Temodal (Temozolomide) Treatment Regimen With Concurrent Radiotherapy
Reading tools
In this article
Glioblastoma multiforme (GBM)is the most common and most aggressive primary brain tumor in adults. Standard treatment after surgical resection consists of temozolomide (Temodal) with concurrent radiotherapy followed by adjuvant temozolomide cycles. This approach is known in the literature as the Stupp protocol and is currently accepted in international guidelines as the gold standard .
Definition and Mechanism of Action
Temozolomide (Temodal)is an oral alkylating agent derived from imidazotetrazine. In the body, it spontaneously converts to the metabolite MTIC (monomethyltriazenoimidazole carboxamide) and adds a methyl group at the DNA O6-guanine position. This change causes DNA mismatches and apoptosis. When used with radiotherapy, DNA repair mechanisms are suppressed, producing a radiosensitizing effect .
Clinical Evidence
Stupp et al., NEJM 2005:
- 573 patients with newly diagnosed glioblastoma (postoperative RT ± Temozolomide).
- Median survival: 12.1 months in the RT arm, 14.6 months in the RT+Temozolomide arm.
- 2-year survival rate: 26% (combination) vs 10% (RT alone).
- Greatest benefit: MGMT methylation-positive patients.
Treatment Goals
- Improve radiotherapy efficacy and make DNA damage permanent
- Slow tumor growth and progression
- Prolong survival, particularly in younger patients with good performance status
- Preserve quality of life (maintain neurological function)
Role in Guidelines
NCCN (2025), EANO (2021), ASCO guidelines recommend:
- For newly diagnosed glioblastoma, the standard approach is surgery + RT (60 Gy/30 fractions) + concurrent temozolomide (75 mg/m²/day), followed by 6 cycles of adjuvant temozolomide.
- In older patients with poor performance status (KPS <60), abbreviated RT + concurrent/temozolomide alone may be an option.
Temozolomide With Concurrent Radiotherapy
The concomitant phaseinvolves daily temozolomide given concurrently with postoperative radiotherapy. This approach forms the basis of the Stupp protocol .
Standard Dose
- Dose: 75 mg/m²/day
- Route: Oral, capsule form
- Frequency: Every day (including weekends), without interruption
- Duration: Throughout radiotherapy (usually 6 weeks, a total of 42 days)
Timing of Administration
- Temozolomide is generally recommended 1 hour before the radiotherapy session → so that plasma levels approach their maximum during RT.
- Capsules must not be opened or chewed; they should be swallowed whole .
- Taking it on an empty stomach increases bioavailability and may reduce nausea.
Follow-Up and Monitoring
- Blood count: During RT + Temozolomide, perform 1 complete blood count per week.
- Liver function tests: 1 test every 2 weeks is recommended.
- PCP (Pneumocystis jirovecii pneumonia) prophylaxis: Should be considered particularly in patients receiving prolonged corticosteroids.
Criteria for Treatment Interruption / Delay
- Absolute neutrophils <1.5 ×10⁹/L or Platelets <100 ×10⁹/L → Temozolomide is stopped.
- Treatment is interrupted until toxicity resolves and may then be resumed at the same dose.
- If Grade 3–4 toxicity develops → treatment should be discontinued; restarting requires a multidisciplinary decision.
Managing Nausea and Vomiting
- Temozolomide is moderately emetogenic.
- Recommendation: Before the daily dose, 5-HT3 antagonists (e.g., ondansetron) should be started.
- Metoclopramide or NK1 antagonists may be added for refractory nausea.
Practical Administration Points
- When rounding capsule doses, select the closest combination (5–250 mg strengths are available).
- If vomiting occurs → do not take an additional dose that day.
- Missed dose → may be taken if remembered the same day; the next day, do not take a double dose.
- When preparing and administering the drug, healthcare personnel should wear gloves.
Drug Interactions
- Valproic acid: May reduce Temozolomide clearance; hematological toxicity increases.
- Co-trimoxazole: May be needed for Pneumocystis jirovecii prophylaxis, but may increase bone marrow suppression.
- Hepatotoxic drugs: Increase hepatotoxicity risk.
- Antiepileptics such as phenytoin and carbamazepine: May alter Temozolomide metabolism.
Special Situations
- Older patients: Myelotoxicity may be more common.
- Renal impairment: No problem in mild/moderate impairment, but caution is needed in severe impairment.
- Hepatic impairment: Adjust the dose carefully in Child-Pugh C.
- Infection risk: Consider prophylactic PCP prophylaxis (e.g., TMP-SMX).
Side Effects and Management
| Side Effect | Frequency | Management |
|---|---|---|
| Neutropenia / Thrombocytopenia | 20–30% | Dose delay, G-CSF, transfusion |
| Nausea / Vomiting | 30–40% | Prophylactic antiemetic, small frequent meals |
| Hepatotoxicity | 5–10% | LFT monitoring, temporary interruption |
| Fatigue | 40%+ | Sleep hygiene, light exercise |
| Opportunistic infection | 5–7% | PCP prophylaxis, close monitoring |
Dose Modification
- Neutrophils <1.5 ×10⁹/L or Platelets <100 ×10⁹/L: Delay the dose.
- Grade 3–4 hematological toxicity: Reduce the dose by 25% in the next cycle.
- Grade ≥3 hepatotoxicity: Discontinue the drug; restarting requires a multidisciplinary decision.
Advice for Patients
- Take your medicine at the same time every day, preferably on an empty stomach.
- Be sure to take anti-nausea medicines (e.g., ondansetron) if prescribed by your physician.
- Seek emergency care if fever, sore throat, bleeding or bruising develops.
- Avoid crowds and maintain good hygiene to protect against infections.
- Must never be used during pregnancy or breastfeeding.
- Consult your doctor first if you are considering herbal products or supplements.
References
- Stupp R, et al. Radiotherapy plus concomitant and adjuvant temozolomide for glioblastoma. N Engl J Med. 2005;352:987–996. doi:10.1056/NEJMoa043330
- NCCN Guidelines Central Nervous System Cancers. Version 2.2025
- Weller M, et al. EANO guidelines on the diagnosis and treatment of adult gliomas. Lancet Oncol. 2021;22(8):e391–e403.
- ASCO Guidelines: Treatment of newly diagnosed glioblastoma. J Clin Oncol. 2020;38(25):e150–e168.
- Perry JR, et al. Short-course radiation plus temozolomide in elderly patients with glioblastoma. N Engl J Med. 2017;376:1027–1037.
Was this article helpful?
Your feedback helps us improve our content.
Reader comments
Share your comment
Your name and comment are published only after administrator approval. Your email address is never shown to visitors.
Be the first to comment.