An Analysis Of Prognostic Factors Of Primitive Neuroectodermal Tumor After Surgery

Objective To evaluate the multimodal treatment outcomes and prognostic factors of primitive neuroectodermal tumor after surgery. Methods Forty-one patients who were diagnosed with primitive neuroectodermal tumor in PLA General Hospital from June 2008 to December 2014 were retrospectively analyzed. There were 24 males and 16 females. The median age was 24 years, ranging from 4 to 65 years. There were 6 patients with cPNET and 35 patients with pPNET. Original sites of 8 cases were located in the limbs, while 33 cases were located in the trunk(10 in the brain and headface,4 in the spinal canal and vertebral body side,5 in the chest,7 in the abdomen and 7 in the pelvic). All of the patients underwent surgical treatment. Two patients received surgery alone; Twenty-two patients received surgery and chemotherapy without radiotherapy; Four patients received surgery and radiotherapy without chemotherapy; Thirteen patients received surgery, radiotherapy and chemotherapy. Results The overall median survival time was 38 months. The overall survival (OS) rates of lyear,3 years and 5 years were 87.8%,51.9% and 37.1%. The progression-free survival (PFS) rates of lyear and 2 years were 41.3% and 29%. Twenty-six patients had relapse of the disease(63.4%). The univariate analysis showed that gross tumor resection and recurrence after surgery affected the survival of PNET patients after surgery. Radiotherapy could improve the prognosis of the patients. Incomplete tumor resection promoted tumor progression. The multivariate analysis concluded that gross tumor resection and surgery combined with chemoradiotherapy were independent prognosis factors(P=0.006 and P=0.013, respectively). Tirty patients had post-operativerecurrence. For these patients, the overall median survival time was 30 months and the overall survival (OS) rates of lyear,3 years and 5 years were 80%, 44.1%and 20.7%. Twenty-six patients (86.7%)had local recurrence, and 4 patients (13.3%) had distant recurrence. The overall median relapse-free survival time was 4 months. The relapse-free survival (RFI) rates of 6 months, lyear and 2 years were 33.3%,16.7%and 6.7%. The overall median postrecurrence survival time was 14 months. The postrecurrence survival (PRS) rates of lyear,3 years and 5 years were 60.7%,16.9%and 8.4%.The univariate analysis showed that radiotherapy and RFI>6 months predicted significantly better outcome (P=0.006 and P=0.001, respectively). Sex, age, radiotherapy and RFI>6 months have no prognostic significance for PRS(P=0.234, P=0.797, P=0.053 and P=0.141). The multivariate analysis concluded that radiotherapy and RFI>6 months were independent prognosis factors(P=0.047 and P=0.012, respectively). Conclusion Surgery combined with chemoradiotherapy is still the recommended multimodal treatment regimen for PNET patients. Recurrence after surgery affected the survival of PNET patients severely. Radical resection of tumor could improve the prognosis of PNET patients treated with surgery.The prognosis of primitive neuroectodermal tumor with recurrence after surgery is very poor. Radiotherapy has important significance to the prognosis of PNET patients. RFI< 6 months is associated significantly with OS of PNET patients who experience recurrence severely, rather than with PRS.