Pituitary carcinoma: The University of Texas MD Anderson Cancer Center experience.

Abstract

2068 Background: Pituitary carcinoma (PC) is a rare and aggressive neuroendocrine tumor diagnosed once a pituitary adenoma (PA) becomes metastatic. Although no standard treatment currently exists, surgery, radiation (XRT) and/or chemotherapy are most commonly used. Recently, treatment with temozolomide (TMZ) has shown promising results, although the lack of prospective trials limits accurate outcome assessment. Methods: We describe a single-center multidisciplinary team experience in managing PC patients over a 13-year period (Oct, 2003 to Jan, 2017). Results: A total of 17 patients (9 males) were seen. Median age at diagnosis of PC was 44 years (range 16-82 years) and the median time from PA to PC conversion was 6 years (range 1-29 years). Median follow-up time: 28 months (range 8-158 months) with 7 reported deaths. The majority of PC was hormone-secreting (HS) subtype (n = 12): ACTH (n = 5), PRL (n = 4), FSH/LH (n = 2), GH (n = 1). After PC diagnosis, all pituitary tumors were locally invasive, all underwent at least one resection (mean 2.3) and all received at least one course of XRT alone (IMRT = 76%, SRS = 29%, IMPT = 12%) or concurrent with chemotherapy (18%). Immunohistochemistry showed high Ki-67 labeling index ( > 3%) in 9 (53%) cases. Most cases (n = 14) had metastases to the CNS, 35% of those had combined CNS and systemic foci. Ten (59%) cases underwent focal treatment of metastases, 90% of which underwent XRT. The most common chemotherapy used was TMZ [n = 14 (82%): single agent (n = 10); TMZ+capecitabine (n = 5); concurrent TMZ+XRT (n = 3); concurrent TMZ+XRT with adjuvant TMZ (n = 1)]. The median longest progression-free survival (LPFS) was 18 months (range 4-45 months). TMZ was associated with the chemotherapy-related LPFS in 9 (75%) cases. The 2, 3 and 5 year survival rate was 65%, 53% and 35%, respectively. All patients surviving > 5 years were treated with TMZ (n = 5, 2 survived > 10 years). Two refractory cases are currently on PD-1 inhibitor agent. Eighty percent of non-functioning PC were alive at last follow-up (HS-PC, 58%). Recurrence occurred in 11 (65%) cases. Conclusions: Treatment of PC requires a multidisciplinary approach. Multimodality therapy with surgery, radiation and TMZ was associated with higher survival rates and longer PFS.