Eighty-three cutaneous mast cell tumors in the dog were classified morphologically into three grades. The neoplasms were excised surgically, and the dogs were followed for 1500 days. Comparison of morphologic grade of tumor with survival time revealed significant differences among the three groups (p less than 0.00010). Comparison of sex and age (above and below ten years) with morphologic grade of tumor revealed no significant differences.

https://journals.sagepub.com/doi/pdf/10.1177/030098588402100503

Canine Cutaneous Mast Cell Tumor: Morphologic Grading and Survival Time in 83 Dogs

Follow-up studies have been conducted on 114 dogs from which mastocytomas were removed surgically, and the subsequent progress of each animal recorded. To date, 38 % of animals have died or been destroyed as a direct consequence of the neoplastic process and of these, 69 % had histologically poorly-differentiated (Grade 1), 18% intermediate (Grade 2), and 13% well-differentiated (Grade 3) tumours. The mean survival time of animals with Grade 3 tumours was 51 weeks, whilst for those which had Grade 2 or Grade 1 types it was 28 and 18 weeks respectively.



Most dogs which survive for longer than 30 weeks post-operatively appear to be cured, and on this basis the apparent cure rate for animals with Grade 3 tumours was six times greater than that for animals with Grade 1, and twice as great as that for animals with Grade 2 tumours.



Although the best method of obtaining an accurate prognosis is to submit the excised tumour for histological examination, it can be said on clinical grounds alone that if a mastocytoma has been present for more than 28 weeks before removal, the prognosis should be favourable, since 83% of animals with this history survived for more than 30 weeks post-operatively.



Resume. On a poirsuivi des recherches complementaires sur 114 chiens dont on a excise les mastocytomes. Les progres subsequents de chaque animal ont ete enregistres. Jusqu'a present, 38% des animaux sont morts ou ont ete detruits comme consequence directe du processus neoplastique, 69% de ces chiens avaient des tumeurs histologiquement assez mal differenciees (Grade 1), 18% des tumeurs intermediaires (Grade 2), et 13% des tumeurs bien differenciees (Grade 3). La periode moyenne de survie des animaux avec des tumeurs du grade 3 etait de 51 semaines tandis que pour ceux ayant des tumeurs des grades 2 et 1, cette periode etait de 28 et de 18 semaines respectivement.



La plupart des chiens qui survivent plus de 30 semaines apres l'operation, semblent gueris et sur ce principe, le taux apparent de guerison pour des animaux avec des tumeurs du grade 3 etait de 6 fois superieure a celui pour des animaux avec des tumeurs du grade 1 et deux fois aussi eleve que celui pour des animaux avec des tumeurs du grade 2.



Bien que la meilleure methode pour obtenir un prognostic correct soit de faire subir un examen histologique a la tumeur excisee, on peut dire, pour raison clinique seulement, que si un masto-cytome a ete present pendant plus de 28 semaines avant d'etre enleve, le prognostic devrait etre favorable, vu que 83% des animaux avec ce genre d'histoire ont survecu pendant plus de 30 semaines apres l'operation.



Zusammenfassung. Nachuntersuchungen wurden an 114 Hunden ausgefuhrt an denen Mas-tozytome chirurgisch beseitigt wurden und folgenden Fortschritt verzeichnete man von jedem Tier. Bis heute, krepierten oder wurden vernichtet 38% der Tiere als direkte Folge der bosartigen Gewebeneubildung und von diesen hatten 69% histologisch schlecht zu unterscheidende Tumors (Grad 1), 18% zwischenliegende Tumors (Grad 2), und 13% gut zu unterscheidende Tumors (Grad 3). Die Durchschnitts-Uberlebungszeit von Tieren mit Grad 3 Tumors war 51 Wochen, wahrend fur jene mit Grad 2 und Grad 1 Typ es jeweilig 28 und 18 Wochen waren.



Die meisten Hunde, die langer als 30 Wochen postoperativ uberleben, scheinen geheilt zu sein und aud dieser Basis war der offenbare Heilungsprozentsatz fur Tiere mit Grad 3 Tumors sechs mal grosser als der fur Tiere mit Grad 1 Tumors und zwei mal so gross als der mit Grad 2 Tumors. Obwohl die beste Methode eine akkurate Prognose zu erlangen ist den herausgeschnittenen Tumor histologischer Untersuchung zu unterwerfen, kann man durch klinische Erfahrung allein behaupten, wenn ein Mastozytom mehr as 28 Wochen vor der Entfernung vorhanden war, dass die Prognose gunstig sein musste, da 83% von Tieren mit dieser Krankheitsgeschichte mehr als 30 Wochen nachoperativ uberlebten.

The prognosis following surgical removal of mastocytomas in dogs.

In this study, age, sex, recurrence, metastasis, death rate, and histologic patterns were in agreement with those of previous reports on canine mast cell tumors. Histologic grading, mitotic index, chromosome nucleolar organizer regions stained with silver (AgNORs), and anti-proliferating cell nuclear antigen (PCNA) were evaluated as indicators of prognosis. Histologic grading, AgNORs estimated in 100 cells, and PCNA-labeled fraction estimated in five high power fields (HPFs) were significantly different between recurring and nonrecurring tumors. Those prognostic factors were also significantly different between tumors that metastasized and those that did not. The survival time was lower in dogs with mast cell tumors with histologic grade 3 (Patnaik's), AgNOR counts higher than 2.25, and PCNA count in five HPFs higher than 261. The significance of these factors as markers for prognosis determined by logistic regression analysis differed with the time period considered. By combining the three most significant prognostic factors in a prognostic index, three models were obtained to determine the probability of nonrecurrence at 3, 6, and 9 months after surgery. The models were accurate in the prediction of the outcome of up to 80% of mast cell tumors. The use of these models provides a less subjective means of prognosticating mast cell tumors than the use of any one component alone.

https://journals.sagepub.com/doi/pdf/10.1177/030098589403100602

Prognosis of Canine Mast Cell Tumors: A Comparison of Three Methods:

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 ≥ 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°, 90°, 180°, and 270°. 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 co...

Evaluation of surgical margins required for complete excision of cutaneous mast cell tumors in dogs.

Mast cell tumors (MCTs) are common in the dog, occurring most frequently in the skin and subcutaneous tissues. Their biologic behavior can be quite variable, with approximately 50% being malignant. Although clinical features and histologic grading can help determine the likelihood of malignancy, it is difficult to predict the biologic behavior of an individual tumor. Consequently, all MCTs should be considered potentially malignant. Wide surgical excision is the most common therapy for canine MCTs, although approximately 50% recur locally. Nonresectable or recurrent MCTs can be treated with radiation and/or chemotherapy. Chemotherapy is also used in the treatment of metastatic MCTs, and it may be helpful in preventing the recurrence and/or metastasis of undifferentiated tumors.

Nielsen Sw

Papers

Canine mastocytoma; a report of one hundred cases.