Mass Cell Tumors on Dogs and Cats
"Our animals shepherd us through certain eras of ourlives. When we are ready to turn the corner and make it on our own...they let us go." Anonymous
Us animal nutritionals of vermont
Mast Cell Tumors in dogs and cats
A mast cell tumor in a catis usually benign and found later in life whereas in a dog, the mast cell is malignant, a mass of cancerous mast cells.Mast cells are normally found in the tissues of the body and release histamine when stimulated by allergens.Histamine increases stomach acid production and causes symptoms such as runny noses and hives. Proteolytic enzymes are released by mast cells and delay healing of incisions.
The most common location of mast cell tumor is the skin but they can also be found in the liver,spleen, gastrointentinal tract, and blood stream.
For mast cell tumors, there is better prognosis for cats than there is for dogs.Mast cell tumors are common in dogs. Mast cell tumors are hard to distinguish between the more benign and the aggressive tumors. Secondary repurcussions such as internal bleeding, gastric ulcers and allergic reactions. Mast cells release chemicals that can cause havoc on the body.
Mast cell is also hard to diagnosis and one needs a biopsy and pathology report.
For cats, gastrointentinal tract is guarded but prognosis good for the other mass tumors.
for dogs:" Dogs
Prognosis of mast cell tumors of the skin is directly related to the grade of the tumor as determined by the biopsy results (histopathology) If the tumor has been completely removed with surgery, then recurrence of the tumor should be low
Grade 1 benign behavior excellent cure rate with surgery
Grade 2 moderately malignant behavior recurrence rate is about 20 % with aggressive surgery
Grade 3 very malignant tumor only 10% of these patients are alive at 1 year most of these have spread of tumor
Dogs living greater than 30 weeks after surgery and not having any recurrence of local or distant tumor are considered cured Prognosis of tumors of the internal organs is poor"

Lomustine for the treatment of gastrointestinal mast cell tumour in a dog.
1: J Small Anim Pract. 2006 Aug;47(8):465-7
Baldi A, Colloca E, Spugnini EP.
S A F U Department, Regina Elena Cancer Institute, Via delle Messi d'Oro 156, 00158 Rome, Italy.

An eight-year-old, male boxer dog was referred for the treatment of a large (5.5 x 5 cm), unresectable visceral mast cell tumour. The dog had a surgical resection performed one month before referral, and it had widespread metastases to the abdominal lymph nodes. The patient was treated with lomustine and prednisone and showed a rapid improvement and increased level of activity, weight gain and consistent tumour reduction. The patient remained in partial remission (defined as a greater than 50 per cent reduction in tumour volume) for seven months. Toxicity was acceptable and was limited to moderate anaemia and two episodes of neutropenia. At the completion of the seven months of therapy, the dog experienced a chemotherapy-induced sepsis, and the owners elected for euthanasia due to financial concerns. At that time, the tumour was still in partial remission. This case report suggests that a combination of lomustine and prednisone is an effective protocol for the palliation of aggressive visceral mast cell tumours.

Recurrence rate, clinical outcome, and cellular proliferation indices as prognostic indicators after incomplete surgical excision of cutaneous grade II mast cell tumors: 28 dogs (1994-2002).
: J Vet Intern Med. 2006 Jul-Aug;20(4):933-40.

Seguin B, Besancon MF, McCallan JL, Dewe LL, Tenwolde MC, Wong EK, Kent MS. Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, USA.

The objectives of this study were to determine local recurrence rate, clinical outcome, and prognostic value of the number of argyrophylic nucleolar organizer regions (AgNORs), presence of proliferating cell nuclear antigen (PCNA), and number of Ki-67-positive nuclei after incomplete surgical excision of canine cutaneous grade II mast cell tumors (MCTs). This retrospective study included 30 MCTs in 28 dogs. Medical records were examined and follow-up information was obtained from owners and referring veterinarians. Only cases in which excision was incomplete and no anvcillary therapy (other than prednisone) for MCT was given were included. Paraffin-embedded tumor tissues were retrieved for AgNORs, PCNA, and Ki-67 staining. Median follow-up time was 811.5 days. Seven (23.3%) tumors recurred locally. Median time to local recurrence was not reached with a mean of 1,713 days. The estimated proportions of tumors that recurred locally at 1, 2, and 5 years were 17.3, 22.1, and 33.3%, respectively. Eleven (39.3%) dogs developed MCTs at other cutaneous locations. Median progression-free survival was 1,044 days. Median overall survival was 1,426 days. The combination of Ki-67 and PCNA scores was prognostic for local recurrence (P = .03) and development of local recurrence was prognostic for decreased overall survival (P = .04). Results suggest that a minority of incompletely excised MCTs recur. Therefore, ancillary local therapies may not always be necessary. However, local recurrence can negatively affect survival of the affected dogs. Cellular proliferation indices may indicate the likelihood of MCT recurrence after incomplete excision.

Outcome and prognostic factors following adjuvant prednisone/vinblastine chemotherapy for high-risk canine mast cell tumour: 61 cases.
1: J Vet Med Sci. 2006 Jun;68(6):581-7

Thamm DH, Turek MM, Vail DM. Department of Clinical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison 53704, USA. The medical records of 61 dogs with MCT at high risk for metastasis that were treated with prednisone and VBL following excision+/-radiation therapy were reviewed, and median disease-free interval (DFI), median overall survival time (OS) and prognostic factors assessed. Adverse effects, mostly mild, were noted in 26% of patients, usually after the first VBL dose. 6.5% experienced severe neutropenia. The DFI was 1305 days, and the OS was not reached, with 65% alive at 3 years. 100% of dogs with "high-risk" grade II MCT were alive at 3 years. The OS for dogs with grade III MCT was 1374 days. Histologic grade, location (mucous membrane vs. skin) and use of prophylactic nodal irradiation predicted outcome. Prednisone and VBL chemotherapy is well tolerated, and results in good outcomes following surgery in dogs with MCT at high risk for metastasis. High-grade and mucocutaneous tumors had a worse outcome, and the use of prophylactic nodal irradiation appeared to improve outcome in this group of dogs.

Mast cells and angiogenesis in canine melanomas: malignancy and clinicopathological factors.
1: Vet Dermatol. 2006 Apr;17(2):141-6

Mukaratirwa S, Chikafa L, Dliwayo R, Moyo N. Department of Paraclinical Studies, Pathology Section, Faculty of Veterinary Science, University of Zimbabwe, PO Box MP 167, Mount Pleasant, Harare, Zimbabwe. The biological significance of mast cells and angiogenesis in canine melanomas is unclear. Eighty canine melanomas (56 malignant and 24 benign), investigated to determine the relationship between mast cell count (MCC), microvessel density (MVD) and clinicopathology, revealed significantly higher MCC and MVD counts in malignant melanomas. Evaluation of the prognostic significance of MCC and MVD in malignant melanomas showed a significant correlation between MCC and MVD both within and at the edges of the tumour. Multivariate analysis indicated that MCC and MVD were independent predictors of survival but the former was a significantly better prognostic marker. Greater numbers of mast cells and microvessels were found in malignant melanomas of poor prognosis. The findings demonstrate a prognostic significance of MCC and MVD in canine melanocytic tumours.

Effects of stage and number of tumours on prognosis of dogs with cutaneous mast cell tumours.

1: Vet Rec. 2006 Mar 4;158(9):287-91

Murphy S, Sparkes AH, Blunden AS, Brearley MJ, Smith KC. Centre for Small Animal Studies, Animal Health Trust, Lanwades Park, Kentford, Suffolk. Between 1997 and 1999, 280 dogs with mast cell tumours were identified, of which 59 (21 per cent) had multiple tumours. Follow-up data for survival analysis were available for 145 dogs with single tumours and 50 dogs with multiple tumours. There was no significant difference between the survival times of the two groups; the survival rates after 12 and 24 months were 88 per cent and 83 per cent, respectively, for the dogs with single tumours, and 86 per cent at both intervals for the dogs with multiple tumours. Eight of the dogs with single tumours had lymph node metastases (stage II disease) and these dogs had a median survival time of 431 days, whereas the 50 dogs with multiple tumours (classified as stage III disease) and the dogs with single tumours (classified as stage I disease) had not reached their median survival times. Golden retrievers appeared to be predisposed to developing multiple tumours in the population studied, with an odds ratio of 3.8. This study found no evidence that dogs with multiple tumours had different survival times than those with single tumours, although there was evidence that the presence of lymph node metastasis generally carried a poorer prognosis.

J Am Vet Med Assoc. 2004 Jan 1;224(1):79-82. :s Efficacy of radiation therapy for incompletely resected grade-III mast cell tumors in dogs: 31 cases (1987-1998).
Hahn KA, King GK, Carreras JK.
Banner 10000032
Gulf Coast Veterinary Oncologists 1111 W Loop South, Ste 150, Houston, TX 77027, USA.
OBJECTIVE: To determine the efficacy (durations of remission and survival) of an alternating-day radiation protocol for incompletely excised histologic grade-III solitary mast cell tumors (MCTs) in dogs. DESIGN: Retrospective study. ANIMALS: 31 dogs. PROCEDURE: Radiation (52 Gy in an 18-fraction alternating-day protocol) was delivered to an area bordered by margins > or = 3 cm around the surgical scar and to the associated local-regional lymph nodes. Dogs were not given chemotherapeutic agents concurrently or after radiation. Information on signalment, duration of remission, and survival time was obtained from medical records. RESULTS: Median and mean durations of remission were 27.7 and 17.0 months, respectively (range, 1 to 47 months). Median and mean durations of survival were 28 and 20 months, respectively (range, 3 to 52 months). Dogs with tumors located on the skin of the pinna, perineum, and prepuce had a median duration of remission greater than dogs with tumors located at other sites (27.7 and 14.4 months, respectively). Dogs with tumors < or = 3 cm in maximum diameter before surgery survived longer than dogs with tumors > 3 cm (31 and 24 months, respectively). The remission rate was 65% and survival rate was 71% at 1 year after treatment. Sixteen dogs that were euthanatized had complications associated with local-regional tumor progression. Systemic metastases to liver, spleen, intestine, and bone marrow were detected in 1 dog. CONCLUSIONS AND CLINICAL RELEVANCE: Without further treatment, incompletely excised grade-III mast cell tumors have high local-regional recurrence; local-regional treatment with radiation may effectively be used to manage many such tumors.
Mast Cell Tumors: Hot New Diagnostics and Treatment!
Gregory K. Ogilvie, DVM, Diplomate ACVIM (Internal Medicine, Oncology)
Professor and Head of Medical Oncology, Animal Cancer Center, Colorado State University Ft. Collins, CO, USA

"Mast cell tumors tend to metastasize to nodes, liver spleen and bone marrow...rarely to lungs.
Radiation therapy is extremely effective for controlling local disease.
Prednisone and vincristine when used as single agents induce a remission (partial or complete) in about 23% of the tumors"
J Am Vet Med Assoc. 2004 Jan 15;224(2):236-40. : Evaluation of surgical margins required for complete excision of cutaneous mast cell tumors in dogs.
Simpson AM, Ludwig LL, Newman SJ, Bergman PJ, Hottinger HA, Patnaik AK.
Department of Surgery, Donaldson-Atwood Cancer Clinic & Flaherty Comparative Oncology Laboratory, The Animal Medical Center, 510 E 62nd St, New York, NY 10021, USA.
OBJECTIVE: To determine whether neoplastic mast cells extended into tissue 1, 2, or 3 cm laterally or deeper than 1 fascial plane from the visible edge of cutaneous mast cell tumors (MCTs) in dogs. DESIGN: Prospective study. ANIMALS: 21 client-owned dogs with > or = 1 cutaneous MCT PROCEDURES: After preparation for surgery, each dog's skin was marked 1, 2, and 3 cm from the tumor edge at 0 degrees, 90 degrees, 180 degrees, and 270 degrees. At each 3-cm mark, deep fascia was exposed and sutured to the skin; the tumor was excised in routine fashion and fixed in formalin. Tumors were graded; margins were examined histologically for neoplastic mast cells. RESULTS: 23 cutaneous MCTs in 21 dogs were included in this study. Fifteen (65%) tumors were located on the trunk, 5 (22%) on the hind limbs, and 3 (13%) on the head and neck. There were 3 (13%) grade-I and 20 (87%) grade-II tumors. All grade-I tumors were completely excised at all margins. Seventy-five percent of the grade-II tumors were completely excised at the 1-cm margin, and 100% were completely excised at the 2-cm margin. Two grade-II MCTs located on the hind limbs of dogs were excised with a complete but close (within 1 mm) deep margin. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that a 2-cm lateral margin and a deep margin of 1 fascial plane appear to be adequate for complete excision of grade-I and -II MCTs in dogs.
  • J Vet Intern Med. 2003 Sep-Oct;17(5):687-92. : Biologic behavior and prognostic factors for mast cell tumors of the canine muzzle: 24 cases (1990-2001).
    Gieger TL, Theon AP, Werner JA, McEntee MC, Rassnick KM, DeCock HE.
    Veterinary Medical Teaching Hospital, University of California, School of Veterinary Medicine, Davis, CA, USA.

    The medical records of 24 dogs with histologically confirmed mast cell tumors (MCT) of the muzzle were retrospectively evaluated to determine their biologic behavior and prognostic factors. Information on signalment, tumor grade and stage, treatment methods, and pattern of and time to failure and death was obtained from the medical record. Twenty-three dogs were treated with combinations of radiotherapy, surgery, and chemotherapy; 1 dog received no treatment. There were 2 Grade 1, 15 Grade 11, and 7 Grade III tumors. Tumors were stage 0 (n = 8), stage 1 (5), stage 2 (6), stage 3 (4), and stage 4 (1). Mean and median survival times of treated dogs were 36 and 30 months, respectively. Prognostic factors affecting survival time included tumor grade and presence of metastasis at diagnosis. Dogs with Grade I and II tumors survived longer than dogs with Grade III tumors. Variables, including sex, age, gross versus microscopic disease, and treatment type were not found to affect survival. Local control rate was 75% at 1 year and 50% at 3 years. Tumor grade was the only variable found to affect local control. Dogs with Grade I tumors had longer disease-free intervals than those with Grade II tumors, and dogs with Grade II tumors had longer disease-free intervals than dogs with Grade III tumors. Eight of 9 dogs dying of MCT had local or regional disease progression. Muzzle MCT a rebiologically aggressive tumors with higher regional metastatic rates than previously reported for MCT in other sites.
  • Clin Tech Small Anim Pract. 2003 May;18(2):103-6. : Principles of treatment for mast cell tumors.
    Govier SM.
    Animal Medical Center, New York, NY 10021, USA.

    Mast cell tumors (MCT) are the most common malignant cutaneous tumors that occur in dogs. They are most commonly found on the trunk, accounting for approximately 50% to 60% of all sites. MCTs associated with the limbs account for approximately 25% of all sites. Cutaneous MCTs have a wide variety of clinical appearances. Histologic grade is the most consistent prognostic factor available for dogs. MCTs located at 'nail bed' (subungual), inguinal/preputial area, and any mucocutaneous area like perineum or oral cavity carry a guarded prognosis and tend to metastasize. MCTs usually exfoliate well and are cytologically distinct. The extent of staging procedures following fine-needle aspirate cytologic diagnosis is based on the presence or absence of negative prognostic indicators. Surgery is the treatment of choice for solitary MCTs with no evidence of metastasis. Reponses rates to chemotherapy, (partial response) as high as 78% have been reported, and preliminary evidence suggests that multiagent (prednisone and vinblastine) protocols may confer a higher response rate than single-agent therapy. MCTs are the second most common cutaneous tumor in the cat. There are two distinct forms of cutaneous MCTs in the cat. The more common form is the mastocytic form, and the less common is the histiocytic form. Unlike in the dog, the head and neck are the most common sites for MCTs in the cat followed by the trunk and limbs. Cats with disseminated forms of MCT often present with systemic signs of illness, which include depression, anorexia, weight loss, and vomiting. The diagnosis and staging of MCTs in cats is similar to that in the dog. As with dogs with cutaneous MCTs, surgery is the treatment of choice. Little is known about the effectiveness of adjunctive chemotherapy options for cutaneous MCTs. Adjunctive chemotherapy does not appear to increase survival times<
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    LI>Vet Clin North Am Small Anim Pract. 2003 May;33(3):473-89, v. : Mast cell tumors in the dog.
    London CA, Seguin B.
    Department of Surgical and Radiological Sciences, 2112 Tupper Hall, One Shields Avenue, University of California at Davis, Davis, CA 95616, USA.

    The most common skin tumor in dogs is the mast cell tumor (MCT), with an incidence of close to 20% in the canine population. MCTs range from relatively benign to extremely aggressive, leading to metastasis and eventual death from systemic disease. Although surgical removal with or without radiation therapy may cure most patients with low-grade MCTs, there are no effective treatments for dogs with aggressive high-grade MCTs. This article reviews the current understanding of MCT biology with regard to diagnosis, staging, identification of prognostic indicators, and appropriate treatment planning.
  • Mast cell-an overview
    Mast cells are integral in host defense mechanisms. These cells are involved in hypersensitivity reactions, acute and chronic inflammation, T-cell stimulation, and tissue defense against parasites.
    Also provides slides and more indepth but not too difficult to read
    Another overview which also discusses drugs and chemo radiation
    Mast cell tumors tend to metastasize to nodes, liver spleen and bone marrow ...rarely to lungs. Radiation therapy is extremely effective for controlling local disease.
    Abdominal radiographs may be useful in evaluating dogs and cats. This is especially true in cats because of the high incidence of splenic involvement in this species with mast cell tumors. Chest radiographs rarely identify the presence of pulmonary metastases. In cases of mast cell tumors that involve the hindlimbs, perineal or preputial area, abdominal radiographs may be helpful in detecting metastatic lymphadenopathy in the iliac and sublumbar lymph nodes.
    Tumors located in the perineal or, preputial area are likely to metastasize both locally and to deep lymph nodes.
    Dogs that have tumors that grow greater than 1 cm per week have only a 25% chance of living an additional 30 week
    mast cell
    Dogs that develop mast cell tumors often are older (usually 8 to 9 years of age), but mast cell tumors can occur in dogs of all ages. Breeds that seem predisposed include boxers, Boston terriers, bull terriers, bullmastiffs, English setters and golden retrievers. Males and females are affected equally.

    Vet Dermatol 2002 Dec;13(6):301-5 : Influence of vitamin E on mast cell mediator release. Gueck T, Aschenbach JR, Fuhrmann H.
    Institute of Physiological Chemistry, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 1, 04103 Leipzig, Germany.

    We investigated the influence of vitamin E on mediator activity and release in a canine mastocytoma cell line (C2) as a model for canine atopic dermatitis. Cells were incubated without and with vitamin E (100 microm) for 24 h. The histamine and prostaglandin D2 (PGD2) release as well as the chymase and tryptase activity were measured. To stimulate the PGD2 and histamine release, cells were incubated with the wasp venom peptide mastoparan (50 microm) for 30 or 45 min. Nonstimulated as well as mastoparan-stimulated histamine and PGD2 release was reduced significantly in vitamin E-treated cells. The activity of chymase tended to decrease, but the tryptase activity of C2 cells was not influenced by vitamin E. These results indicate that vitamin E decreased the production and release of inflammatory mediators in C2 cells, suggesting that vitamin E might have a possible beneficial effect in inflammatory diseases.
    Mast Cell Tumors-care sheet
    2. Immune suppressants: Because mast cells are white blood cells, their production can be slowed or even halted by suppressing white blood cell production. Because cancer cells are more sensitive to medication than normal cells, treating with milder immunosuppressants can treat the cancer, without adversely affecting your pet's overall health.
    . a. Prednisone: is a steroid that at higher doses can be immune suppressive. At the initial higher doses you will note increased thirst and urinations. As the doses decrease, these side effects should decrease. b. Leukeran (chlorambucil) is an immune suppressive drug used in some lymphomas that is a little stronger than prednisone, and less likely to cause increased thirst and urinations. Some dogs will not eat on leukeran, and it should not be used in cats.
    3. Tagamet: tagamet is an anti-histamine and acid blocker used to prevent stomach ulcers. Pets that have a decreased appetite, drooling, or are vomiting often improve dramatically with tagamet
    Watch for these Signs:
    *Your pet develops a moist cough or seems to be having trouble breathing.
    * Your pet has any vomiting, diarrhea, or seems nauseous or inappetant.
    *The mass returns or seems larger."

    mast cell-another good easy to read overview
  • Prognosis following surgical excision of canine cutaneous mast cell tumors with histopathologically tumor-free versus nontumor-free margins: a retrospective study of 31 cases.
    The purpose of this study was to determine if the presence of histopathologically tumor-free versus nontumor-free margins was prognostic for relapse or tumor-related death in dogs following surgical excision of single or multiple cutaneous mast cell tumors confined to the skin without evidence of metastasis to lymph nodes or other noncutaneous sites. Differences in tumor-related death or frequency of relapse between the two groups were not significant. Failure to achieve histopathological tumor-free margins frequently did not lead to local relapse. All tumor-related deaths occurred following local relapse. The lack of statistical support for an association between prognosis and histopathological tumor-free versus nontumor-free margins may be a result of small sample size.
    Results of radiation therapy in 19 dogs with cutaneous mast cell tumor and regional lymph node metastasis.
    The records of 19 dogs with cutaneous mast cell tumor and regional lymph node metastasis (WHO Stage 2) were reviewed to determine the efficacy of radiation therapy in this population. Dogs with grade I (n = 1), grade II (n = 16), and grade III (n = 2) cutaneous mast cell tumor were included in this study. All dogs were treated with a combination of pre-irradiation surgical cytoreduction of the primary tumor, irradiation of the primary tumor and regional lymph node, and oral prednisone. Total radiation dose to the primary tumor and regional lymph node ranged from 48 to 57 Gray (Gy). The medial iliac and hypogastric lymph nodes were irradiated prophylactically in 11 dogs with primary tumor of the pelvic limb and positive ipsilateral popliteal lymph node. Total radiation dose to these lymph nodes ranged from 48 to 57 Gy. For all radiation fields, dose per fraction was 3 Gy, and therapy was administered on a Monday through Friday schedule. Acute and late radiation side effects observed in this study were considered acceptable. The median disease-free survival was 1,240 days (95% confidence interval 256 to 2,391 days). The disease-free survival in dogs with stage 2 mast cell tumor suggests that the combination of surgery, irradiation, and prednisone for the primary tumor along with irradiation of the positive lymph node is effective.
    Treatment of canine mast cell tumors with CCNU (lomustine).
    The efficacy and toxicity of CCNU (1-[2-chloroethyl]3-cyclohexyl-1-nitrosourea) were evaluated in 23 dogs with measurable mast cell tumors (MCT). Twenty-two dogs had cutaneous MCT and 1 dog had an intranasal MCT Nineteen (83%) dogs had biopsy of their original mass performed and 4 (17%) had aspiration cytology of masses. Of the 19 tumors histologically graded, 1 (5%) neoplasm was classified as grade I, 10 (53%) were grade II, and the remaining 8 (42%) were grade III. Dogs were treated with CCNU at a dosage of 90 mg/m2 body surface area every 3 weeks. Response could be evaluated in 19 dogs. Eight of the 19 dogs (42%) had a measurable response to CCNU. One dog had a durable complete response for 440 days. Seven dogs (37%) had a partial response for a median and mean duration of 77 days and 109 days, respectively (range, 21-254 days). Treatment with CCNU resulted in stable disease in 6 dogs (32%) for a median and mean duration of 78 days and 122 days, respectively (range, 42-347 days). The acute dose-limiting toxicity was neutropenia 7 days after administration of CCNU. The median and mean neutrophil counts 7 days after CCNU were 1,452 cells/microL and 1,683 cells/microL, respectively (n = 17). Other toxicoses were uncommon. CCNU should be considered an active agent in the treatment of MCT in dogs.
    Phase I evaluation of CCNU (lomustine) in tumor-bearing cats.
    -(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.
  • Recurrence rates and sites for grade II canine cutaneous mast cell tumors following complete surgical excision.
    A retrospective study was performed on 31 dogs with completely excised, grade II, cutaneous mast cell tumors in order to determine recurrence rates and sites. Distant tumor recurrence developed in 22% of dogs, and local tumor recurrence developed in 11% of dogs; however, the vast majority of these animals were incompletely staged initially. Complete surgical excision of grade II mast cell tumors was associated with effective local control in 89% of these dogs. Therefore, adjuvant radiation therapy might not be indicated in the majority of dogs with complete surgical excision.
  • research study on surgery for grade II
    "Forty-six (84%) dogs were free of mast cell tumors during the study period.(540 days) A reliable prognostic factor could not be identified. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that additional local treatment may not be required after complete excision of grade-II mast cell tumors and that most dogs do not require systemic treatment. "
  • Mast Cell tumor-vetinfo
  • Sensitivity and specificity of methods of assessing the regional lymph nodes for evidence of metastasis in dogs and cats with solid tumors. Results suggested that fine-needle aspiration may be a sensitive and specific method of evaluating the regional lymph nodes in dogs and cats with solid tumors, because results correlated well with results of histologic examination of the entire lymph node. Physical examination alone was not a reliable method and should not be used to decide whether to aspirate or biopsy the regional lymph nodes."
  • Prednisone and vinblastine chemotherapy for canine mast cell tumor--41 cases (1992-1997).
    "This is an apparent improvement over historical survival data employing surgery alone. Upon univariate analysis, significant prognostic factors (P < .05) for survival included presence of a locally recurrent tumor, presence of gross disease, argyrophilic nucleolar organizer region frequency, lymph node status, histologic grade, previous chemotherapy, and ulceration of the tumor. Similar criteria were significant when analyzed for time to treatment failure. Response to therapy was also predictive of survival in the gross disease group. Upon multivariate analysis, histologic grade (P = .012) and presence of a locally recurrent tumor (P < .001) were significant factors for survival"

  • CCNU should be considered an active agent in the treatment of MCT in dogs.
  • Vincristine therapy for mast cell tumors in dogs.
    Twenty-seven dogs with naturally occurring mast cell tumors were treated with weekly i.v. injections of vincristine (0.75 mg/m2) for 4 treatments. Two dogs (7%) had a partial response. Nine dogs (32%) had treatment stopped prematurely because of toxicity or a perceived deterioration in their quality of life. We conclude that vincristine is ineffective as a sole treatment for measurable mast cell tumors in dogs and produces an undesirable number of adverse reactions.
  • mast cell tumours-canine
  • feline and canine mast cell tumors
    "Mast cell tumors are especially inflammatory tumors which contain fragile granules of histamine. Patients with mast cell tumors experience chronic inflammatory symptoms due to circulating histamine. Antihistamines such as clemastine fumarate may be helpful when given long term though less expensive medications such as diphenhydramine
  • "Virtually all commonly used chemotherapeutic agents have been described for the adjuvant treatment of dogs with mast cell tumours. None work reliably in every case. A combination of vinblastine, cyclophosphamide and prednisone shows some promise. Controversy surrounds other treatments such as deionized water injections. Often antihistamines (such as zantac, niramine) are used and these can be important to block the effects of histamine released from the granules within the mast cell cytoplasm. Radiation is useful in some settings. Unfortunately we do not have access to radiation therapy of the type necessary."
    Cutaneous mast cell tumors in cats: 32 cases (1991-1994).
    Case records of 32 cats with cutaneous mast cell tumors (CMCTs) were reviewed. Using the Patnaik system for grading canine mast cell tumors, the relationships between histopathological grade and patient survival time and tumor recurrence were examined. Tumor histopathological grade had no prognostic significance. One-, two-, and three-year tumor recurrence rates following surgical excision were 16%, 19%, and 13%, respectively. Incomplete excision was not associated with a higher rate of tumor recurrence.