Radiation Oncology/CNS/Trigeminal neuralgia/Retreatment

Trigeminal Neuralgia Retreatment

Gamma Knife Retreatment

• San Diego Gamma Knife Center 2006 NSA Abstract -- "Dose response of Gamma Knife surgery for trigeminal neuralgia and high-dose salvage of failed Gamma Knife surgery" (Ott K, Neurosurgical Society of America Abstract, 2006)
  • Retrospective. 263 patients treated, 26 retreated. RT dose range 26-140 Gy. Average f/u 32 months
  • Pain control: Typical TN 85% excellent/good, Atypical TN 46% excellent/good. Dose response present, now use 97 Gy for both treatment and retreatment.
  • Side effects: >50% facial numbness, usually transient. Better pain control results
  • Retreatment: Same benefit. Comparable facial numbness, better response. Some with fair/poor/no response initially had excellent response on retreatment

• Columbia
  • 2005 PMID 15850900 -- "Where to locate the isocenter? The treatment strategy for repeat trigeminal neuralgia radiosurgery." (Zhang P, Int J Radiat Oncol Biol Phys. 2005 May 1;62(1):38-43.)
    • Retrospective. 40 patients with repeat GK. RT max 75 Gy initially, 40 Gy retreatment. Median f/u 28 months
    • Pain relief: complete 27%, nearly complete 18%, partial 20%, minimal/none 35%
    • Isocenter distance: mean 2.86 mm (complete/nearly complete relief) vs. 1.93 (partial/none relief). Farther distance with trend to better pain relief
    • Side effects: 7% moderate dysesthesia (4+/10), 3% severe dysesthesia (7+/10) after retreatment. Not related to isocenter distance
  • 2003 PMID 14742963 1998-2003 -- "Repeat gamma knife radiosurgery for trigeminal neuralgia." (Brisman R, Stereotact Funct Neurosurg. 2003;81(1-4):43-9.)
    • Retrospective. 335 patients treated to 75 Gy, 45 patients retreated with 40 Gy. Mean 15 months f/u
    • Final pain relief: >50% in 62%. If no prior neurosurgical procedure, more likely to have better pain relief
    • Side effects: significant dysesthesias (>5/10) in 2 patients (4%)

• Prague (Czech)
  • 2005 PMID 15662776 -- "Treatment of essential trigeminal neuralgia with gamma knife surgery." (Urgosik D, J Neurosurg. 2005 Jan;102 Suppl:29-33.)
    • Retrospective. 107 patients, retreat in 19 patients, same dose. RT 70-80 Gy.
    • Pain relief: Initial 96% (complete 80%). Median time to improvement 3 months (1 day, 13 months). Recurrence 25%, median interval 36 months (6, 94).
    • Retreatment: 19 patients (17%), initial pain relief 89% (complete 58%). Relapse 1 patient thus far
    • Side effects: Hypesthesia 20% after first GK, 32% after second GK. Median interval 35 months (3, 94) after first GK, 21 months (1, 72) after second

• Mayo
  • 2005 PMID 15629611 1997-2002 -- "Repeat radiosurgery for idiopathic trigeminal neuralgia." (Pollock BE, Int J Radiat Oncol Biol Phys. 2005 Jan 1;61(1):192-5.)
    • Retrospective. 19 patients retreated. Median interval 16 months. Median dose 76.1 Gy (median additive dose 163.1 Gy). Median f/u 24 months
    • Pain relief: 74% excellent, 95% >50% pain reduction. 61% excellent outcome at 2 years. 2 patients recurred at 7, 22 months.
    • Side effects: 58% facial parathesia, numbness or dyesthesia, 16% bothersome. 2 patients (11%) corneal numbness. Recommend reducing dose
  • 2000 PMID 11143237 1997-1999 -- "Results of repeated gamma knife radiosurgery for medically unresponsive trigeminal neuralgia." (Pollock BE, J Neurosurg. 2000 Dec;93 Suppl 3:162-4.)
    • Retrospective. 10 patients retreated. Median interval 13 months. All initially significant reduction, none with facial numbness
    • Pain relief: 80% excellent outcome at 1 year. All developed minor dysfunction

• Maryland
  • 2005 ASTRO Abstract 1996-2004 -- "Comparison of Repeat GK-SRS for Refractory or Recurrent Trigeminal Neuralgia: Does Dose Matter" (Dutta PR, Abstract 2118)
    • Retrospective. 63/69 patients (Maryland 28, Kentucky 35).
    • Maryland:
      • First GKS RT median 75 Gy (70-80 Gy), second GKS 70 Gy (45-75 Gy). Median retreatment in 13 months. Median f/u 14 months
      • Pain control: Initially 43% excellent, 43% good. Retreatment 39% excellent, 43% good. All 3 with initially poor response did not respond to retreatment
      • Side effects: 25% new after 2nd GKS, total 43% numbness; 14% bothersome but had complete relief
    • Kentucky
      • First GKS median 90 Gy (80-90 Gy), second GKS 90 Gy (70-90 Gy). Median f/u 19 months
      • Pain control: initially 33% excellent, 22% good. Retreatment 64% excellent, 20% good. Of 8 with poor response, 50% excellent result after retreatment
      • Side effects: 25% new after 2nd GKS, total 33% numbness or dysesthesia. 3% bothersome
    • Conclusion: Cumulative dose 150 Gy vs. 180 Gy. Similar pain control, but 180 Gy more likely to have excellent outcome. Minimal bothersome effects.
  • 2004 1996-2001 PMID 15093906 -- "Repeat gamma knife radiosurgery for refractory or recurrent trigeminal neuralgia: treatment outcomes and quality-of-life assessment." (Herman JM, Int J Radiat Oncol Biol Phys. 2004 May 1;59(1):112-6.)
    • Retrospective. 112 treated, 18 underwent repeat GKS. Median 8 months (3-42 months). Median RT 75 Gy first GKS, 70 Gy second GKS. Median f/u 37 months after first GKS, 24 months after second GKS
    • Pain control: Excellent 50%, good 28%, fair 6%, poor 16%. None of initial failures responded to repeat GKS
    • Side effects: 2 patients (11%) facial numbness, 1 bothersome
  • 2003 ASTRO Abstract -- "Repeat Gamma Knife Radiosurgery for Refractory or Recurrent Trigeminal Neuralgia" (Petit H, Abstract 22, 2003). Full paper Herman 2004 above

• Barrow Neurological Institute; 2002 1997-2002 PMID 12507092 -- "Gamma knife radiosurgery for recurrent trigeminal neuralgia." (Shetter AG, J Neurosurg. 2002 Dec;97(5 Suppl):536-8.)
  • Retrospective. 19/29 patients. Questionnaires. Initial RT dose mean 78.2 Gy (70-90). RT retreatment mean dose 46.6 Gy (35-80). Mean f/u 13.5 months
  • Pain control: 53% excellent, 21% pain free but on reduced meds
  • Side effects: Facial numbness 42%, none bothersome. Those with facial numbness greater likelihood of being pain free

• Pittsburgh 2002 PMID 11841716 -- "Repeat radiosurgery for refractory trigeminal neuralgia." (Hasegawa T, Neurosurgery. 2002 Mar;50(3):494-500; discussion 500-2.)
  • Retrospective. 27/31 patients assessed. Median dose 75.6 Gy (60-80 Gy), retreatment 64 Gy (50-80 Gy). Median f/u 43 months after 1st GKS, 20 months after 2nd GKS.
  • Pain control: 18% excellent, 30% good, 37% fair, 15% poor. Overall 48% complete pain relief (with or without meds)
  • Dose-response: low dose (120-135 Gy) vs. high dose (140-160 Gy): NS, although slightly fewer excellent and slightly more good outcomes with low dose. Now deliver 50-60 Gy)
  • Side effects: 13% dysfunction

• Tianjin 2001 (China) 1996-1999 PMID 12007276 -- "Stereotactic radiosurgery for primary trigeminal neuralgia using the Leksell Gamma unit." (Zheng LG, Stereotact Funct Neurosurg. 2001;76(1):29-35.)
  • Retrospective. 80 patients. RT dose mean 75.6 Gy (70-90 Gy). Follow-up 24 months
  • Pain control: excellent 52%, good 31%, fair 10%, fail 6%. Mean time to improvement 22 days (1-120 days). Recurrence 10% in 5-26 months later
  • Retreatment: 12 patients (7 recurrent, 5 failures). RT dose mean 74.2 Gy (70-80 Gy). Mean f/u 18 months, 9/12 excellent result, 2/12 good result, 1 failed. Mean time to improvement 15 days (1-120)
  • Side effects: 11% facial numbness

• Norhtwest Hospital 2000 Abstract 1991-1999 -- "Gamma Knife radiosurgery for treatment of trigeminal neuralgia: long term results" (Young RF, 3rd TN Conference, 2000)
  • Retrospective. 435 patients. RT 76-98 Gy. Median f/u 51 months. 51 patients retreated. Joint with Good Samaritan data??
  • Pain control: 6 months - 60% excellent, 30% good (some meds). Last f/u - 78% excellent/good. Including retreatment, 65% excellent, 20% good
  • Retreatment: success 80%
  • Side effect: 16% facial numbness