Lymphoma Study Guide

📖 Core Concepts Lymphoma – malignant tumors of lymphocytes (white‑blood cells) in the blood and lymphatic system. Two main categories – Hodgkin lymphoma (HL) (10% of cases) and non‑Hodgkin lymphoma (NHL) (90%). Reed‑Sternberg cell – the large, multinucleated cell that defines HL. “B” symptoms – fever, drenching night sweats, or ≥10 % weight loss in 6 mo; denote systemic disease. Ann Arbor staging – I–IV based on number of nodal regions and extranodal spread; each stage gets an A (no B‑symptoms) or B suffix. Risk factors – family history & EBV (HL); HIV, HTLV, autoimmune disease, immunosuppression, red‑meat intake, smoking (NHL). Diagnosis – excisional lymph‑node biopsy → histology + immunophenotyping/flow cytometry/FISH → imaging (CT, PET) for staging. Treatment pillars – chemotherapy (CHOP/R‑CHOP for aggressive NHL, ABVD for HL), radiation (localized HL), stem‑cell transplant (relapse), watchful waiting (indolent NHL). Prognosis drivers – lymphoma subtype, stage, patient age, performance status; high‑grade disease often curable with intensive chemo, low‑grade disease usually indolent but rarely cured. --- 📌 Must Remember 90 % NHL, 10 % HL. B‑symptom definition: fever ≥ 38 °C, night sweats, ≥10 % weight loss in 6 mo. Ann Arbor stages I = single region II = ≥2 regions same side of diaphragm III = both sides of diaphragm IV = extranodal organ involvement. Chemotherapy regimens CHOP = Cyclophosphamide, Doxorubicin, Vincristine, Prednisone. R‑CHOP = CHOP + Rituximab (CD20 + NHL). ABVD = Adriamycin, Bleomycin, Vinblastine, Dacarbazine (standard HL). Interim PET – negative → higher chance of complete remission; positive → higher risk of progression → consider therapy escalation. Nivolumab – checkpoint inhibitor effective in relapsed/refractory HL after autologous stem‑cell transplant; monitor for rash, colitis, thyroid issues. Watchful waiting – appropriate for asymptomatic, low‑grade (e.g., follicular) NHL. Prognostic factors – subtype, stage, age, performance status. --- 🔄 Key Processes Diagnostic Workflow Patient presents with painless lymphadenopathy ± B‑symptoms. Order CT (baseline staging). Perform excisional lymph‑node biopsy. Run immunophenotyping, flow cytometry, FISH to subtype. Stage with Ann Arbor (add PET for HL/FDG‑avid NHL). Staging (Ann Arbor) Steps Count involved nodal regions. Determine side of diaphragm (same vs both). Identify any extranodal organ disease → stage IV. Assess B‑symptoms → add “A” or “B”. Treatment Decision Algorithm Subtype + Stage + Grade → choose regimen. Aggressive NHL → CHOP ± Rituximab. HL → ABVD (early stage) or combined chemoradiation (advanced). Relapse → high‑dose chemo → autologous stem‑cell transplant. Indolent NHL & asymptomatic → watchful waiting. Interim PET Assessment Perform PET after 2–3 cycles of therapy. Negative → continue current plan. Positive → consider intensifying, switching regimen, or enrolling in trial. --- 🔍 Key Comparisons Hodgkin vs. Non‑Hodgkin HL: Reed‑Sternberg cells, 10 % of lymphomas, often PET‑avid. NHL: Heterogeneous group, no Reed‑Sternberg cells. CHOP vs. R‑CHOP CHOP: basic combo for aggressive NHL. R‑CHOP: adds Rituximab (anti‑CD20) – improves outcomes when CD20⁺. ABVD vs. BEACOPP ABVD: standard for most HL, lower toxicity. BEACOPP: more intensive, used for high‑risk or advanced HL. Aggressive vs. Indolent NHL Aggressive: rapid proliferation, needs immediate multi‑agent chemo. Indolent: slow growth, often managed with watchful waiting. PET‑negative vs. PET‑positive interim scan Negative: predicts higher remission rates. Positive: predicts higher progression risk, prompts therapy change. --- ⚠️ Common Misunderstandings All lymphomas present with B‑symptoms – many are painless, asymptomatic. PET always curative – PET is a diagnostic/prognostic tool, not a treatment. Rituximab works for every NHL – only CD20‑positive tumors benefit. Radiation alone cures advanced HL – advanced disease usually needs combined chemoradiation. Stage I = always localized and easy – stage I may still have systemic disease if B‑symptoms present. Watchful waiting is “no treatment” forever – treatment is initiated at disease progression. --- 🧠 Mental Models / Intuition “Lymphoma map” – picture the body split by the diaphragm; nodes on one side = Stage I‑II, both sides = Stage III, organ spread = Stage IV. B‑symptoms = “systemic fire” – if the patient’s “fire” (fever, sweats, weight loss) is lit, the disease is biologically more aggressive. PET as a “progress report card” – early scans tell you whether the current regimen is earning an “A” (negative) or a “D” (positive). CHOP → “standard engine”; add Rituximab when the car (tumor) has the CD20 “fuel gauge”. --- 🚩 Exceptions & Edge Cases CD20‑negative NHL – R‑CHOP is ineffective; alternative agents required. Non‑FDG‑avid NHL – PET may miss disease; rely more on CT and bone‑marrow studies. Immunodeficiency‑associated lymphomas – poorer prognosis, may need more aggressive therapy. Low‑grade NHL – can live near‑normal lifespan despite being incurable; quality‑of‑life considerations dominate. EBV‑positive HL – higher risk in patients with family history; may influence surveillance. --- 📍 When to Use Which Biopsy type – excisional (preferred) when possible; core needle only if surgery contraindicated. Imaging – CT for initial assessment; PET for HL and FDG‑avid NHL, especially for interim response. Chemo regimen – CHOP for aggressive NHL; add Rituximab if CD20⁺. HL first‑line – ABVD for early‑stage; BEACOPP or combined chemoradiation for advanced. Stem‑cell transplant – reserve for relapsed/refractory disease after standard chemo. Watchful waiting – asymptomatic, low‑grade (e.g., follicular) NHL. Nivolumab – relapsed/refractory HL after autologous transplant or when other options exhausted. --- 👀 Patterns to Recognize Painless lymphadenopathy + any B‑symptom → suspect lymphoma. Reed‑Sternberg cells on histology → HL. CD20 positivity on flow cytometry → candidate for Rituximab. Positive interim PET after 2 cycles → high risk of progression. History of HIV, HTLV, or immunosuppression → higher likelihood of NHL. Red‑meat intake & smoking history → risk factors for NHL. --- 🗂️ Exam Traps “Radiation alone cures all advanced HL” – false; advanced disease needs combined therapy. Choosing CHOP for follicular lymphoma without rituximab – most follicular lymphomas are CD20⁺; R‑CHOP or bendamustine + rituximab is preferred. Assuming PET‑negative = cure – PET only predicts early response, not guarantee of cure. Labeling any fever as a B‑symptom – fever must be ≥38 °C and unexplained; infection‑related fever is not a B‑symptom. Using staging “A/B” without checking for weight loss – missing weight loss leads to mis‑staging. Presuming all NHL are aggressive – many are indolent; treatment intensity differs. ---