Skip to content
How It Works
Explore
Resources Ask a Question
Who It's For
Patients
Decode results, prep for appointments, weigh options.
Caregivers & advocates
Carry the research load for someone you love.
Providers & clinicians
Resources for patients in your practice.
Log In Ask a Question
PubMed This is a summary of 18 peer-reviewed journal articles Updated
Neuro-oncology

Navigating Follow-Up: Pseudoprogression vs. True Recurrence

At a Glance

Pseudoprogression is a false sign of tumor growth on an MRI caused by inflammation from glioblastoma treatment. It typically occurs within 12 weeks of finishing radiation and often means the treatment is successfully killing cancer cells.

One of the most emotionally challenging parts of the glioblastoma journey is the first follow-up MRI after completing the Stupp protocol. It is common for a scan to look “worse”—showing more brightness or a larger area of enhancement—even when the patient feels fine. This phenomenon is known as pseudoprogression (PsP) [1][2].

What is Pseudoprogression?

Pseudoprogression is a “false” progression. It is a treatment-related inflammatory response where the radiation and chemotherapy have caused the blood vessels in the brain to become leaky and the surrounding tissue to swell [3]. On a standard MRI, this looks remarkably similar to a growing tumor, but it is actually a sign that the treatment is working to kill cancer cells [1].

  • Timing: Pseudoprogression most typically occurs within the first 3 months (12 weeks) after finishing radiation therapy [4][5].
  • The MGMT Connection: Interestingly, patients with MGMT-methylated tumors are more likely to experience pseudoprogression [6][7]. Because methylated tumors are more sensitive to chemotherapy, they often have a more intense inflammatory reaction as the cancer cells die off [3].

How Doctors Tell the Difference

Because pseudoprogression and true progression (actual tumor growth) look so much alike on a regular MRI, your neuro-oncologist will use several tools to differentiate them:

  1. Clinical Symptoms: Pseudoprogression is often “silent,” meaning the scan looks worse but you feel the same. If you are experiencing new or worsening neurological symptoms, doctors are more likely to suspect true progression [8][9].
  2. Advanced Imaging: Your team may order specialized scans to look beneath the surface:
    • Perfusion MRI (DSC/DCE): Measures blood flow. A true tumor needs lots of blood to grow, while pseudoprogression (inflammation) typically shows lower blood volume [10][11].
    • Diffusion-Weighted Imaging (DWI): Measures how water molecules move. Densely packed tumor cells restrict water movement more than the swelling seen in PsP [12][13].
    • MR Spectroscopy (MRS): Analyzes the chemical “signature” of the area to look for tumor-specific metabolites.
  3. The “Wait and See” Approach (RANO 2.0): Doctors follow standardized guidelines called RANO (Response Assessment in Neuro-Oncology). If a scan looks worse shortly after radiation and the patient is stable, the guidelines often recommend continuing the current treatment and repeating the scan in 4 to 8 weeks to see if the changes stabilize or disappear [14][15].

Managing “Scanxiety”

It is completely normal to feel intense anxiety—often called scanxiety—before and after these appointments. Finding out that a scan looks “larger” can be devastating, but in the early months of treatment, it is often a sign of the “battle” taking place in the brain.

While advanced imaging is helpful, pathological confirmation (a second biopsy) remains the only 100% certain way to tell the difference in ambiguous cases, though doctors try to avoid this unless absolutely necessary [16][17]. Most of the time, patience and follow-up imaging provide the clarity needed to stay the course [18].

Common questions in this guide

What is pseudoprogression in glioblastoma?
Pseudoprogression is a false appearance of tumor growth on an MRI caused by inflammation and swelling from radiation and chemotherapy. It actually indicates that the treatment is working to kill cancer cells, despite how the scan looks.
How soon after treatment does pseudoprogression happen?
It typically occurs within the first three months, or 12 weeks, after finishing radiation therapy. During this window, inflammatory MRI changes are highly common and expected.
How do doctors tell the difference between pseudoprogression and true tumor growth?
Doctors assess whether you have new neurological symptoms and use advanced scans like Perfusion MRI to measure blood flow. True tumors require high blood flow to grow, while treatment-related inflammation typically shows lower blood volume.
Does my MGMT methylation status affect my MRI results?
Yes, patients with an MGMT-methylated tumor are more likely to experience pseudoprogression. Because these tumors are highly sensitive to chemotherapy, they often trigger a stronger inflammatory reaction as the cancer cells die.
What is the next step if my scan shows possible pseudoprogression?
If your symptoms are stable, doctors typically follow standardized guidelines and recommend a 'wait and see' approach. You will likely continue your current treatment and have a repeat scan in 4 to 8 weeks to check if the changes stabilize or disappear.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Given that I finished radiation less than 12 weeks ago, could these MRI changes be pseudoprogression rather than true growth?
  2. 2.How does my MGMT methylation status affect the likelihood that this is a treatment effect?
  3. 3.Are you using advanced imaging like Perfusion MRI or MR Spectroscopy to look at the blood flow and chemistry in this area?
  4. 4.If we are following RANO 2.0 criteria, should we wait for a confirmatory scan in a few weeks before changing my treatment?
  5. 5.Since I am not feeling any new symptoms, does that make it more likely that the scan is showing a 'false' progression?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (18)
  1. 1

    Response Assessment in Neuro-Oncology Clinical Trials.

    Wen PY, Chang SM, Van den Bent MJ, et al.

    Journal of clinical oncology : official journal of the American Society of Clinical Oncology 2017; (35(21)):2439-2449 doi:10.1200/JCO.2017.72.7511.

    PMID: 28640707
  2. 2

    Neuroimaging of Brain Tumors: Pseudoprogression, Pseudoresponse, and Delayed Effects of Chemotherapy and Radiation.

    Dietrich J, Winter SF, Klein JP

    Seminars in neurology 2017; (37(5)):589-596 doi:10.1055/s-0037-1608657.

    PMID: 29207418
  3. 3

    The value of MGMT promote methylation and IDH-1 mutation on diagnosis of pseudoprogression in patients with high-grade glioma: A meta-analysis.

    Zhou M, Niu C, Jia L, He H

    Medicine 2019; (98(50)):e18194 doi:10.1097/MD.0000000000018194.

    PMID: 31852075
  4. 4

    Differentiation of tumor progression from pseudoprogression in glioblastoma patients with GRASP DCE-MRI and DSC-MRI.

    Var V, Leu SM, Rommers N, et al.

    Journal of neuroradiology = Journal de neuroradiologie 2025; (52(4)):101354 doi:10.1016/j.neurad.2025.101354.

    PMID: 40419180
  5. 5

    Amide proton transfer-weighted (APTw) CEST MRI in clinical routine for single time point diagnosis of pseudoprogression in IDH-wildtype glioblastoma.

    Zeyen T, Krause I, Decker A, et al.

    Neuro-oncology 2026; (28(3)):790-801 doi:10.1093/neuonc/noaf261.

    PMID: 41233976
  6. 6

    Different diagnostic values of imaging parameters to predict pseudoprogression in glioblastoma subgroups stratified by MGMT promoter methylation.

    Yoon RG, Kim HS, Paik W, et al.

    European radiology 2017; (27(1)):255-266 doi:10.1007/s00330-016-4346-y.

    PMID: 27048531
  7. 7

    Pseudoprogression as an adverse event of glioblastoma therapy.

    Balaña C, Capellades J, Pineda E, et al.

    Cancer medicine 2017; (6(12)):2858-2866 doi:10.1002/cam4.1242.

    PMID: 29105360
  8. 8

    Clinical and radiological features of pseudoprogression in brain tumors treated with immune checkpoint inhibitors.

    Ibáñez-Juliá MJ, Bataller L, Cabello-Murgui FJ, et al.

    Journal of neuro-oncology 2025; (174(3)):779-788 doi:10.1007/s11060-025-05091-0.

    PMID: 40426008
  9. 9

    Pseudoprogression in lung cancer patients treated with immunotherapy.

    Chen MY, Zeng YC

    Critical reviews in oncology/hematology 2022; (169()):103531 doi:10.1016/j.critrevonc.2021.103531.

    PMID: 34800651
  10. 10

    Perfusion MRI in treatment evaluation of glioblastomas: Clinical relevance of current and future techniques.

    van Dijken BRJ, van Laar PJ, Smits M, et al.

    Journal of magnetic resonance imaging : JMRI 2019; (49(1)):11-22 doi:10.1002/jmri.26306.

    PMID: 30561164
  11. 11

    The Value of Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) in the Differentiation of Pseudoprogression and Recurrence of Intracranial Gliomas.

    Jing H, Yan X, Li J, et al.

    Contrast media & molecular imaging 2022; (2022()):5680522 doi:10.1155/2022/5680522.

    PMID: 35935318
  12. 12

    Early progressive disease within 2 years in isocitrate dehydrogenase (IDH)-mutant astrocytoma may indicate radiation necrosis.

    Ozeki Y, Honda-Kitahara M, Yanagisawa S, et al.

    Japanese journal of clinical oncology 2025; (55(2)):106-112 doi:10.1093/jjco/hyae151.

    PMID: 39660448
  13. 13

    The Role of Apparent Diffusion Coefficient Values in Glioblastoma: Differentiating Tumor Progression Versus Treatment-Related Changes.

    Kamali A, Gandhi A, Nunez LC, et al.

    Journal of computer assisted tomography 2022; (46(6)):923-928 doi:10.1097/RCT.0000000000001373.

    PMID: 36112011
  14. 14

    RANO 2.0: critical updates and practical considerations for radiological assessment in neuro-oncology.

    Sakata A, Fushimi Y, Oshima S, et al.

    Japanese journal of radiology 2025; (43(10)):1557-1574 doi:10.1007/s11604-025-01821-6.

    PMID: 40586994
  15. 15

    RANO 2.0: Update to the response assessment for gliomas.

    Pineda Ibarra C, Oleaga Zufiria L, Valduvieco Ruiz I, et al.

    Radiologia 2025; (67(4)):101621 doi:10.1016/j.rxeng.2025.101621.

    PMID: 40675718
  16. 16

    Pseudoprogression after glioma therapy: an update.

    Galldiks N, Kocher M, Langen KJ

    Expert review of neurotherapeutics 2017; (17(11)):1109-1115 doi:10.1080/14737175.2017.1375405.

    PMID: 28862482
  17. 17

    Perioperative imaging predictors of tumor progression and pseudoprogression: A systematic review.

    Librizzi G, Lombardi G, Bertoldo A, Manara R

    Critical reviews in oncology/hematology 2024; (202()):104445 doi:10.1016/j.critrevonc.2024.104445.

    PMID: 38992848
  18. 18

    RANO 2.0 criteria: concepts applicable to the neuroradiologist's clinical practice.

    Sanvito F, Castellano A, Cloughesy TF, et al.

    Current opinion in oncology 2024; (36(6)):536-544 doi:10.1097/CCO.0000000000001077.

    PMID: 39011735

This page explains glioblastoma MRI follow-up concepts for educational purposes only. Always consult your neuro-oncologist for interpretation of your specific brain scans and treatment decisions.

Get notified when new evidence is published on Glioblastoma.

We monitor PubMed for new peer-reviewed studies on this topic and email a short summary when something meaningful changes.