Treatment/prognosis Flashcards
Options for AN in patients?
obeservation, surgery, or radiation
when is observation appropriate?
what follow-up do you need for observation?
- small tumors < 2cm or no/slow growth w/o progression
- 43% with growth, 51% stable, 6% regressed w/o treatment
- Smouha EE et al. Laryngoscope 2005
- For followup- audiometry and MRI scans q 6-12 mo
4 Surgical approaches available for ANs and what are the prominent advantages and disadvantages?
- Retromastoid: may not be able to achieve GTR/ good facial nerve preservation, good hearing preservation, can be used for any size tumor
- Middle cranial fossa: GTR, facial nerve preservation moderate-hearing preservation better, good for small < 1.5-cm tumors
- Translabyrinthine: sacrifices hearing/ good facial nerve preservation, recommended if tumor > 3 cm
- Retrolabyrinthine: sacrifices hearing
When is surgery the preferred option?
when tumor >4cm symptomatic tumors or recurrence/progression after RT
Recurrence rates after GRT for ANs?
Overall facial and hearing preservation after surgery for AN?
- <1%
- 80-90% facial preservation rate and 50% hearing preservation rate
What are facial nerve and hearing preservation rates after RT for ANs? (SRS and fractionated)
- SRS
- Facial nerve preservation rate >95%
- Hearing preservation is 70-90%
- Fractionated
- Facial nerve preservation rate ~95%
- Hearing preservation is 55-65%
Long term LC rates after RT for AN
- Long-term LC after RT for ANs is 90%– 97%.
- (Lunsford LD et al., J Neurosurg 2005; Combs SE et al., IJROBP 2006; Litre F et al., Radiother Oncol 2013; Hasegawa T et al., J Neurosurg 2013; Maniakas A et al., Otol Neurotol 2012)
- what are commonly used doses for SRS/Gamma Knife SRS for ANs
- What has been a trend for the tx of ANs with SRS?
- 12 -13 Gy to 50% IDL is commly used SRS
- lowered from 16 Gy to 12-13 Gy as Pittsburgh and Japanese data that showed similar LC rates but less facial weakness and hearing loss with lower doses
What doses are used for Fractionated SR?
Hearing preservation rates with Fractionated SR
- 50-55 Gy (25-30 fx at 1.8 Gy fractions) if larger > 2-3cm
- Alternative 25 Gy (5x5) for smaller lesions
- Controversal hearing preservation
- Thought to be better with FSR thatn SRS or surgery (94% in Combs SE, IJROP 2005, 81% in Andrews DW et al IJROP 2001)
- Other studies suggest similar outcomes if <13 Gy (Combs SW et al IJROP 2011)
What data suggets that hearing preservation is better with similar LC rates with lower dose fractionated RT therapy?
- Thomas Jefferson
- 46.8 Gy vs. 50.4 Gy had 100% LC at 5 years w/ better hearing preservation rate
- Raw 3-year hearing preservation 46.8 Gy 79% vs. 50.4 Gy 68% (SS). P
What other RT modalities have been successfully employed in AN
- CyberKnife (Chang SD et al., J Neurosurg 2005) and protons (Weber DC et al., Neurosurg 2003; Vernimmen FJ, Radiother Oncol 2009):
- worse hearing preservation (not used with tumors > 2 cm and if pt can hear well)
SRS vs. Surgery which Studies were compared and what did they show
- Mayo Clinic data: < 3-cm tumors, same tumor control rates but worse pt QOL after surgery. (Pollock BE et al., J Neurosurg 2006)
- French data: largest prospective study. GK pts had better function overall. (Regis J et al., Neurochirurgie 2002)
- Meta-analysis: included 16 studies showed SRS better long-term hearing preservation (70% vs. 50%) but no difference in tumor outcome. (Maniakas A and Saliba I, Otol Neurotol 2012)
What AN study prospectively evaluated SRS vs. FSR?
- Dutch data: dentate pts rcvd FSR (20– 25 Gy in 5 fx) and edentate SRS (10– 12.5 Gy), with similar LC and functional outcomes. (Meijer OW et al., IJROBP 2003)
What agent has recently been shown to be effective in NF-2 pts with refractory ANs?
- Bevacizumab (Avastin) was recently shown to be effective in NF-2 pts with refractory ANs. (Plotkin SR et al., NEJM 2009)
Dose falloff to which structures need to be evaluated with GK SRS for ANs?
Cochlea and brainstem
