Impact of chemotherapeutic dose intensity and hematologic toxicity on first remission duration in dogs with lymphoma treated with a chemoradiotherapy protocol.
BACKGROUND
Dose intensity has proven to be critical in maximizing chemotherapeutic efficacy for numerous human cancers. To date, the impact of dose intensity and toxicity on first remission duration has not been thoroughly assessed in dogs with lymphoma.


OBJECTIVE
Dogs that receive maximal dose intensity will have prolonged first remission duration.


METHODS
Sixty-two dogs with lymphoma that were treated according to a standardized chemoradiotherapy regimen and achieved durable complete remissions were identified from the medical records database of North Carolina State University.


METHODS
Dosage reductions and treatment delays resulting from chemotherapy-related neutropenia were evaluated retrospectively, and each patient's actual summation dose intensity and frequency of myelotoxicity were calculated. Impact of dose intensity and frequency of neutropenia on first remission duration were evaluated by Cox proportional hazards regression.


RESULTS
Development of grade III or IV neutropenia during chemotherapy was found to be associated with prolonged first remission duration (P < .01). Dose intensity did not have a significant impact on remission duration (P = .07).


CONCLUSIONS
Results of this study suggest that dosage reductions and treatment delays instituted to avoid repeated neutropenic episodes do not reduce first remission duration. Prolonged remission duration in patients that developed grade III or IV neutropenic episodes indicates the need for further optimization of dosing strategies for canine lymphoma patients undergoing chemotherapy.
Vaughan
Andrew
A
Veterinary Teaching Hospital, College of Veterinary Medicine, North Carolina State University, Department of Clinical Sciences, 4700 Hillsborough Street, Raleigh, NC 27606, USA.
Johnson
Jeffrey L
JL
Williams
Laurel E
LE
D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D003131:Combined Modality Therapy / Q000662:veterinary*; D004283:Dog Diseases / Q000188:drug therapy*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D017619:Hemibody Irradiation / Q000662:veterinary; D008223:Lymphoma / Q000188:drug therapy / Q000532:radiotherapy / Q000662:veterinary*; D008297:Male; D012074:Remission Induction