Update From the Veterinary Cancer Society Annual Conference
ACVIM 2008
David Ruslander, DVM, DACVIM (Oncology), DACVR (Radiation Oncology)
Cary, NC, USA

Introduction

The 27th Annual Conference of the Veterinary Cancer Society was held in Fort Lauderdale, Florida November 1-4, 2007. Over 100 scientific abstracts were presented in both oral and poster format. This update is intended to give the breadth of the topics discussed, rather than the depth. Attendance and participation in the Veterinary Cancer Society is encouraged. Please try to attend the 2008 meeting in Seattle, Washington October 18-21, 2008. Complete proceedings and membership applications are available at http://www.vetcancersociety.org.

Canine Lymphoma

Rebhun et al. presented results of a study looking at prognostic significance of surviving expression in canine lymphoma, which indicated expression in B cell lymphomas predicted a more aggressive course but not necessarily survival. Lawman et al. presented some early clinical data of an autologous cancer vaccine, ImmunoFX for canine LSA, showing responses in all 7 dogs with dramatic regression in an indolent form of cutaneous LSA. Northrup presented information on 40 dogs with resistant LSA treated a MOPP protocol without the Vincristine. Median progression free and survival times were 55 and 23 days respectively following a median of 121 days from initial diagnosis. Clifford et al. presented a 10 week CHOP/CCNU protocol for relapsed lymphoma with a 93% CR/PR and median remission time of 158 days (CR 189 days PR 69 days) Prognostic factors included duration of first remission and response to therapy. Lurie et al. presented a retrospective study of Boxers with LSA which showed that 85% had T cell phenotype and these dogs had much shorter survival times (166 days) vs. the minority that had B cell (670 days.)

Feline Lymphoma

Krick et al presented data showing weight loss in cats underlying chemotherapy for LSA survived longer if they gained weight vs. lost weight or failed to gain weight

Canine Osteosarcoma

McNeil et al. presented an adjuvant doxorubicin/cisplatin or carboplatin for canine OSA. Median survival time was 264 days similar to other protocols. McMahon et al presented data indicating that gemcitabine was effective at inhibiting cell growth in 4/5 OSA cell lines. Petty et al. also showed variable but consistent anti-tumor effects of 2-deoxyglucose in OSA cell lines. Kosoya presented similar results using dihydroartemisinin an antimalarial drug that he showed had anti-OSA activity. This presentation was awarded the E. Gregory MacEwan award for outstanding basic science presentation for a resident. Henry et al. Presented data on toxicity and efficacy of combining Samarium 153 and carboplatin for canine OSA. While neutrophil counts dropped significantly lower in the combined arm of the study, morbidity was low, however the combination did not appear to improve local control or survival times. Dernell et al. reported on a combination of high dose radiation therapy +/- L-MTPE an immunomodulator for local OSA control. No difference in tumor necrosis was seen although toxicity was minimal. Garret et al. reported on 45 dog with mandibular osteosarcoma and showed a 627 day median survival with 35% 1 year and 16% 2 year survival. 58% developed metastasis. Smith et al. showed early results of cytolytic adenovirus therapy for dogs with OSA. Preliminary results indicate the therapy is well tolerated although efficacy was not the primary endpoint of the study. Marin et al. presented a study of hemostatic complications of greyhounds following amputations. This group of patients had a 36% incidence of bleeding associated with rhabdomyolysis with the recommendation of prophylactic administration of blood products prior to amputation in greyhounds.

Canine Mast Cell Tumor

Newman et al. reported on cytoxan/vinblastine/prednisone or Lomustine for metastatic mast cell tumors in dogs. 25% CR and 25% PR was seen in the Lomustine group but this response was a short median duration of 49 days. The CVP group had 32 % CR and 34% PR but median duration was also short-44 days. Rau et al. presented a multi-institutional study evaluating the treatment of bulky disease with radiation +/- chemotherapy in 65 dogs.3 dogs had a CR while 19 dogs had a PR but overall median survival time was only 98 days. Dogs with mucosal MCT and dogs whose chemotherapy was continued post radiation therapy had longer survival times. Hume et al. presented 49 dogs with Grade III MCT. Overall median survival time was 242 days. Local control stage, involvement of nodes, size of nodes and treatment of nodes were all of prognostic significance. London et al. demonstrated efficacy of a novel compound STA-9090, an HSP inhibitor against MST cell lines in both wild type and mutant kit cells. Dr Hahn presented results of a multi-center randomized placebo controlled study of a tyrosine kinase inhibitor AB1010 for MCT. Results were encouraging and little toxicity was noted.

Radiation Therapy

Gauthier presented 42 dogs receiving hypofractionated radiation therapy for anal sac adenocarcinoma +/- radiation therapy +/- chemotherapy. Median survival time was 343 days with 16% 2 year survival. Positive prognostic factors included female dogs, negative nodes, resolution of clinical signs and a PR or CR in the primary site or nodal site. Brugman et al presented 27 cases of non-adenocarcinoma nasal tumors in dogs treated with radiation therapy. Overall median survival time was 172 days

Canine Hemangiosarcoma

Dervisis et al. reported results of a doxorubicin/DTIC/cytoxan protocol for 20 dogs with metastatic HAS resulting in a MST of 120 days although 5/15 had a CR. Berger et al. presented a study of stage I/II vs. III hemangiosarcoma treated with the VAC protocol. Toxicity was well tolerated. Survival times were similar: 210 days vs. 195 days. Helfand presented in vitro data demonstrating inhibition of growth of HAS cells to the tyrosine kinase inhibitor Imatinib (Gleevac.) Chun et al. reported on the use of cardiac troponin I to identify cardiac involvement for dogs with suspected cardiac HSA. cTnI was more consistently elevated in this subset of patients but it did not identify 100% of affected patients.

Canine Sarcoma

Elmslie et al. presented results of 27 dogs with incompletely excised STS treated with a "metronomic" protocol of oral cyclophosphamide and piroxicam. This protocol significantly prolonged disease free interval in the treated population compared to the control arm. Cavanaugh et al presented data on dogs with incompletely resected distal extremity soft tissue sarcomas indicating that only 3/26 dogs succumbed to disease although local recurrence was 37% and was managed with repeat surgery.

New Drug Development

Vail et al. presented a safety/efficacy study of GS-9219 an antiproliferative nucleotide pro-drug. 38 dogs were treated and 79% response rate (CR and PR) was seen. Overall median duration of response was 129 days, slightly longer in previously untreated dogs. T cell tumors had a much shorter remission duration. Von Euler et al. presented data on Paclitaxel, a new formulation of Taxol. Neutropenia was noted but hypersensitivity was minimal and efficacy good with 67% response rate, 92% with MCT and SCC. Sahora et al presented a multi-institutional study investigating antiangiogenic thombosponding-1 peptides (ABT-510, ABT-898 bolus and ABT-898 depot) for dogs with soft tissue sarcomas. Approximately 25% had partial reduction in the size of the tumor although no complete responses were seen.

Canine Transitional Cell Carcinoma

Childress et al. presented a study evaluation cystoscopy vs. surgery for diagnosis of bladder tumors in 37 male dogs and 47 female dogs. As expected cystoscopy was more successful in obtaining the correct diagnosis in female dogs (95.5%) than in male dogs (60%) Abbo et al presented a phase I trial of intravesical Mitomycin C in dogs with TCC. The drug was well tolerated and pharmacokinetics were favorable for its use in TCC. Rankin et al demonstrated surviving expression in TCC and cystitis cases but differentiation between the two was not possible. Wheeler et al. demonstrated via PCR that TCC cells were positive for telomerase activity in contrast to normal cells. Arnold et al. presented data on the frequency and sites of metastasis for canine TCC indicating a 60% metastatic rate with 52% of all metastasis to the lung and 33% to the regional lymph nodes. Knapp et al presented a Phase III study of cisplatin compared to Firocoxib (Previcox) vs. Firocoxib (Previcox) cisplatin and Firocoxib. The combination of drugs had a significantly higher response rate (50% vs. <20%).Survival times did not appear to be significant. Firocoxib alone had anti-tumor activity.

Miscellaneous

Hammond presented data on cats with SCC treated with Strontium-90 which showed hat treatment with a single fraction may be as effective as multiple fractions. 88% had a CR and median survival time was 3076 days. Martinez-Ruzafa presented a gemcitabine/carboplatin protocol for feline carcinomas. Due to high rate of bone marrow suppression, the protocol was modified and the carboplatin was given 4 hours after the gemcitabine which improved toxicity rates. While this study was primarily a safety study, 1 cat with pancreatic carcinoma had a complete response. Villamil et al. utilized the Veterinary Medical Database to better define the epidemiology of canine skin tumors and found MCT in a higher than expected percentage of Boxers ( big surprise) Rhodesian Ridgebacks, Viszlas, Pugs and Boston Terriers. Siberian Huskies also appeared to be at increased risk for development of hemangiopericytomas. Deitz et al. presented Immunohistochemistry of 15 dogs with thyroid carcinoma showing COX-2 expression in all tumor samples and only sporadic expression in normal thyroid tissues. Rassnick et al. presented interesting data on the synergistic effects for calcitriol and cisplatin in vitro. This combination was safely given to tumor bearing dogs although hypersensitivity reactions and hypercalcemia was noted

References

1.  Proceedings of the 27th Annual Conference of the Veterinary Cancer Society, Fort Lauderdale, FLA

Speaker Information
(click the speaker's name to view other papers and abstracts submitted by this speaker)

David Ruslander, DVM, DACVIM (Oncology), DACVR (Radiation Oncology)
Vet Specialty Hospital of the Carolinas
Cary, NC


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