Patient and tumor characteristics
One hundred and one patients were included. Patient characteristics are detailed in Table 1. Women were older than men (median=45 vs 34 years, P=0.004). The lumbar localization was the most frequent (94%), more specifically the upper segments, as the L1, L2 or L3 vertebral levels were involved in 88% of patients. Thirteen patients (13%) presented multifocal MPE (2, 3 and 4 locations in 8, 3 and 2 patients respectively).
Pain was the main symptom: 90 patients (90%): 63 patients (62%) suffered from low back pain with radiculalgia, 19 patients (19%) isolated low back pain and 8 patients (8%) isolated radiculalgia. A nocturnal exacerbation was described in 20% of the cases.
The other symptoms such as sphincter, motor and sensory dysfunctions were almost equally distributed (41%, 35% and 37% of patients respectively). Among patients with sphincter dysfunction, 83% had chronic or acute urinary retention, 35% had urinary incontinence, 34% complained of abnormal anal sphincter function and 15% of erectile dysfunction.
Onset was abrupt in 12 patients and six of them showed intratumoral hemorrhage on MRI. Furthermore, one of these patients presented a sudden headache caused by subarachnoid hemorrhage with negative digital subtraction arteriography. MRI signals were not specific, the most frequent pattern was an iso signal T1 and a hypersignal T2. However, Gadolinium enhancement was constant. Diagnosis of MPE was preoperatively evoked for 61 patients (66%)
All patients underwent surgery. One patient (1%) underwent adjuvant radiotherapy. A GTR was achieved in 76 patients (75%). Near GTR was obtained in 8 patients (8%) and subtotal resection in 16 patients (16%). One (1%) patient had a partial resection. Dura matter was perforated by the tumor in 9 cases. GTR was obtained more frequently for solitary lesions compared to multifocal lesions (84% vs 15% P<0.001).
Six patients presented a postoperative cerebro-spinal fluid leakage (two required surgical treatment), four patients had an infection of the operative site (two required surgical treatment), five patients developed a meningocele (three required surgical treatment), three patients had arachnoiditis (one of them required surgical treatment), and one patient developed pneumocephalus. Other non-specific complications were reported: one pulmonary embolism, one pulmonary atelectasis and one ileus.
The median follow-up was 70 months [1 – 422]. No patient died during the follow-up. The evolutions of the main symptoms (motor dysfunction, sphincter dysfunction and pain) are summarized in Fig. 1. Most patients had functional improvement: 24/41 (59%) patients with sphincter dysfunction improved and 12/41 (29%) remained stable; motor function was improved in 24/35 (69%) patients and 7/35 (20%) were stable. Pain decreased or resolved in 76/90 (84%) patients.
Worsening of symptoms was recorded for 30 patients (30%) (Hypoesthesia n=14, motor function n=4, sphincter function n=12, pain n=3, deformation n=1). All motor declines occurred in patients presenting a preoperative motor deficit. Postoperative sphincter deterioration was present in 12 patients, including seven with normal preoperative sphincter function. Three patients needed permanent self-catheterization, and the others had perineal hypoesthesia or occasional urinary incontinence. Age, sex, overweight, tobacco use, large tumor sizes and time from first symptom to surgery were not associated with increased risk of functional decline (motor or sphincter). Preoperative deficits and significant tumor adherences seem to increase the risk of functional deterioration, although results did not reach statistical significance (P=0.07 and P=0.08 respectively).
Recurrence occurred in 16 patients (16%). One of them underwent initial adjuvant radiotherapy. Data are summarized in Table 2. The median time to recurrence was 25 months. Two recurrences occurred for initially undiagnosed bifocal lesions. Thirteen patients (13%) presented a local recurrence and 3 patients (3 %) a distant location. For five patients, recurrence was multinodular. PFS at 5 and 10 years were estimated at 83% and 79% respectively (Fig. 2).
Factors associated with tumor recurrence
In univariable analysis, preoperative factors significantly associated with recurrence were: involvement of at least one sacral level (OR=15.7 IC95%=[4.4-60.5], P<0.001), large tumors (OR=6.3, IC95%=[1.56-27.5], P=0.005) and multifocal lesions (OR=4.3, IC95%=[1.17-15.6], P=0.03). The intraoperative data that was significantly associated with recurrence were: subtotal resection (OR= 25 IC95%=[ 6.4-117], P<0.001), dural perforation by the tumor (OR=8.9 IC95%=[1.6-52], P=0.005), transfusion or bleeding >500cc (OR=8.6 IC95%=[1.75-58.2], P=0.002), surgery ≥3hours (OR=8.6 IC95%=[1.2-189], P=0.03) and substantial adherence (OR=3.7 IC95%=[1.1-13.7], P=0.045) (Fig. 3 and Table 3). The recurrence rate was 4% (3/76 patients) in the GTR group versus 52% (13/25 patients) in the STR group.
The multivariable model (Table 3) retained incomplete resection (OR=11.2 IC95%=[2.1-60.6], P=0.005) and the involvement of at least one sacral level (OR=7.7 IC95%[1.8-32.7], p=0.005) as being independently associated with tumor recurrence.
Management of recurrence
Among 16 recurrences (16%), 8 (50%) were treated with a second surgery, 2 (12.5%) with radiation therapy, 1 (6%) by surgery associated with radiotherapy, 1 (6%) with chemotherapy (temozolomide), and 2 (12.5%) followed by close monitoring. Two patients refused treatment, and both deteriorated to complete paraplegia. Four patients (25%) treated with surgery developed a new recurrence requiring additional treatment (radiotherapy and/or surgery). Tumors were controlled at last follow-up in 12/16 patients (75%) (Table 2).