Lymphoma in dogs: CHOP-based multi-agent chemotherapy vs single-agent doxorubicin — POSSIBLE (the treatment made no difference)

In dogs with treatment-naïve multicentric lymphoma, does a CHOP-based multi-agent protocol give longer remission and survival than single-agent doxorubicin?

Shelf #102 · gate-verified and approved by the developer

POSSIBLE (the treatment made no difference): The only direct comparison of a multi-agent protocol against single-agent doxorubicin (Simon 2008) was a nonrandomised controlled trial in 114 dogs, and it found no significant difference in remission or survival time between a continuous multiagent doxorubicin-based protocol and a short-term single-agent doxorubicin protocol. Complete remission was numerically more frequent with multiagent treatment (63 of 86, 73%, vs 14 of 27, 52%), but no remission-duration or survival advantage could be demonstrated, and vomiting was more common on the multiagent protocol. The supporting single-arm record (Higginbotham 2013) shows intermittent single-agent doxorubicin is genuinely active (78% complete response, median survival 169.5 days), while its own authors state it is not a substitute for multiagent protocols — a judgement resting on cross-study comparison, not on a randomised head-to-head. No randomised CHOP-vs-doxorubicin trial was found; that is the central gap, and non-random allocation in Simon means cases may have been channelled between protocols by severity or owner preference, biasing the comparison in an unknown direction. The neighbouring question of doxorubicin with vs without added cyclophosphamide is carded on shelf #101 and is not re-carded here. Tier C (survival benefit claim). Drafted Nov 10, 2026 (VetMed build, topic #102); all figures from abstracts fetched and verified at drafting.

Simon 2008: no significant difference in remission or survival between a continuous multiagent protocol and short-term single-agent doxorubicin in 114 dogs with lymphoma

Nonrandomized controlled clinical trial (record's own design wording; publication type: Controlled Clinical Trial)

Who: Dogs: 114 dogs with lymphoma treated in a German university referral setting (lead affiliation University of Veterinary Medicine Hannover). Multiagent arm n = 87: a continuous protocol of L-asparaginase, vincristine, cyclophosphamide, doxorubicin, methotrexate and prednisolone. Single-agent arm n = 27: doxorubicin alone on a short-term protocol. Allocation was not randomised.

Result: Complete remission in 63 of 86 (73%) multiagent dogs (response data unavailable for 1 dog) vs 14 of 27 (52%) single-agent dogs. No significant difference in remission or survival time could be demonstrated between treatment groups. Incidence of haematologic and gastrointestinal toxicoses did not differ between groups, except that vomiting was more common among dogs treated with the multiagent protocol. A high BUN concentration at the time of diagnosis was significantly associated with a lower likelihood of complete remission. The authors concluded that in this population no significant difference in remission or survival times could be identified between the two protocols.

Watch out: This is the only direct head-to-head comparison found, and it is explicitly nonrandomised: protocol choice may have tracked case severity, substage or owner finances, so the null is vulnerable to confounding in either direction. The record's abstract reports no median remission or survival figures, so none are quoted here. The multiagent protocol tested includes methotrexate and is not identical to every CHOP variant in clinical use.

Simon D et al. Efficacy of a continuous, multiagent chemotherapeutic protocol versus a short-term single-agent protocol in dogs with lymphoma. Journal of the American Veterinary Medical Association. 2008;232(6):879-85. PMID: 18341445. Registry ID: none in the record. MeSH: Animals · Antibiotics, Antineoplastic/therapeutic use · Antineoplastic Combined Chemotherapy Protocols/therapeutic use · Dog Diseases/drug therapy · Dog Diseases/mortality · Dogs · Doxorubicin/therapeutic use · Female · Lymphoma/drug therapy · Lymphoma/mortality · Lymphoma/veterinary · Male · Neoplasm Staging/veterinary · Remission Induction · Survival Analysis · Time Factors · Treatment Outcome

Higginbotham 2013: intermittent single-agent doxorubicin gave a 78% complete response rate and median survival of 169.5 days in 18 dogs with multicentric B-cell lymphoma

Single-arm clinical trial (publication types: Clinical Trial, Research Support, Non-U.S. Gov't; no comparator arm, and no randomisation or blinding stated in the record)

Who: Dogs: 18 dogs with B-cell lymphoma, all with multicentric disease, enrolled at referral teaching hospitals (Kansas State University and Oklahoma State University) for intermittent single-agent doxorubicin; median 4.5 doses administered. No concurrent control arm.

Result: Overall complete response rate 78%; median total doxorubicin remission time 80.5 days; median overall survival 169.5 days. First remission times were significantly affected by clinical stage and substage of disease. Outcomes were similar to those previously reported for single-agent doxorubicin treatment. The authors concluded that intermittent single-agent doxorubicin is not a substitute for multiagent chemotherapy protocols in canine lymphoma, but is a reasonable alternative if cost and time commitments are limiting factors for an owner.

Watch out: A single-arm series of 18 dogs: it benchmarks what single-agent doxorubicin alone achieves but cannot estimate the size of any multiagent advantage — comparing its survival figures with Simon's multiagent arm crosses studies, populations and eras. B-cell lymphoma only; T-cell disease is not represented.

Higginbotham ML et al. Intermittent single-agent doxorubicin for the treatment of canine B-cell lymphoma. Journal of the American Animal Hospital Association. 2013;49(6):357-62. PMID: 24051255. Registry ID: none in the record. MeSH: Animals · Antibiotics, Antineoplastic/administration & dosage · Dog Diseases/drug therapy · Dog Diseases/pathology · Dogs · Doxorubicin/administration & dosage · Drug Administration Schedule/veterinary · Lymphoma, B-Cell/drug therapy · Lymphoma, B-Cell/veterinary · Neoplasm Staging/veterinary · Remission Induction · Survival Analysis · Treatment Outcome

Synthesis: the only direct comparison is non-randomised and null on remission and survival; single-agent doxorubicin is active but unproven as an equal

Synthesis

Who: Synthesis of the cards above: Simon 2008 (114 dogs with lymphoma, nonrandomised controlled trial, continuous multiagent protocol n = 87 vs short-term single-agent doxorubicin n = 27) and Higginbotham 2013 (18 dogs with multicentric B-cell lymphoma, single-arm intermittent doxorubicin series).

Result: (1) Head-to-head, the multiagent protocol produced more complete remissions numerically (73% vs 52%) but no demonstrable difference in remission or survival time (Simon). (2) Single-agent doxorubicin alone is an active treatment, with a 78% complete response rate and median survival of 169.5 days in a small prospective series (Higginbotham). (3) The widespread belief that CHOP-based protocols outperform doxorubicin alone is not confirmed by the one direct comparison that exists — but that comparison was not randomised, so it cannot settle the question either.

Watch out: There is no randomised trial of CHOP-based multi-agent chemotherapy vs single-agent doxorubicin in dogs. Until one exists, protocol choice rests on the nonrandomised null, cross-study benchmarks, toxicity (more vomiting with multiagent treatment in Simon), cost and visit burden — not on demonstrated survival superiority in either direction.

Synthesis of Simon D et al. PMID: 18341445; Higginbotham ML et al. PMID: 24051255. Registry IDs as on the individual cards.

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