As more cats live into older age and owners pursue advanced diagnostics, understanding tumour patterns can help practices frame risk, prioritise investigations and support informed client conversations. A large retrospective analysis of more than 5,000 feline tumours provides updated data on tumour types, demographic associations and time trends.
The Study
Researchers analysed 5,289 primary tumours from 5,154 cats recorded in two Italian histopathology-based cancer registries between 2008 and 2023. Only histologically confirmed primary tumours were included; recurrences and metastases were excluded. Statistical analysis assessed associations between malignancy and age, sex, neuter status and breed grouping, as well as temporal trends.
Key results:
- 80.6% of tumours were classified as malignant
- The most common malignant tumours were:
- Fibrosarcoma (17.5%)
- Adenocarcinoma (15.4%)
- Squamous cell carcinoma (14.0%)
- Lymphoma (9.6%)
- Increasing age was associated with higher odds of malignancy overall (odds increased by around 8% per year of age).
- Females had higher odds of malignancy than males overall.
- Purebred cats had lower odds of malignancy compared with mixed-breed cats, although individual breeds were not analysed in detail.
- For adenocarcinoma (largely influenced by mammary tumours), neutered cats had lower odds than entire cats.
- The proportion of fibrosarcomas and adenocarcinomas decreased significantly over the study period.
- The proportion of squamous cell carcinomas increased significantly from 2008 to 2023.
- Lymphoma frequency remained stable over time and was relatively more common in younger cats compared with other tumour types.
Limitations
UK vets should interpret the findings in light of several constraints:
- Histopathology-only data: The study includes only masses that were biopsied or excised and submitted. Tumours diagnosed clinically or cytologically, or not sampled at all, are not represented. This may overestimate malignancy rates compared with the wider cat population.
- No population denominator: The study reports proportions and odds within submitted cases, not true incidence or population risk.
- Retrospective design: Clinical details were limited, including lack of information on timing of neutering, lifestyle factors (e.g. UV exposure) and comorbidities.
- Geographical context: Data were drawn from specific regions of Italy. Husbandry, vaccination practices, sun exposure and biopsy behaviour may differ from those in the UK.
- Breed analysis constraints: Low numbers in many pedigree categories meant breed-specific conclusions were limited.
Key takeaways for practice
- A high proportion of sampled feline tumours are malignant, reinforcing the value of early investigation and clear client communication around the benefits of histopathology.
- Increasing age remains a consistent risk factor for malignancy, supporting proactive work-ups of new masses in older cats.
- The observed rise in squamous cell carcinoma diagnoses highlights the need for vigilance with cutaneous and oral lesions, particularly in at-risk patients.
- The association between neutering and reduced odds of adenocarcinoma aligns with existing understanding of mammary tumour risk, although the study does not clarify timing effects.
- Consistent submission of samples for histopathology not only supports individual case management but contributes to the broader evidence base on feline cancer patterns.
Source: Scientific Reports, “Factors influencing malignant tumor development in cats from a multicenter retrospective study”, published January 2026.