Treatment/Prognosis Flashcards
What modalities are used to treat SC compression?
Modalities used to treat SC compression: steroids, Sg, and RT (in select cases chemo is used for chemosensitive tumors)
What is the initial management of cord compression?
For initial management of cord compression, start dexamethasone (include GI prophylaxis with proton-pump inhibitor or H2 blocker) and consult neurosurgery or orthopedics, depending on the institution, to assess spine stability. If there is any concern for a hematologic malignancy without Bx proof, stat multidisciplinary discussion is needed before starting steroids to consider whether to Bx first.
What initial bolus dose of dexamethasone should be used in cord compression?
For newly diagnosed cord compression, a loading dose of 10 mg IV is generally given → 4 mg orally q6hrs. Vecht CJ et al. randomized 37 pts to 10 mg IV vs. 100 mg IV, both → 16 mg daily in divided oral doses. There was no difference in pain control, rate of ambulation, or bladder function. (Neurology 1989) In practice, a higher loading dose of 20 mg IV dexamethasone can be considered in cases of severe neurologic dysfunction.
Historically, what type of Sg was used to treat SC compression?
Historically, laminectomy was used to treat SC compression. However, this was abandoned b/c it can lead to instability, and improved surgical stabilization techniques have allowed for ant decompressive approaches.
What pts with cord compression are appropriate for decompressive Sg?
Pts with MRI evidence of cord compression in a single area and a life expectancy >3 mos who do not have radiosensitive tumors (lymphomas, leukemias, germ cell tumors, and multiple myeloma) may be good candidates for decompressive Sg → RT. (Patchell R et al., Lancet 2005)
What are further indications for Sg?
Spinal instability and/or bony retropulsion, previous RT, Dz progression despite RT, unknown primary tumor (therapeutic and diagnostic), paraplegia <48 hrs
What was the trial design and outcome of the Patchell study of decompressive Sg for cord compression?
The Patchell cord compression trial was a multi-institutional RCT of 101 pts with MRI-confirmed SC compression restricted to a single area with >3-mo life expectancy. Exclusion criteria included being paraplegic >48 hrs, radiosensitive tumors, Hx of prior cord compression, and other pre-existing neurologic conditions. Pts were randomized to decompressive Sg + RT vs. RT alone. RT was 30 Gy/10 delivered to the lesion + 1 vertebral body above and below. Sg was tailored to the individual lesion to provide circumferential decompression and stabilization as needed (ant corpectomy for 60% of cases involving only the vertebral body). The study was stopped at interim analysis. Sg significantly improved the ambulatory rate (84% vs. 57%), duration of ambulatory status (122 days vs. 13 days), and survival (126 days vs. 100 days). Pts nonambulatory prior to Tx were more likely to walk after Sg (62% vs. 19%). (Patchell R et al., Lancet 2005)
What are some criticisms of the Patchell data?
RT alone results were worse than historical prospective controls, small sample size, 18 pts in the RT alone group had an “unstable” spine, Sg provides immediate decompression in pts with rapid onset of Sx (delayed response with RT).
Can Sg be delayed following RT?
Due to a decline in neurologic function (nonambulatory), 10 pts in the RT group (20%) underwent Sg; 3 regained the ability to walk (30%) with results inf to Sg upfront.
Is SBRT utilized for primary Tx of cord compression?
No. Although ASTRO guidelines suggest that SBRT can be considered as part of a clinical trial or prospective registry, direct tumor contact with the SC (epidural compression within 3 mm) and/or spinal instability are considered contraindications to SBRT.
What pts with cord compression should be treated with RT alone?
Cord compression pts treated with RT alone: life expectancy <3 mos, no spinal instability or bony compression, multilevel involvement and radiosensitive tumor
Estimate the survival for a pt with metastatic SC compression.
Rades et al. reviewed 1,852 pts with cord compression and found that survival depends on 6 factors. Validated in a series of 439 pts, they developed a scoring system that includes:
– tumor histology (myeloma/lymphoma = 9, breast = 8, prostate = 7, other = 4, lung = 3)
– Dx to metastatic cord compression (>15 mos = 7, ≤15 mos = 4)
– additional visceral mets (no = 8, yes = 2)
– additional bone mets (no = 7, yes = 5)
– ability to ambulate (yes = 7, no = 3)
– days since the development of motor deficits (>14 = 8, 8–14 = 6, ≤7 = 3)
6-mo OS by score was:
– 36–45 points: 80%
– 31–35 points: 56%
– 20–30 points: 14%
(Cancer 2010)
Does the interval b/t development of motor deficits and RT predict response?
Yes, a longer time interval results in improved functional outcome. A retrospective review of 96 pts demonstrated improved function in 86% of pts when motor Sx were present >14 days. In contrast, only 10% improved when Sx were present <7 days. (Rades D et al., IJROBP 1999)
How are conventional RT fields arranged to treat the cervical, thoracic, and lumbar spine?
Field arrangement for cord compression:
Encompass the lesion + 1–2 vertebral levels above and below.
Cervical: opposed lats
Thoracic: AP/PA or PA alone, respecting cord tolerance
Lumbar: AP/PA
Are there data to support the use of hypofractionation for cord compression?
Marranzano et al. enrolled 300 pts with metastatic SC compression and short life expectancy (≤6 mos) randomized to short-course (8 Gy × 2 fx, 1 wk apart) or split-course (5 Gy × 3 fx, 4-day rest, and then 3 Gy × 5 fx). No significant difference was observed b/t the 2 schedules with median f/u of 33 mos (response, duration of response, survival or toxicity). (JCO 2005) A f/u trial randomized 327 pts to 8 Gy × 2 fx (1 wk apart) vs. 8 Gy × 1 fx without a difference in outcome. No myelopathy was registered with a median f/u of 31 mos. (Radiother Oncol 2009)
More recently, in the SCORE-2 trial, Rades et al. randomized 203 pts with poor to intermediate expected survival to 4 Gy × 5 fx vs. 3 Gy × 10 fx; 155 pts were evaluable at 1 mo. Motor function was stable or improved in 87.2% vs. 89.6% (NSS), and ambulation was 71.8% vs. 74.0% (NSS). Similarly, no significant difference in ambulation was seen at 3 or 6 mos. (JCO 2016)
In addition, Hoskin et al. recently presented SCORAD III at ASCO 2017 which randomized 688 pts with SC compression to 8 Gy × 1 vs. 4 Gy × 5; ambulatory status at 8 wks was 69.5% with single fx and 73% with 5 fx (NSS) and OS was similar at 12.4 wks vs. 13.7 wks. Final manuscript pending.
