Lomustine for treatment of mast cell tumors in cats: 38 cases (1999-2005).
OBJECTIVE
To determine clinical activity and toxic effects of lomustine when used to treat cats with mast cell tumors (MCTs).


METHODS
Retrospective case series.


METHODS
38 cats with measurable, histologically or cytologically confirmed MCTs treated with lomustine at a dosage > or = 50 mg/m(2).


METHODS
Medical records were reviewed to determine response to treatment and evidence of drug toxicoses. The Kaplan-Meier method was used to estimate remission duration.


RESULTS
26 cats had cutaneous MCTs, 7 had MCTs of the mesenteric lymph nodes, 2 had gastrointestinal tract MCTs, 2 had hepatic MCTs, and 1 had MCTs involving multiple organs. Targeted lomustine dosage was 50 mg/m(2) in 22 cats and 60 mg/m(2) in 16 cats. Median administered dosage of lomustine was 56 mg/m(2) (range, 48 to 65 mg/m(2)), and median number of doses administered was 2 (range, 1 to 12). Seven cats had a complete response and 12 had a partial response, for an overall response rate of 50%. Median response duration was 168 days (range, 25 to 727 days). The most common toxicoses were neutropenia and thrombocytopenia.


CONCLUSIONS
Results suggested that lomustine had activity against MCTs in cats and was well tolerated. Further, findings suggested that treatment with lomustine should be considered for cats with MCTs for which local treatment is not an option.
Rassnick
Kenneth M
KM
Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Williams
Laurel E
LE
Kristal
Orna
O
Al-Sarraf
Renée
R
Baez
Jennifer L
JL
Zwahlen
Courtney H
CH
Dank
Gillian
G
D000818:Animals; D018906:Antineoplastic Agents, Alkylating / Q000009:adverse effects / Q000627:therapeutic use*; D002371:Cat Diseases / Q000188:drug therapy* / Q000473:pathology; D002415:Cats; D005260:Female; D053208:Kaplan-Meier Estimate; D008130:Lomustine / Q000009:adverse effects / Q000627:therapeutic use*; D008223:Lymphoma / Q000188:drug therapy / Q000473:pathology / Q000662:veterinary*; D008297:Male; D012515:Mast-Cell Sarcoma / Q000188:drug therapy / Q000473:pathology / Q000662:veterinary*; D009364:Neoplasm Recurrence, Local / Q000662:veterinary; D009367:Neoplasm Staging / Q000662:veterinary; D011379:Prognosis; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000662:veterinary*; D016896:Treatment Outcome
D018906:Antineoplastic Agents, Alkylating; D008130:Lomustine