No Increased Mortality Seen in axSpA Patients With Cancer

TORONTO — Older patients with axial spondyloarthritis (axSpA) are known to have a higher overall risk for cancer than the general population, but new evidence from a large population-based study indicated that when these patients have concurrent breast, lung, prostate, or colorectal cancer — the four most common cancer types — their rates of overall survival (OS) and cancer-specific survival (CSS) are similar to or better than those of patients with cancer alone.

Results from this new analysis of data from Medicare claims linked to the Surveillance, Epidemiology, and End Results database also showed that the rates of OS and CSS were significantly higher for patients with axSpA and concomitant colorectal cancer than for patients with colorectal cancer but not axSpA, even though past evidence suggested that for older patients with some other rheumatic diseases, there are worse cancer survival outcomes — for instance, patients with rheumatoid arthritis and concomitant breast or prostate cancer and those with systemic lupus erythematosus and breast cancer.

“We’re not entirely sure why survival rates were higher in colorectal cancer patients with axSpA, but it’s likely the use of [nonsteroidal anti-inflammatory drugs] NSAIDs in the treatment of axSpA played a role,” study presenter Savannah M. Bowman, MD, of Baylor College of Medicine in Houston told Medscape Medical News at the Spondyloarthritis Research and Treatment Network (SPARTAN) 2src25 Annual Meeting.

The hazard ratio (HR) for 5-year OS from colorectal cancer in patients with axSpA was src.72 (95% CI, src.62-src.83; P <.srcsrcsrc1), and the HR for 5-year CSS was src.73 (95% CI, src.55-src.97; P =.src3).

There were also no significant differences in OS and CSS in patients with axSpA and concomitant breast, prostate, or lung cancer compared with patients with cancer alone, with HRs of src.87, src.97, and src.94, respectively.

When asked to comment on the study findings, John D. Reveille, MD, professor of rheumatology at the University of Texas McGovern Medical School, Houston, said that the better survival rates seen in patients with axSpA may result from the close monitoring they receive because of their increased risk for inflammatory bowel disease.

“It’s likely these patients had colonoscopy [or other colorectal cancer screenings], and that this detected cancer earlier [than in patients without axSpA]. This would have resulted in better survival,” said Reveille, who was not involved in the study.

For the analysis, Bowman and study co-authors examined data from 61src3 patients, with and without axSpA, and a primary diagnosis of breast, prostate, colorectal, or lung cancer between 2srcsrc6 and 2src19. Of these patients, 2src61 had breast cancer, 1988 had prostate cancer, 1234 had lung cancer, and 82src had colorectal cancer. The mean age ranged from 74 to 77 years.

Patients in the axSpA cohorts were required to have two or more claims with a diagnosis of axSpA either 12 months before or after cancer diagnosis. They were matched to controls by gender, cancer type and stage, age at cancer diagnosis, and year of cancer diagnosis.

Patients with diagnostic claims for connective tissue diseases were excluded from the control cohorts.

Survival time was assessed using Kaplan-Meier analysis and log-rank tests. Cox proportional hazard regression models were performed for each type of cancer and adjusted for competing risks for CSS.

“Further research is needed to explore the potential reasons for longer survival in elderly patients with colorectal cancer and axSpA compared to those without axSpA,” the investigators concluded.

Reveille agreed. “The lack of previous research on colorectal cancer in axSpA patients suggests a need for further studies,” he told Medscape Medical News.

Bowman said she plans to use the IQVIA claims database to conduct the same analysis in younger patients. She would also like to analyze the impact of treatment with tumor necrosis factor inhibitors, interleukin 17 inhibitors, and Janus kinase inhibitors on cancer outcomes in patients with axSpA.

Reveille reported having a