Colorectal high-grade neuroendocrine carcinoma: A single institution experience.

Abstract

540 Background: Colorectal high-grade neuroendocrine carcinoma (HGNEC) is a rare and aggressive disease that lacks standard management recommendations. Methods: The records of all patients with colorectal HGNEC diagnosed at MD Anderson Cancer Center between 1991 and 2013 were retrospectively reviewed for clinicopathological features and clinical outcomes. Results: One hundred patients with histologically confirmed colorectal HGNEC were identified. Median age at diagnosis was 55 years with 51 males. Family history of cancer was present in 59% (first degree) of patients and a tobacco smoking history in 54%. Most frequent symptoms at diagnosis were: abdominal or rectal pain (52%), rectal bleeding (49%) and change in bowel habit (52%). Small cell carcinoma was the most common histology (89%), with large cell neuroendocrine carcinoma in 8% and mixed histology 2%. The expression of chromogranin, synaptophysin and neuron specific enolase was positive in 58%, 93% and 87%, respectively. In our institution, 40% of HGNECs arise in the rectum, compared to 25% of adenocarcinomas (P<0.001 for comparison). Sixty four patients (64%) presented with metastatic disease at diagnosis. Median overall survival (OS) was 11.8 months, with 19.3 versus 8 months for localized and metastatic disease, respectively (p<0.01). Two and five year OS was 23% and 8%, respectively. Cecal primaries had a higher rates of metastatic disease at presentation (OR=5, P=0.026), but stage-specific outcomes did not differ by tumor location. Treatment with a platinum-based chemotherapy (CT) was used in 63 (81%) patients in first line palliative CT and the objective response rate was 43%. For localized disease, neoadjuvant treatment was used in 36% of patients and adjuvant therapy in 47% and was associated with a trend toward improved survival (median OS 20.4 versus 15.4 months, P=0.08). Conclusions: Colorectal HGNEC has an aggressive biology with rectum being the most common site and cecum the site most associated with distant metastases at diagnosis. For localized disease early diagnosis and multimodality approach are important for better outcomes while systemic CT appears to be the mainstay of treatment for advanced disease.