Ppgl Metastatic Treatment Selection

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name: ppgl-metastatic-treatment-selection
description: Selects between CVD chemotherapy and radionuclide therapy as first-line systemic treatment for metastatic PPGL based on disease progression and imaging results. Triggers include PPGL with distant metastases requiring systemic therapy, assessing first-line treatment options for metastatic PPGL, and determining CVD chemo vs radionuclide therapy for progressive disease.
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# Metastatic PPGL Systemic Treatment Selection

## STEP 1 — Gather Information
Collect metastatic PPGL status: symptoms, catecholamine levels, imaging (123I-MIBG scintigraphy, somatostatin receptor scintigraphy, 18F-FDG PET if available), rate of disease progression (RECIST, tumor growth, symptom worsening), performance status, organ function (renal, hepatic, marrow), and availability/feasibility of radionuclide therapy.

## STEP 2 — Rule In / Rule Out
Is radionuclide therapy applicable (positive nuclear imaging on 123I-MIBG or somatostatin receptor scintigraphy and feasible to administer)? If NO → select CVD chemotherapy (decision). If YES → proceed to step 3.

## STEP 3 — Classify or Stratify
Assess disease progression rate: rapid progression (symptomatic worsening, RECIST progression, rising catecholamines) → choose CVD chemotherapy; slow/stable progression → choose radionuclide therapy (decision).

## STEP 4 — Decide
Initiate the selected systemic therapy: CVD chemotherapy (cyclophosphamide 750 mg/m2, vincristine 1.4 mg/m2, dacarbazine 600 mg/m2 every 21 days) or radionuclide therapy (131I-MIBG 5.55–7.4 GBq or 177Lu-DOTATATE 7.4 GBq per cycle with renal/thyroid protection).

## Clinical Guardrails / Mimics / Pitfalls
Do not use CVD chemotherapy when radionuclide therapy is feasible and disease is indolent due to lack of overall survival benefit and significant toxicity (bone marrow suppression, hypertensive crises). Do not rely solely on 123I-MIBG for radionuclide selection in SDHx-related PPGL; use somatostatin receptor imaging if MIBG negative. Avoid radionuclide therapy in patients with uncontrolled hypertension or severe marrow suppression. CVD chemotherapy does not improve overall prognosis; reserve for rapid progression or when radionuclide not applicable. Monitor for tumor lysis syndrome and hypertensive crises during CVD chemo.

## Concrete Clinical Example
A 58-year-old with metastatic PPGL to liver and bone, rising normetanephrine, and new lung nodules on CT (rapid progression). 123I-MIBG scintigraphy shows hepatic uptake but somatostatin receptor scan negative. Radionuclide therapy deemed not feasible due to negative somatostatin receptor imaging. CVD chemotherapy initiated; after two cycles, catecholamines decreased 60% and lung nodules stabilized.

**Source:** Japan Endocrine Society Clinical Practice Guideline for the Diagnosis and Management of Pheochromocytoma and Paraganglioma 2025, Japan Endocrine Society, 2025, doi:10.1507/endocrj.EJ25-0165