Central Nervous System

PV QA 2 - Poster Viewing Q&A 2

MO_6_2619 - Clinical Outcomes for Primary Parenchymal Tumor of Intermediate Differentiation

Monday, October 22
10:45 AM - 12:15 PM
Location: Innovation Hub, Exhibit Hall 3

Clinical Outcomes for Primary Parenchymal Tumor of Intermediate Differentiation
B. Khodayari, and W. W. Lien; Kaiser Permanente Los Angeles Medical Center, Los Angeles, CA

Purpose/Objective(s): Pineal parenchymal tumor of intermediate differentiation (PPTID) is a rare malignancy accounting for <1% of CNS tumors. Management remains controversial and a standard of care has not been well established. This analysis investigates the treatment outcomes for a single institution series of PPTID.

Materials/Methods: Twelve cases of non-metastatic PPTID were retrospectively identified from our institution’s pathology database between 1997-2016. Kaplan-Meier method with log-rank test was used for overall survival (OS), cancer-specific survival (CSS), and progression free survival (PFS) analyses.

Results: Median follow-up for patients still alive was 78 [16-234] months and for those deceased was 11 [2-44] months. The median age was 45 [15-64] years. Gross-total resection (GTR) was achieved in 42% of patients, sub-total resection (STR) in 42%, and 16% underwent biopsy only. Adjuvant cranio-spinal irradiation (CSI) was delivered to 42% of patients, adjuvant partial-brain radiation was delivered to 42% of patients, and 16% did not receive radiation therapy due to rapid disease progression. Adjuvant chemotherapy was given to 42% of patients. 33% of the cohort developed a recurrence, with local recurrence being the first site of failure in 75% of the patients. No patient with a GTR developed a recurrence. The 5-year OS, CSS, and PFS for the cohort was 62%, 74%, and 53%, respectively. Patients who achieved GTR versus no GTR were found to have a 5-year PFS benefit of 100% vs 29% (p=0.04) and a 5-year CSS of 100% vs 57% (p=0.13), respectively. There was no significant difference seen in CSI versus partial-brain radiation in 5-year PFS (80% vs 40%, p=0.39) or CSS (80% vs 100%, p=0.37). There was no benefit to the addition of chemotherapy versus no chemotherapy in 5-year PFS (60% vs 50%, p=0.64) or CSS (80% vs 100%, p=0.37).

Conclusion: PPTID patients who undergo aggressive local management with GTR and adjuvant radiation therapy achieve higher rates of PFS and CSS as compared to those who do not achieve GTR. Our series shows local progression as the primary recurrence pattern for these patients. Although the optimal adjuvant radiation volume has yet to be defined, there does not seem to be a significant PFS or CSS benefit with CSI over partial-brain field. The use of CSI should be utilized in carefully selected patients. With optimized care, there is a sub-group of PPTID patients who can achieve long-term disease control. Multi-center collaboration with a larger cohort size is needed to better evaluate this rare histology.

Author Disclosure: B. Khodayari: None. W.W. Lien: None.

Behnood Khodayari, MD, MS

Kaiser Permanente Los Angeles Medical Center

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