Post-surgical outcome and prognostic factors in canine malignant melanomas of the haired skin: 87 cases (2003-2015).

The medical records of 87 dogs treated with surgery for cutaneous malignant melanoma (CMM) of the haired skin were retrospectively reviewed for overall survival time (OST), progression-free survival time (PFS), and prognostic factors. The post-surgery median PFS and median OST were 1282 days and 1363 days, respectively. The post-surgery metastatic rate was 21.8% with a local recurrence rate of 8%. Increasing mitotic index (MI) was predictive of a significantly decreased OST and PFS on multivariable analysis [hazard ratio (HR): 1.05, 95% confidence interval (CI): 1.02 to 1.07 and HR: 1.04, 95% CI: 1.02 to 1.06, respectively]. Increasing age was likewise predictive of a significantly decreased OST and PFS on multivariable analysis (HR: 1.39, 95% CI: 1.17 to 1.65 and HR: 1.33, 95% CI: 1.14 to 1.54, respectively). These results confirm clinical impressions that long survival times are likely in dogs diagnosed with malignant melanoma of the haired skin when treated with surgery alone.

Résultat post-chirurgical et facteurs de pronostic pour les mélanomes malins canins de la peau poilue : 87 cas (2003­2015). Les dossiers médicaux de 87 chiens traités à l'aide d'une chirurgie pour le mélanome malin cutané (MMC) de la peau poilue ont été évalués rétrospectivement pour le temps de survie global (TSG), le temps de survie sans progression (TSSP) et les facteurs de pronostic. Le TSSP médian après la chirurgie et le TSG médian étaient de 1282 jours et de 1363 jours, respectivement. Le taux métastasique après la chirurgie était de 21,8 % avec un taux de récurrence local de 8 %. L'augmentation de l'indice mitotique (IM) était prédictive d'un TSG et d'un TSSP réduits à l'analyse multivariable (ratio de risque [RR] : 1,05, intervalle de confiance [IC] de 95 % : 1,02 à 1,07 et RR : 1,04, IC de 95 % : 1,02 à 1,06, respectivement). La progression de l'âge était aussi prédictive d'une réduction importante du TSG et du TSSP à l'analyse multivariable (RR : 1,39, IC de 95 % : 1,17 à 1,65 et RR : 1,33, IC de 95 % : 1,14 à 1,54, respectivement). Ces résultats confirment les impressions cliniques que des longs délais de survie sont probables chez les chiens diagnostiqués avec le mélanome malin de la peau poilue lorsqu'ils sont uniquement traités à l'aide d'une chirurgie.(Traduit par Isabelle Vallières).

A retrospective Italian Society of Veterinary Oncology (SIONCOV) study of 56 cats with appendicular osteosarcoma.

Osteosarcoma is the most common malignant primary bone cancer, but it is infrequently reported in cats. Feline appendicular osteosarcoma typically exhibits good prognosis when treated with surgery alone. A retrospective multi-institutional study was conducted to identify possible prognostic factors. Cats diagnosed with appendicular osteosarcoma were included if initial staging and follow-up information were available. Data including signalment, tumour characteristics, treatment modalities, and survival outcomes were collected and analysed. Fifty-six cats were included; the femur was the most frequently affected bone. Eight cats had distant metastasis at admission and an additional 9 developed metastatic disease during follow-up, resulting in an overall metastatic rate of 30%. Forty-nine (87.5%) cats underwent surgery, and 4 also received adjuvant chemotherapy. Among operated cats, median time to local progression (TTLP), time to distant progression and tumour-specific survival (TSS) were not reached. One- and 2-year survival rates were 66% and 55%, respectively. Seven (12.5%) cats received no treatment; 1- and 2-year survival rates were 25% and 0%, respectively. Operated cats had significantly longer TTLP (P < .001) and TSS (P = .001) compared with non-operated cats. Among operated cats, young age negatively impacted local tumour progression, while the presence of distant metastasis at diagnosis was associated with a higher risk of tumour-related death. This study reaffirms the good prognosis for cats with appendicular osteosarcoma undergoing surgery, but sheds light on some additional factors to consider. Accurate initial staging is recommended, as the metastatic rate may exceed many previous estimations. Surgery substantially extends survival time, whereas the role of chemotherapy remains uncertain.

Sentinel lymph node mapping in canine mast cell tumours using a preoperative radiographic indirect lymphography: Technique description and results in 138 cases.

Several sentinel lymph node (SLN) mapping techniques, to detect nodal metastasis in canine tumours have been investigated in the last 10 years in veterinary oncology. The purpose of this prospective study was to describe a reliable, quick, and inexpensive technique for SLN mapping in canine patients affected by cutaneous and subcutaneous mast cell tumours (MCT). Eighty dogs were enrolled in this study for a total of 138 cytologically diagnosed MCTs. Sentinel lymph node mapping was performed by injecting iomeprole peritumorally followed by serial radiographs at 1, 3, 6 and 9-min post injection. A total of 168 SLNs were detected, 90% at first radiograph, 1 min after the peritumoral iomeprole injection, while in the rest of the cases SLN was identified at 3 min. Sentinel lymph nodes detected by the preoperative radiographic indirect lymphography with iomeprole (PRILI) differed from regional lymph nodes in 57% of cases. The PRILI technique detected simultaneously multiple SLNs in the 26% of cases and multiple lymph centers in the 31% of MCTs. To allow the surgical identification of the SLNs, a peritumoral injection of methylene blue was performed at the time of surgery. This study reports a widely available technique for SLN mapping using digital radiographs in combination with a water-soluble medium, representing a cost-effective alternative to other SLN mapping procedures. Based on our results, this technique can be effective for SLNs mapping in dogs with MCTs but further comparative studies are needed to assess its reliability and efficacy in different tumours.

Subcutaneous mast cell tumours: A prospective multi-institutional clinicopathological and prognostic study of 43 dogs.

BACKGROUND: Canine subcutaneous mast cell tumours (ScMCTs) reportedly have a good prognosis. However, biomarkers that can be used to predict outcome are currently limited. METHODS: A multicentre prospective study was conducted to identify new prognostic markers. Dogs with a first occurrence of ScMCT were enrolled upon primary tumour removal and regional lymphadenectomy. In the absence of metastasis, dogs were monitored, while dogs with overtly metastatic lymph nodes (histological node 3, HN3) received adjuvant vinblastine. RESULTS: Forty-three dogs were enrolled: 15 (34.9%) had at least one HN3 lymph node and received vinblastine, and 28 (65.1%) were monitored. Three tumours harboured exon 8 and 9 c-kit mutations. Eight (18.6%) dogs experienced tumour progression, and five (11.6%) died of MCT-related causes. The 1- and 2-year survival rates were 90% and 77%, respectively. Variables significantly associated with an increased risk of progression included high cytograde, a mitotic count (MC) greater than 4/10 high-power fields (hpf) and Ki67-index greater than 23. An MC greater than 4/10 hpf was also associated with an increased risk of tumour-related death. LIMITATIONS: Regional rather than sentinel lymphadenectomy was performed in these dogs. Dogs were enrolled in oncology referral centres, constituting a different population compared to previous studies. CONCLUSIONS: ScMCTs have a good prognosis. However, the metastatic rate at admission was higher in this study than previously reported, and a subset of tumours were associated with a fatal outcome despite multimodal treatment. Proliferative activity and cytograding may predict more aggressive behaviour in ScMCTs.

Outcome with surgical treatment of canine soft tissue sarcoma in the region of the ischiatic tuberosity: A veterinary society of surgical oncology retrospective study.

The aim of this study was to determine the outcome of dogs with soft tissue sarcoma (STS) within the region of the ischiatic tuberosity (ITSTS) treated surgically. This was a multi-institutional retrospective study. Fifty-two dogs met the inclusion criteria, which were: histologically confirmed STS in the region of the IT treated with surgical resection between March 1st, 2009 and March 1st, 2021 with a minimum follow-up time of 6 months. Data collected included patient signalment, preoperative diagnostics, surgical intent/method, surgical complications, histopathology, margins, outcome and cause of death. Statistical analyses were performed to determine significant factors in the treatment and prognosis of ITSTS. Overall survival time (OST) and disease progression were negatively associated with tumour grade, while recurrence was positively associated with grade and incomplete margins. Of the 52 included dogs, there were 24 grade I, 20 grade II and 7 grade III tumours. Forty dogs had reported histopathologic margins of which 26 were reported to be complete and 14 were incomplete. OST and progression-free survival was not reached for tumours graded as I or II and was 255 and 268 days respectively, for grade III. Median time to recurrence was not reached for tumours excised with complete margins and was 398 days for those with incomplete margins. The surgical complication rate was 25%. ITSTS was not found to be a unique clinical entity in dogs as tumour behavior, treatment recommendations, and prognosis were similar to STS in other locations, with overall outcome and prognosis influenced by histologic grade and margins. While surgical complications were common, none resulted in significant morbidity or mortality.

Clinicopathologic features and biologic behavior of canine splenic nodules with stromal, histiocytic and lymphoid components.

The term fibrohistiocytic nodule has been discouraged in favor of specific pathologic entities, including complex nodular hyperplasia, splenic stromal sarcoma and histiocytic sarcoma. Nevertheless, the diagnosis of splenic lesions with mixed stromal, histiocytic and lymphoid components still remains a challenge due to lack of straightforward histologic criteria. Misestimation of the biologic behavior of these lesions may lead to detrimental consequences on the clinical management of patients. In this study, we retrospectively evaluated the clinicopathologic features and outcome of canine splenic nodular lesions with mixed components, to identify prognostic factors and histologic criteria of malignancy. Thirty-seven cases were included. Immunohistochemistry did not allow for further subclassification. Nine (24.3%) dogs died from disease-related causes after a median of 234 days (range, 48-1,247). One-, 2- and 3-year disease-specific survival rates were 80, 60, and 43%, respectively. When considering nodules with stromal cell atypia and at least one of mitotic count ≥9, presence of karyomegaly/multinucleated cells and lymphoid component <40%, half of these dogs died of disease-related causes with a median disease-specific survival time of 548 days (95% CI, 0-1216). In the remaining dogs, no disease-related death was reported (P < 0.001). Canine splenic nodular lesions with mixed stromal, histiocytic and lymphoid components and histologic criteria of malignancy may behave aggressively, leading to distant metastasis and death. In the absence of further criteria aiding their classification, and to better characterize their biologic behavior, we encourage the distinction of these complex splenic tumors from conventional sarcomas and histiocytic sarcomas.

Evaluation of the neoplastic infiltration of the skin overlying canine subcutaneous soft tissue sarcomas: An explorative study.

Studies regarding the neoplastic infiltration of the skin overlying canine subcutaneous soft tissue sarcoma (sSTS) are lacking. In case of the absence of tumor infiltration, there would be the possibility of leaving this unaffected skin in place, thus simplifying surgery. The aim of the study was to investigate whether the skin overlying sSTSs is infiltrated by neoplastic cells. Dogs with sSTSs treated surgically were prospectively enrolled. After excision, the skin was dissected from the tumor along the natural surgical plane of cleavage and histologically evaluated. Twenty-nine dogs with an sSTS were included (22 grade I, 6 grade II, and 1 grade III). The sSTS-overlying skin was not tumor-infiltrated in 14/29 cases (48.3%). A higher frequency of infiltration was observed in higher grade sSTSs (grades II and III, 100%; P = .006); nevertheless, 8/22 grade I sSTSs (36%) also showed cutaneous infiltration. This infiltration involved the dermis of the skin directly in contact with the tumor (multifocal in 11 and diffuse in four cases). Although the cutaneous tumor infiltration is less frequent in grade I sSTSs and a wide excision may still be the safest treatment for any sSTS for a greater possibility of local control, this study opens the possibility to a less aggressive cutaneous excision, but still with a local curative intent, as only the skin directly in contact with the sSTS has been proven to be tumor-infiltrated. Additional studies are warranted to confirm that excision of only this skin may guarantee a complete local control, especially in lower-grade sSTSs.

Clinical Features and Outcome of 79 Dogs With Digital Squamous Cell Carcinoma Undergoing Treatment: A SIONCOV Observational Study.

In dogs, digit squamous cell carcinoma (SCC) is uncommon. Clinical signs are frequently underestimated, leading to a diagnostic delay. The purpose of this retrospective study was to report our experience regarding the clinical presentation, diagnostic work-up, treatment and outcome of 79 client-owned dogs with SCC of the digit. The greatest majority (84.8%) of dogs was dark-coated. Schnauzers represented approximately one third of the study population, and had a poorer outcome compared with other breeds. The majority of SCCs occurred in the front limbs (61%), and bone lysis was frequently observed (92.4%). Approximately 9% of dogs had involvement of multiple digits, and this was associated with a shorter time to progression (TTP; P = 0.047). Similarly, a duration of clinical signs >90 days was associated with a shorter TTP (P = 0.02). Regional lymph node metastases were documented in 17.7% of dogs at admission and were significantly associated with tumor-related death (P < 0.001). At presentation, none of the dogs had evidence of distant metastasis. Digit amputation achieved adequate local tumor control in the majority of cases. Adjuvant chemotherapy and radiation therapy were carried out in 21.5% of cases, with uncertain benefit. Due to the relatively non-aggressive clinical behavior of digit SCC, chemotherapy should only be offered in the case of metastatic disease. Approximately one fourth of dogs developed de novo SCCs during the follow-up. Careful examination of the digits should be encouraged in breeds considered at high risk and in dogs with a previous history of digital SCC.

Cutaneous metastases of prostatic adenocarcinoma in two dogs.

Canine prostatic adenocarcinoma is an aggressive malignancy characterized by rapid growth, local invasiveness, and early metastatic spread. Metastases of prostatic cancer are generally diffuse at the time of diagnosis due to hematogenous or lymphatic spread and by direct exfoliation of neoplastic cells into the peritoneal cavity. Here we describe two dogs with prostatic adenocarcinoma and skin metastases. The first was a 12-year-old intact male German Shepherd dog that was presented with a history of chronic prostatic disease and multiple skin nodules that recently appeared on the ventral abdomen. The second was an 8-year-old intact male mixed breed dog that was referred for a neurologic examination because of a 1-month history of back pain and kyphosis of undefined origin. Cutaneous cytology of the first case was suggestive of carcinoma, and at necropsy, prostatic adenocarcinoma with metastases to the skin, spleen, liver, pancreas, kidneys, and lungs were found. In the second case, a computed tomographic examination revealed a prostatic neoplasm with inguinal, subcutaneous, and cutaneous nodular metastases. Cytology and histopathology were suggestive of primary prostatic adenocarcinoma with cutaneous and subcutaneous metastases. To the authors' knowledge, these are the first reported cases of prostatic adenocarcinoma skin metastases in dogs with cytologic descriptions.

Adjuvant anthracycline-based vs metronomic chemotherapy vs no medical treatment for dogs with metastatic splenic hemangiosarcoma: A multi-institutional retrospective study of the Italian Society of Veterinary Oncology.

Treatment options for dogs with metastatic (stage III) splenic hemangiosarcoma are limited. A doxorubicin-based chemotherapy regimen is commonly administered; however, there are no published data to support this practice. The aim of this study was to investigate the impact of maximum-tolerated-dose chemotherapy (MTD), metronomic chemotherapy (MC) and no adjuvant treatment on outcome in dogs with stage III splenic hemangiosarcoma undergoing splenectomy. Medical records of dogs with stage III splenic hemangiosarcoma that underwent splenectomy followed by MTD chemotherapy, MC or no adjuvant treatment were retrieved. Time to progression (TTP), survival time (ST) and toxicity were evaluated. One hundred three dogs were identified: 23 received adjuvant MTD, 38 MC and 42 were not medically treated. Overall median TTP and ST were 50 (95% confidence interval [CI], 39-61) and 55 days (95% CI, 43-66), respectively. Dogs treated with adjuvant MTD had a significantly longer TTP and ST compared with dogs receiving MC (median TTP, 134 vs 52 days, P = .025; median ST, 140 vs 58 days, P = .023, respectively). Dogs treated by splenectomy only had the shortest median TTP (28 days) and ST (40 days). However, treatment-related adverse events (AEs) were significantly more frequent in the MTD group (P = .017). The outcome for dogs with metastatic splenic hemangiosarcoma is poor. While MTD showed greater efficacy compared to MC, toxicity was higher in this group. Treatment-related AEs need to be carefully balanced against this modest survival prolongation when offering adjuvant MTD to dogs with advanced stage hemangiosarcoma.

Therapeutic impact of regional lymphadenectomy in canine stage II cutaneous mast cell tumours.

Lymph node (LN) metastasis in canine cutaneous mast cell tumours (cMCTs) is a well-known negative prognostic factor. The role of lymphadenectomy in the treatment of stage II disease remains controversial because of its uncertain therapeutic benefit. Aim of this retrospective study was to investigate the impact of lymphadenectomy on tumour control and survival for dogs with stage II cMCTs. Dogs with firstly occurring, histologically confirmed cMCT with LN metastasis undergoing resection of the primary tumour and medical treatment thereafter were retrospectively enrolled. Dogs were classified into two groups: LN sampling (LNS; diagnosis of metastasis obtained by cytology) and regional LN dissection (LND; diagnosis obtained by histopathology). To determine the therapeutic value of lymphadenectomy, the characteristics of recurrence (local, nodal and distant) and survival were compared between groups. Evaluated outcome variables included signalment, anatomic location, diameter, ulceration, substage, surgical margins, Patnaik grading, Kiupel grading and medical treatment. Overall, 152 dogs were included: 81 underwent LND as part of primary surgery and 71 LNS. The median follow-up time was 409 days for LND group and 620 days for LNS group. On univariable analysis, the risk of developing local, nodal or distant relapse was significantly higher in the LNS group compared with LND (P < 0.001). On multivariable analysis, the risk of tumour progression and tumour-related death were 5.47 and 3.61 times higher in the LNS group, respectively (P < 0.001). Regional lymphadenectomy may have therapeutic value and improve prognosis in dogs with stage II cMCTs undergoing surgical removal of the primary tumour and medical treatment.

Comparison of 2- and 3-category histologic grading systems for predicting the presence of metastasis at the time of initial evaluation in dogs with cutaneous mast cell tumors: 386 cases (2009-2014).

OBJECTIVE: To compare the Kiupel (2 categories) and Patnaik (3 categories) histologic grading systems for predicting the presence of metastasis at the time of initial examination in dogs with cutaneous mast cell tumors (MCTs). DESIGN: Retrospective case series. ANIMALS: 386 client-owned dogs with cutaneous MCTs. PROCEDURES: Medical records of dogs with newly diagnosed, histologically confirmed cutaneous MCTs that had undergone complete clinical staging were reviewed for clinical and histopathologic data. RESULTS: All Patnaik grade 1 MCTs (n = 52) were classified as Kiupel low-grade MCTs, and all Patnaik grade 3 MCTs (43) were classified as Kiupel high-grade MCTs. Of the 291 Patnaik grade 2 MCTs, 243 (83.5%) were classified as Kiupel low-grade tumors, and 48 (16.5%) were classified as Kiupel high-grade MCTs. Dogs with Patnaik grade 3 MCTs were significantly more likely to have metastases at the time of initial examination than were dogs with grade 1 or 2 MCTs (OR, 5.46), and dogs with Kiupel high-grade MCTs were significantly more likely to have metastases than were dogs with Kiupel low-grade MCTs (OR, 2.54). However, 3 of 52 (5.8%) dogs with Patnaik grade 1 tumors, 48 of 291 (16.5%) dogs with Patnaik grade 2 tumors, and 44 of 295 (14.9%) dogs with Kiupel low-grade tumors had metastatic disease. CONCLUSIONS AND CLINICAL RELEVANCE: Findings indicated that in dogs with cutaneous MCTs, prognostication should not rely on histologic grade alone, regardless of grading system used, but should take into account results of clinical staging.

Complications and outcomes following rectal pull-through surgery in dogs with rectal masses: 74 cases (2000-2013).

OBJECTIVE: To evaluate the incidence of and factors associated with complications following rectal pull-through (RPT) surgery and the outcome for dogs with rectal tumors. DESIGN: Retrospective case series. ANIMALS: 74 dogs with rectal masses. PROCEDURES: Information regarding signalment, history, diagnostic testing, type of rectal disease, surgical details, and postoperative complications, treatments, and outcomes was obtained from medical records and follow-up communications. Survival times were calculated. Descriptive statistics were generated. Regression analyses were used to evaluate the effect of various variables on the development of postsurgical complications and survival time. RESULTS: 58 (78.4%) dogs developed postsurgical complications, the most common of which was fecal incontinence with 42 (56.8%) dogs affected, of which 23 (54.8%) developed permanent incontinence. Other complications included diarrhea (n = 32), tenesmus (23), stricture formation (16), rectal bleeding (8), constipation (7), dehiscence (6), and infection (4). The rectal tumor recurred in 10 dogs. The median survival time was 1,150 days for all dogs and 726 days for dogs with malignant tumors. The 2 most common rectal masses were rectal carcinoma and rectal carcinoma in situ, and the dogs with these tumors had median survival times of 696 and 1,006 days, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Dogs with rectal diseases that underwent RPT surgery had a high incidence of complications; however, those dogs had good local tumor control and survival times. The risk and impact of postsurgical complications on the quality of life and oncological outcomes should be discussed with owners before RPT surgery is performed in dogs with rectal masses.