Login to Access Video or Poster Abstract: MP37-16
Sources of Funding: none

Introduction

Malignant Pheochromocytoma (PHEO) may present with metastatic disease earlier or later. The metachronous and synchronous metastatic disease may have different behavior. Besides, disease prognosis is not constant over time; consequently, the conditional survival (CS) of patients with malignant PHEO needs to be evaluated.

Methods

The Surveillance, Epidemiology, and End Results (SEER) database was queried for patients aged >18 years diagnosed with malignant PHEO between 1988 and 2012. Demographic, clinical and pathologic informations were collected. Conditional survival, CS(y/x), is the probability of surviving an additional y years, given that the patient has already survived x years. The mathematical definition of CS can be expressed as: CS(y/x)=S(x+y)/S(x).

Results

A total of 277 patients were identified.In univariate analysis, factors associated with lower overall survival (OS) included older age, larger tumor size, diagnosed with distant metastases, failure to underg any surgery and necessitating radiotherapy. Cox proportional hazards regression analysis showed that factors independently associated with higher overall mortality were older age, diagnosed with distant metastases and failure to undergo any surgery. Patients diagnosed with metastatic disease had a poor prognosis with a median OS of 23 months, while patients diagnosed with nonmetastatic disease had a longer median OS of 116 months. Patients of younger age, with smaller size and who underwent surgery had significantly better OS, while the clinical stage at diagnosis did not affect survival in the metachronous metastatic subgroup. CS estimates were more encouraging than static survival probabilities. During the first 5 years after their initial diagnosis, the 1-year CS of patients who had survived >24 months increased to approximately 90%, while OS decreased progressively from about 80% to 60%. The gains in 1-year CS over time were more pronounced in patients with poor prognostic factors, including older age, diagnosed with distant metastases and failure to undergo any surgery. These differences in 1-year CS between the different prognostic factor groups decreased with time from diagnosis, or even disappeared.

Conclusions

These findings provided a new perspective for understanding the prognosis of malignant PHEO.

Funding

none