(HealthDay News) — Aspirin use after colon cancer diagnosis improves survival if tumors express human leukocyte antigen (HLA) class I antigen, according to a study published online March 31 in JAMA Internal Medicine.
Marlies S. Reimers, MD, from Leiden University Medical Center in the Netherlands, and colleagues modeled survival in a cohort study with tumor blocks from 999 patients with colon cancer, surgically resected between 2002 and 2008.
HLA class I antigen and prostaglandin endoperoxide synthase 2 (PTGS2) expression were analyzed, and mutation analysis of PIK3CA was conducted. A prescription database was used to obtain data on aspirin use after diagnosis.
The researchers found that the adjusted rate ratio for the overall survival benefit associated with aspirin use after colon cancer diagnosis was 0.53 (P < 0.001) when tumors expressed HLA class I antigen and 1.03 (P = 0.91) when HLA antigen was lost.
A similar benefit of aspirin was seen for tumors with strong and weak PTGS2 expression (rate ratios, 0.68 and 0.59, respectively) and for wild-type PIK3CA tumors (rate ratio, 0.55). There was no correlation noted for mutated PIK3CA tumors (rate ratio, 0.73; P = 0.44).
“Aspirin use after colon cancer diagnosis was associated with improved survival if tumors expressed HLA class I antigen,” the researchers wrote. “HLA class I antigen might serve as a predictive biomarker for adjuvant aspirin therapy in colon cancer.”
In an accompanying commentary, Alfred I. Neugut, MD, PhD, of Columbia University, New York, discussed what these findings may mean for clinical practice.
“For my own patients, I have so far not recommended aspirin [for colon cancer]. But I think based on current evidence, that if I personally had a stage III tumor, I would add aspirin to my FOLFOX (folinic acid-flourouracil-oxaliplatin) adjuvant therapy. And if I feel that way for myself, should I not convey that to my patients?” Neugut wrote.
“But for now, as far as I am concerned, when a patient or a patient’s spouse asks, “What else should he be doing, Doctor?” – I will have a ready response.”
Two authors disclosed financial ties to the pharmaceutical industry.
- Reimers MS, Bastiaannet E, Langley RE, et al. Expression of HLA Class I Antigen, Aspirin Use, and Survival After a Diagnosis of Colon Cancer. JAMA Intern Med. 2014; doi:10.1001/jamainternmed.2014.511.
- Neugut AI. Aspirin as Adjuvant Therapy for Stage III Colon Cancer: Standard of Care? JAMA Intern Med. 2014; doi:10.1001/jamainternmed.2013.14544.