Distinct effects of anti-inflammatory and anti-thrombotic drugs on cancer characteristics at diagnosis.
BACKGROUND
A previous study showed that regular use of low-dose aspirin was associated with smaller tumour size and fewer metastases for colorectal and lung cancer. We aim to explain these distinct effects in terms of the anti-inflammatory and anti-thrombotic properties of aspirin.


METHODS
From the Swedish Cancer Register, we identified patients diagnosed with colorectal and lung cancers between 1st October 2006 and 31st December 2009; each cancer was assessed in terms of tumour size/extent (T), lymph-node (N) and metastatic (M) status. Linkage with the Swedish Prescribed Drug Register was performed to obtain information on the use of low-dose aspirin, anti-inflammatory and anti-thrombotic drugs prior to cancer diagnosis.


RESULTS
We identified 14,743 individuals with colorectal cancer and 5888 with lung cancer. For low-dose aspirin users we observed a statistically significant association with smaller tumour size and fewer metastases. For both cancers, the use of non-aspirin anti-inflammatory drugs was associated with smaller tumour size in all categories T2-T4 odds ratio (OR = 0.76, 95% confidence interval (CI) 0.63-0.92 for T2 versus T1 in colorectal cancer), but not with metastatic status (OR = 0.94, 95% CI 0.84-1.06 in colorectal cancer). In contrast, anti-thrombotic drug use was associated with fewer metastases, but not with tumour categories T2 and T3.


CONCLUSIONS
The results suggest that the use of anti-inflammatories is associated with tumour-growth inhibition at the primary site, while the use of anti-thrombotics is associated with restriction of cancer-cell metastasising capability. These have clinical implications on the potential use of these drugs for chemoprevention or chemotherapy.
Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden. Electronic address: yudi.pawitan@ki.se.
Yudi
Y
Pawitan
Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
Li
L
Yin
Department of Integrative Biology, University of California, Berkeley, United States.
Andrea
A
Setiawan
Department of Oncology and Pathology, Karolinska Institutet, Stockholm, Sweden.
Gert
G
Auer
Unit of Clinical Epidemiology, Department of Medicine, Karolinska Institutet, Stockholm, Sweden.
Karin E
KE
Smedby
Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
Kamila
K
Czene
D000368:Aged; D000369:Aged, 80 and over; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage*; D000925:Anticoagulants / Q000008:administration & dosage*; D001241:Aspirin / Q000008:administration & dosage*; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000473:pathology*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000453:epidemiology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D013548:Sweden / Q000453:epidemiology
D000893:Anti-Inflammatory Agents; D000925:Anticoagulants; D001241:Aspirin
Anti-platelet; COX inhibitors; Carcinogenesis; Chemoprevention; Chemotherapy; Drug prescription registry; Metastasis