摘要：

Background: Mucinous adenocarcinoma of the anal canal (MAAC) is a relatively rare disease, constituting less than 10% of anal cancers. It carries a relatively poor 5-year survival rate of between 50-60%. MAAC rarity and proximity to rectal mucosa can present a diagnostic challenge as it can be misidentified as adenocarcinoma of the lower rectum. Because of its rarity, the bulk of knowledge of the disease is derived from individual case studies or small institutional reviews. Thus, there remains no clear standard of treatment for AAC. While abdominal perineal resection is the main management approach, the role of systemic therapy and radiation on clinical outcomes remains ill-defined. The lack of national guidelines, variability in institutional approaches and in access to tertiary cancer centers may contribute to differences in patient outcomes and raise the question of healthcare disparities. In this study, we analyzed the data from 767 patients with MAAC from the National Cancer Database (NCDB). Methods: We obtained clinicopathological demographic, socioeconomic data and survival outcomes from 767 patients with MAAC that were registered in the NCDB from 2004 to 2017. The treatment patterns and prognostic factors were analyzed. Results: The majority of patients, 85%, were older than 50. White patients comprised 75.6%, Black 18.8% and Asians 3.3%. Only 3.9% were Hispanics. Among 647 patients who had survival data, the majority received the following therapies: 311 received surgery and chemoradiation, 131 only surgery and 131 only chemoradiation. White and Black patients had similar survival odds, whereas Asian patients had significantly higher overall survival (OS) (HR 0.42). Patients treated at academic facilities had significantly better OS than patients treated at non-academic facilities (HR 1.41-1.57), and patients with private insurance (HR 0.37) had significantly better survival when compared to patients with other insurance types. Patients with only Stage II exhibited significant survival differences when given both surgery and chemoradiation, compared being given either treatment modality alone (HR 0.56); interestingly, male patients in this group did not benefit from adding chemoradiation to surgery while female patients did (p = 0.1, p = 0.011). Conclusions: Surgical resection seems to be the most important treatment modality in MACC, while for patients with stage II addition of chemoradiation statistically significantly improves survival. Access to tertiary cancer centers and therapy costs contribute to differences in survival outcomes, which brings the question of healthcare disparities and the need for national guidelines for MACC management.

展开