumors, as well as the role of oncogenes in cancer development. Understand the differences in cell growth and the effects of cancer on normal cellular processes. This quiz will test your knowledge of oncology fundamentals as covered in week 12.