Prednisone as Single-Agent Therapy for Dogs with Lymphoma

Although lymphoma in dogs is highly responsive to the well-documented CHOP protocol (ie, cyclophosphamide, doxorubicin, vincristine, prednisone), many pet owners opt for therapeutic management with prednisone alone. Prednisone is commonly used as single-agent therapy for lymphoma in dogs, but no prior controlled studies have documented benefits of this treatment.

This study evaluated survival time in client-owned dogs (n = 109) with previously untreated peripheral nodal, cytologically confirmed, intermediate- or large-cell lymphoma treated with prednisone alone. Patients received 40 mg/m² PO every 24 hours for 7 days and were then maintained at 20 mg/m² PO every 24 hours; clinicians could increase or decrease the dose at their discretion. 

Owners completed a standardized quality-of-life (QOL) survey on the first day of therapy and at set intervals throughout treatment. Patients were also assessed based on substage at the time of study enrollment (substage a: no clinical signs; substage b: GI signs, respiratory signs, hypercalcemia, fever, hyphema, uveitis) and disease immunophenotype (B cell or T cell). 

Median survival time was 50 days. Although some patients survived >120 days, probability of 6-month survival was 7%. Increased survival time generally correlated with absence of clinical signs (ie, substage a) and high QOL in the first 14 days of the study.

Key pearls to put into practice:

Although prednisone alone does not provide extended survival time in dogs with lymphoma, it can improve QOL as disease progresses. Prednisone is inexpensive, is easy to administer, and has minimal adverse effects; however, survival times (median, 50 days) are short, and there are negative effects of starting cytotoxic chemotherapy after prednisone administration if the owner reconsiders treatment.

Median survival time was most positively correlated with lack of clinical signs at the time of study enrollment and high QOL when treatment was initiated, but not all patients had the same response. Variability in response to any treatment for dogs with lymphoma should be discussed with owners.

QOL scoring is valuable for patients with chronic, deteriorating conditions and can be used by clinicians and owners to guide treatment decisions or end-of-life care.