McCutcheon, Ian E.

Background Pituitary carcinoma (PC) is an aggressive neuroendocrine tumor diagnosed when a pituitary adenoma (PA) becomes metastatic. PCs are typically resistant to therapy and develop multiple recurrences despite surgery, radiotherapy and chemotherapy. Recently, treatment with temozolomide (TMZ) has shown promising results, although the lack of prospective trials limits assessment of benefit. Methods We describe a single-center multidisciplinary experience in managing PC patients over a 22-year period and review previously published PC series. Results Seventeen patients were identified. Median age at PC diagnosis was 44 years (range 16–82 years), and the median time from PA to PC transformation was 5 years (range 1–29 years). Median follow-up time was 28 months. Most PCs were hormone-positive (n = 12): ACTH (n = 5), PRL (n = 4), LH/FSH (n = 2) and GH (n = 1). All patients underwent at least one resection and at least one course of radiation after PC diagnosis. Immunohistochemistry showed high Ki-67 labeling index (>3%) in 10/15 cases. Eight patients (47%) had only central nervous system (CNS) metastases; six (35%) had combined CNS and systemic metastases. The most commonly used chemotherapy was TMZ, and TMZ-based therapy was associated with the longest PFS in 12 (71%) cases, as well as the longest period from PC diagnosis to first progression (median 30 months). The 2, 3 and 5-year survival rate of the entire cohort was 71, 59 and 35%, respectively. All patients surviving >5 years had been treated with TMZ-based therapy. Conclusions PC management benefits from multidisciplinary care and multimodality therapy. TMZ-based regimens were associated with high survival rates and long disease control.

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.