Untitled Quiz

Cancer Basics

• Cancer is defined as uncontrolled division of abnormal cells that invade surrounding tissues and evade normal cell cycle regulation and programmed cell death (apoptosis).
• Both genetic (non-modifiable) and environmental (modifiable) factors contribute to cancer development.

Cancer Epidemiology

• Cancer is the second leading cause of death in the U.S., with significant declines in mortality over the past 30 years attributed to scientific advancements.
• Most pronounced improvements in death rates have slowed compared to other chronic diseases.
• Higher mortality rates observed among men and African-Americans, indicating disparities influenced by social determinants of health.

TNM Staging System

• The TNM system assesses cancer severity through:
  • T (Tumor): Size and extent of the primary tumor (T0 = no tumor; Tis = carcinoma in situ; T1-4 = increasing size).
  • N (Node): Lymph node involvement (N0 = no involvement; N1-3 = increasing extent).
  • M (Metastasis): Presence of distant metastases (M0 = no metastasis; M1 = distant metastasis).
• Higher scores correlate with worse prognosis and influence treatment decisions.

Cancer Treatment

• Surgery: Primary treatment for diagnosis, staging, and tumor removal, often combined with other therapies to enhance effectiveness.
• Radiation Therapy: Utilizes ionizing radiation to target cancer cell DNA during mitosis; effective doses are measured in Gray (Gy).
  • Side effects can include fatigue, skin changes, and myelosuppression.
  • Ocular effects of radiation can vary significantly based on dosage; 25-30 Gy may cause minor damage, while 50+ Gy risks severe injury.

Ocular Effects of Radiation

• Common Complications:
  • Radiation retinopathy due to damage to vascular endothelial cells, leading to ischemia.
  • Symptoms can manifest between 1 month to 15 years post-treatment, with heightened risk between 6 months and 3 years.
  • Signs include microaneurysms, retinal hemorrhages, and vascular occlusions.

Chemotherapy

• Involves pharmaceuticals targeting specific phases of the cell cycle to halt cancer cell proliferation.
• Administered in various forms and can be combined with radiation or surgery.
• Common side effects include nausea, hair loss, myelosuppression, and mucositis.

Ocular Toxicity from Chemotherapy

• Chemotherapeutic agents can cause various ocular side effects including:
  • Corneal toxicity: keratitis, conjunctivitis.
  • Orbital toxicity: periorbital edema, inflammation, nasolacrimal duct obstruction.
  • Retinal and optic nerve toxicities: causing various retinal pathologies and possibly vision loss.

Other Types of Cancer Therapy

• Targeted Therapy: Utilizes drugs that focus on specific molecular mechanisms within cancer cells.
• Hormonal Therapy: Aims to inhibit hormone-driven tumors by blocking hormone receptors.
• Immunotherapy: Enhances immune system recognition and response to cancer cells.

Paraneoplastic Disease

• Occurs when malignancies induce autoimmune responses in other parts of the body, detectable via autoantibodies in blood or cerebrospinal fluid.
• Ocular effects can include bilateral diffuse uveal retinopathy and paraneoplastic optic neuropathy.

Cancer-Associated Retinopathy (CAR)

• Most prevalent ocular paraneoplastic condition linked with several cancers (e.g., small cell lung, breast).
• Symptoms typically include central vision loss, night blindness, and photophobia, with potential uveitis and retinal vasculitis observed on examination.

Clinical Pearls

• Detailed patient history should include cancer type, stage, treatment history, and remission status.
• Vigilance for signs of metastasis and paraneoplastic disease in all cancer patients is essential.
• Emergent referrals to oncology are warranted for patients exhibiting paraneoplastic symptoms without a current cancer diagnosis.