Endo Rt Residual Tumor If Med Unavail

Recommend radiation therapy for residual tumor when medical therapy unavailable/unsuccessful/not tolerated

STEP 1 — Gather Information

Obtain postoperative imaging (MRI preferred) at ≥12 weeks to assess residual tumor mass; review medical therapy history for availability, prior response, and tolerance; measure IGF-1 and GH if needed.

STEP 2 — Rule In / Rule Out

Is there a residual tumor mass on imaging? If no, consider disease controlled and radiation therapy not indicated. If yes, proceed to evaluate medical therapy suitability.

STEP 3 — Classify or Stratify

Is medical therapy unavailable, previously unsuccessful, or not tolerated? If yes, classify as radiation therapy candidate. If medical therapy is available, likely effective, and tolerated, classify as medical therapy candidate.

STEP 4 — Decide

For radiation therapy candidate, suggest conventional radiotherapy or stereotactic radiotherapy (SRT) per patient factors; for medical therapy candidate, initiate or optimize adjuvant medical therapy (SRL, pegvisomant, dopamine agonist).

Clinical Guardrails / Mimics / Pitfalls

Avoid radiation therapy if tumor is too close to optic chiasm (>8 Gy exposure); prefer SRT unless technique unavailable, significant residual tumor burden, or tumor near chiasm. Monitor annually for hypopituitarism after RT. Recognize that medical therapy may be needed while awaiting RT effect.

Concrete Clinical Example

A 45-year-old patient post‑transsphenoidal surgery has MRI‑confirmed residual tumor in the cavernous sinus and elevated IGF‑1. Octreotide LAR caused hyperglycemia and was discontinued; medical therapy unsuccessful/not tolerated. Recommend stereotactic radiotherapy given adequate optic chiasm distance.

Source: Acromegaly: An Endocrine Society Clinical Practice Guideline, Endocrine Society, 2014, DOI:10.1210/jc.2014-2700