Treatment/Prognosis Flashcards
What is the mainstay of Tx for chordomas?
Sg is the mainstay of Tx of chordomas, with studies demonstrating a direct correlation b/t the extent of surgical resection and the length of RFS. Definitive RT is an alternative and usually reserved for unresectable cases.
Why is intralesional excision for a vertebral body chordoma a suboptimal surgical Tx?
Intralesional excision has been shown to have a high rate of LR and to negatively affect OS. En bloc spondylectomy is preferred.
How are sacral amputations classified?
Based on the location of the highest level of nerve root sacrificed: low (sacrifice of at least 1 S4 nerve root or below), middle (sacrifice of at least 1 S3 nerve root), or high (at least 1 S2 nerve root). Total sacrectomy is performed when both S1 nerve roots are sacrificed.
What Tx is most commonly employed after surgical resection?
Most chordomas are not fully resectable and postop RT is often employed, even with a GTR.
Is aggressive management of chordomas at initial presentation (Sg + adj RT) important to improve outcomes compared to the same Tx at the time of recurrence (salvage RT)?
Yes. Adj RT may improve outcomes compared to a strategy of observation, reserving RT for salvage. A retrospective series from France (Carpentier A et al., J Neurosurg 2002) found that pts managed aggressively at initial presentation (Sg + RT) compared to those treated aggressively at the time of recurrence (after initial Sg) had improved outcomes (5- and 10-yr survival: 80% and 65% for aggressive vs. 50% and 0% for salvage).
Is there a role for neoadj RT?
A prospective phase II trial incorporating high-dose RT advocated for preop RT in addition to postop as it allowed for smaller volumes and reduced the risk of iatrogenic tumor seeding into the tumor bed. 1/23 primary chordomas recurred locally at a median f/u of 7.3 yrs. The findings favored a dose of ∼77.4 Gy RBE for primary tumors, and ∼70 Gy in the adj setting. (Delaney TF et al., J Surg Oncol 2014)
Is conventional fractionated photon RT an effective Tx for chordomas?
Yes. Conventional fractionated photon RT is effective for treating chordomas. Using image guidance, IMRT and median RT dose of 76 Gy in skull base chordomas, retrospective series from Toronto showed 5-yr LC rate of 65% and OS rate of 86% with acceptable toxicity rates. (Sahgal et al., Neuro Oncol 2015)
What is the role of SRS in the management of chordomas?
There is growing evidence supporting the role of SRS for chordoma. An MSKCC series that included unresectable pts reported a 95% LC rate at a median f/u of 24 mos with single fx SRS with a median dose of 24 Gy. (Yamada Y et al., Neurosurg 2013)
What other RT modalities can be utilized for skull base chordomas?
Proton beam, charged ion therapy and SRS have all been reported to control the tumor and improve cranial neuropathy.
What factor(s) determines the risk for recurrence after Tx with proton beam therapy?
In a series from Loma Linda, for residual tumors with brainstem involvement or volume >25 mL, the control rate was about 50% in the f/u period (mean, 33 mos); those not abutting the brainstem or <25 mL residual Dz did not have recurrence. (Hug EB et al., J Neurosurg 1999)
What is the pattern of recurrence of chordomas after Tx?
LR is most common (95%), with up to 40% of pts having both LR and DM. The most common sites of distant Dz are lung and bone. (Fagundes MA et al., IJROBP 1995; McPherson CM et al., J Neurosurg Spine 2006)
What is the typical LC and OS for chordomas compared to chondrosarcomas after 70 CGE of proton beam therapy?
In the Loma Linda series of 58 pts (33 chordomas and 25 chondrosarcomas), with a mean f/u of 33 mos, LC was 76% for chordoma and 92% for chondrosarcoma. The 5-yr OS rates were 79% for chordoma and 100% for chondrosarcoma. (Hug EB et al., J Neurosurg 1999)
What is the role of chemo or molecularly targeted agents in the management of chordomas?
Chordomas are generally not sensitive to chemo. However, PDGFR, EGFR, and mammalian target of rapamycin (mTOR) pathways have been implicated in the pathogenesis of chordomas. Small clinical series of targeted therapies have reported PRs and stable Dz in advanced pts (74% of pts experienced stable Dz with imatinib).
What is the survival of pts with recurrent Dz who rcvd salvage Tx compared to supportive care?
The outcomes after recurrence are generally poor, but salvage Tx (Sg + RT) can be used after recurrence, with 2-yr survival of 63% vs. 21% with supportive care. However, most pts die even with therapy, with 5-yr survival only 6% after recurrence. (Fagundes MA et al., IJROBP 1995)
Salvage therapy with proton or carbon ions may offer more effective LC over standard photon therapy. (Delaney TF et al., J Surg Oncol 2014; Uhl et al., Strahlenther Onkol 2014)
