Background: The arrival of novel surgical techniques and chemotherapeutic agents has changed the range of available treatments and improved outcomes for stage IV rectal cancers. This is the largest study on stage IV rectal cancer to evaluate the change in treatment strategy and corresponding mortality from 1998 to 2009.
Methods: A population-based study was conducted using the National Cancer Database (1998-2009), which contains 70% of all cancer diagnoses in the U.S. After exclusion criteria were met, 25,046 stage IV rectal cancer patients were analyzed. Treatment modalities were compared by year of diagnosis between 1998 and 2009. Life tables were used to determine mortality by year. All statistics were run on SPSS Version 22 (IBM, Armonk, NY).
Results: Overall survival in stage IV rectal cancer has increased from 1998 to 2009 for 1-year survival (50% vs 61%) and 5-year survival (7% vs 12%). Analysis by treatment revealed that chemotherapy with radiation was most prevalent (20.6%) in 1998, but chemotherapy alone became the predominant treatment (25%) in 2009. Surgery as a planned first course of treatment decreased from 51.5% in 1998 to 27.2% in 2009, with a concordant increase in chemotherapy from 8.4% to 25% in that time frame. The largest 5-year survival increase across these years included surgery only (6% to 15%), surgery and chemotherapy (8% to 23%), and trimodal therapy (15% to 27%).
Conclusions: The outcomes for stage IV rectal cancer have meaningfully improved from 1998 to 2009, as evidenced by the significant improvement in 1- and 5-year survival. There has been a general trend to treat with chemotherapy and avoid surgery as a planned first course of treatment, despite improvement in mortality for both. Survival rates remain highest with trimodal therapy, but 5-year survival for surgery with chemotherapy and surgery only has also significantly improved from 1998 to 2009. Prior to the AVAHO annual meeting, we will conduct a multivariate analysis to evaluate other influences on survival such as age, comorbidities, insurance, education, and income.
