Environmental and Lifestyle Risk Factors for Oral Squamous Cell Carcinoma in Domestic Cats

Abstract

Oral squamous cell carcinoma (SCC) is a common malignancy in cats, but little currently is known about its etiology. We examined the relationship between risk of oral SCC and factors such as environmental tobacco smoke, flea control products, and diet in 36 domestic cats with histologically confirmed oral SCC and 112 renal disease control cats presented to a large veterinary referral hospital between 1994 and 2000. Questionnaires were mailed to owners of all study and control cats to assess demographic characteristics, lifestyle factors, and level of chemical exposures 2 years before diagnosis. Multivariate relative risks (RR) were used to estimate the relationships between the various factors and the risk of oral SCC. Flea control product use and diet were significantly associated with risk of oral SCC. Cats that wore a flea collar had 5 times the risk of oral SCC as nonusers, after adjustment for other factors (RR = 5.3; P = .002). In contrast, use of flea shampoo substantially reduced risk. Compared to cats eating mostly dry food, those with high canned food intake had a 3-fold increase in risk (RR = 3.6; P = .014); canned tuna fish intake was independently associated with risk (RR = 4.7; P = .004). Exposure to household environmental tobacco smoke was associated with a nonsignificant 2-fold increase in risk (P = .11). Results of this study suggest that flea control products, diet, and perhaps environmental tobacco smoke might be associated with risk of oral SCC and indicate that further investigation into these relationships is warranted.

Bone-Invasive Oral Squamous Cell Carcinoma in Cats

“…These findings are similar to what Bertone et al reported in 2003, when they compared patient signalment and history between 36 cats with OSCC and 112 cats with renal disease. 2 Similarly, no breed predisposition was detected in the study performed by Stebbins et al 30 Interestingly, our study demonstrated that there were more intact cats (regardless of sex) in the OSCC group than in the control group (21% compared to 15%). The reason why intact cats are overrepresented in the OSCC group is unknown, but it may involve either the influence of hormones such as estrogen and testosterone on the development and progression of OSCC or the role of other factors associated with neuter status, such as living indoors or outdoors, type of diet, and exposure to infectious agents and environmental carcinogens.…”

“…36 Most human cases occur in men older than 45 years who use tobacco and/or consume alcohol. 28 Whereas cats do not share the same risk factors as most human patients with OSCC (although some cats are exposed to environmental tobacco smoke in their homes), 2 they may have similarities to a small subgroup of human patients with OSCC who are unique in that they do not smoke or consume alcohol, they tend to be female, they have tumors of the oral cavity (as opposed to the oropharynx, a common site among people who smoke and consume alcohol), and they are older than patients who smoke and consume alcohol. Risk factors for the development of OSCC in this subgroup of human patients are unknown.…”

“…26 Bertone et al demonstrated a 2-fold increased risk for the development of OSCC in cats exposed to environmental tobacco smoke. 2 Perhaps the expression of polymorphic and site-specific xenobiotic metabolizing enzymes in the lingual mucosa makes some cats more susceptible to carcinogenesis, thereby developing OSCC of the tongue at an earlier age. Cats may be exposed to carcinogens in environmental tobacco smoke or other sources as they are deposited on the hair coat and introduced to the tongue through grooming.…”

Quantitative Expression and Co-Localization of Wnt Signalling Related Proteins in Feline Squamous Cell Carcinoma

“…The etiopathogenesis of feline SCC is unknown, but some factors have been implicated to increase the risk of development of this type of cancer. For example, cats living in households with smokers are considered more at risk of developing FOSCC compared to non-smoking households [3, 4]. Papilloma virus is considered another putative risk factor as in one study 90% of feline cutaneous SCC carried papillomavirus DNA [5].…”

Animal Models of Bone Metastasis

“…6,8,73,103,168 Environmental tobacco smoke (ETS) exposure, flea collar use, canned foods, and papillomavirus infection have been implicated as being potentially involved in SCC development in cats. 9,103,126,182 Adjacent bone invasion, lymph node metastasis, and spontaneous recurrence are frequent complications in this cancer. 126,127 At the time of diagnosis, the disease is often in the late stages with extensive bone invasion.…”