strontium-radioisotopes and Cat-Diseases

The main aim of the study was to establish response, disease-free interval (DFI) and overall survival of cats with nasal planum squamous cell carcinoma (SCC) treated with Sr90 plesiotherapy. A secondary aim was to determine whether a fractionated protocol is more effective than a single-dose protocol in terms of response, DFI and overall survival. The third aim was to evaluate whether we can identify prognostic factors that influence overall survival.. This was a retrospective study that included cats with a diagnosis of nasal planum SCC treated with Sr90 plesiotherapy at a single institution.. Seventy-four cats were included in the study. Thirty-two were treated with a fractionated protocol and 42 with a single-dose treatment. Sr90 plesiotherapy was able to induce complete response in 74% of cats with nasal planum SCC. The median DFI was 780 days (95% confidence interval [CI] 383-1177), with 17% of cats experiencing local recurrence. The overall survival for all cats was 1039 days (95% CI 55-1528). The DFI of cats treated with the fractionated Sr90 was significantly longer compared with the single-dose treatment, whereas response and overall survival were not statistically different. Other prognostic factors that influenced the overall survival were early-stage disease, absence of concurrent problems and complete response to the treatment. Acute and long-term toxicity associated with the treatment were minimal and the aesthetic outcome was pleasing in almost all cases.. Strontium plesiotherapy is a safe and effective treatment of nasal planum SCC in cats.

Topics: Animals; Carcinoma, Squamous Cell; Cat Diseases; Cats; Disease-Free Survival; Dose Fractionation, Radiation; Nose Neoplasms; Retrospective Studies; Strontium Radioisotopes

To determine progression-free and overall survival times of cats with squamous cell carcinoma (SCC) of the nasal planum following treatment with a single fraction of strontium Sr 90 ((90)Sr).. Retrospective case series.. 49 cats with SCC of the nasal planum.. Information including FIV infection status, diagnosis of SCC vs SCC in situ (ie, evidence that the tumor did or did not penetrate the epidermal basement membrane, respectively), (90)Sr dose and number of probe applications, treatment-related response and complications, and recurrence of SCC and new lesion development was obtained from medical records. The relationships of these variables with calculated progression-free and overall survival times were assessed.. Of 49 cats that underwent (90)Sr plesiotherapy (median dose, 128 Gy), 48 (98%) had a response to treatment and 43 (88%) had a complete response. Median progression-free and overall survival times were 1,710 and 3,076 days, respectively. Treatment complications were infrequent (4 [8%] cats) and mild. Following treatment, the SCC recurrence rate was 20% (10/49 cats); 16 (33%) cats developed new lesions in other locations. Overall survival time was significantly longer for cats with a complete response to treatment than for those with a partial response. None of the other variables evaluated had a significant effect on progression-free or overall survival time.. Treatment of cats with SCC of the nasal planum with a single fraction of (90)Sr appeared to be effective and well tolerated. Initial response to treatment was predictive of overall survival time.

Topics: Animals; Antineoplastic Agents; Carcinoma, Squamous Cell; Cat Diseases; Cats; Disease-Free Survival; Dose-Response Relationship, Radiation; Female; Male; Nose Neoplasms; Radiotherapy Dosage; Retrospective Studies; Strontium Radioisotopes; Treatment Outcome

The responses of 15 cats with histologically (n=14) or cytologically (n=1) confirmed nasal squamous cell carcinoma treated with (90)Strontium plesiotherapy were reviewed retrospectively. Cats were treated such that a total dose of 50Gy was delivered at a depth of 2mm, administered in five fractions over a 10-day period. Of the cats, 11 were stage T(2), three were T(is) and one had only a cytological diagnosis precluding staging. Eleven of the cats achieved complete response (no visible lesion after 6-8 weeks) following the first cycle of therapy, and two cats with partial response achieved complete response with a second cycle of therapy. The remaining two cats achieved partial response following therapy, but further intervention was declined. Euthanasia was performed in these two cats because of progressive disease after 81 and 142 days. Of the 85% of cats that achieved a complete response, there was no recurrence of disease during a follow-up period of 134-2,043 days (median 652 days). In addition to prolonged disease-free survivals, (90)Strontium therapy produced excellent cosmetic results from the owners' perspective. These results demonstrate that superficial squamous cell carcinoma of the feline nasal planum responds excellently to (90)Strontium plesiotherapy, and this form of therapy may offer advantages over other alternatives currently available.

Topics: Animals; Carcinoma, Squamous Cell; Cat Diseases; Cats; Dose-Response Relationship, Radiation; Female; Male; Nose Neoplasms; Radiotherapy Dosage; Retrospective Studies; Strontium Radioisotopes; Treatment Outcome

To determine the efficacy of strontium 90 beta irradiation in the management of cutaneous mast cell tumors (CMCTs) in cats.. Retrospective case series.. 35 client-owned cats with CMCTs.. Medical records of cats with CMCTs in which tumors were radiated by use of a strontium 90 ophthalmic applicator from 1992 to 2002 were reviewed. Cats were included if CMCT was diagnosed, there were no other sites of MCT involvement at the time of treatment, and records contained adequate follow-up information to permit retrospective assessment of local tumor control.. 54 tumors in 35 cats were treated with a median dose of 135 Gy of strontium 90 beta irradiation, resulting in local tumor control in 53 of 54 (98%) tumors with a median follow-up time of 783 days after treatment. Median survival time was 1,075 days. Adverse effects of treatment appeared to be infrequent and of mild severity.. Results indicated that strontium 90 beta irradiation resulted in long-term tumor control and should be considered an effective alternative to surgical resection in management of CMCTs in cats.

Topics: Animals; Cat Diseases; Cats; Dose-Response Relationship, Radiation; Female; Male; Mast-Cell Sarcoma; Retrospective Studies; Skin Neoplasms; Strontium Radioisotopes; Survival Analysis; Time Factors; Treatment Outcome

Topics: Animals; Cat Diseases; Cats; Hyperplasia; Inclusion Bodies; Mast Cells; Mast-Cell Sarcoma; Microscopy, Electron; Mitochondria; Radiation Effects; Strontium Radioisotopes