Plesiotherapy

Below is a list of scientific articles that deal with plesiotherapy in dogs, cats and birds.

The articles are sorted by date with the most recent at the top. A brief description of the article follows the title.

2011/01
⁹⁰Sr Therapy for Oral Squamous Cell Carcinoma in Two Cats
Nagata K., Selting K.A., Cook C.R., et al.
Veterinary Radiology & Ultrasound, 2010.
Two cats with a superficial oral squamous cell carcinoma responded favorably to treatment using a ⁹⁰Sr probe. From one to six fields were applied per tumor, depending on tumor size. The surface dose per treatment ranged from 75 to 150 Gy and the total surface dose ranged from 200 to 500 Gy. Adverse effects were minimal. The cats survived 7 months and 5 years 9 months from the time of diagnosis. These data indicate that with careful patient selection ⁹⁰Sr may be useful for the treatment of feline oral squamous cell carcinoma in some patients.

 

2007/09
Evaluation of strontium Sr 90 for the treatment of superficial squamous cell carcinoma of the nasal planum in cats: 49 cases (1990–2006)
GM Hammond, IK Gordon, AP Theon, MS Kent
J Am Vet Med Assoc 2007;231:736–741
Objective—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 (⁹⁰Sr).
Design—Retrospective case series.
Animals—49 cats with SCC of the nasal planum.
Procedures—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), ⁹⁰Sr 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.
Results—Of 49 cats that underwent ⁹⁰Sr 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.
Conclusions and Clinical Relevance—Treatment of cats with SCC of the nasal planum with a single fraction of ⁹⁰Sr appeared to be effective and well tolerated. Initial response to treatment was predictive of overall survival time.

 

2006/09
Multiple limbal haemangiosarcomas in a border collie dog: management by lamellar keratectomy/sclerectomy and strontium-90 beta plesiotherapy.
Journal of Small Animal Practice (2006) 47, 545–549D.
DONALDSON, J. SANSOM, S. MURPHY AND T. SCASE
An eight-year-old, neutered, male border collie dog was presented with a six-week history of left ocular discomfort and a raised, red mass at the lateral limbus. The right eye had been enucleated approximately 12 months previously following suspected trauma when the eye had become red and painful. The mass was excised using superficial keratectomy/sclerectomy and the surgery site was treated with strontium-90 beta radiation. Histopathological findings were consistent with a diagnosis of haemangiosarcoma. Immunohistochemical staining showed uniform expression of CD31 in neoplastic cells, confirming their endothelial origin. Two further treatments with strontium-90 beta radiation were applied to the surgical site at weekly intervals. Twenty-six weeks after surgery, a second, raised, red limbal mass became apparent at the medial limbus of the left eye. Surgical excision and adjuvant strontium-90 beta plesiotherapy were performed as described for the initial tumour. Routine histopathological analysis confirmed haemangiosarcoma at this site. Eighty-six weeks following the initial presentation, no recurrence of ocular haemangiosarcoma was evident.

 

2006/09
Canine limbal melanoma: 30 cases (1992–2004). Part 2. Treatment with lamellar resection and adjunctive strontium-90 beta plesiotherapy – efficacy and morbidity.
Veterinary Ophthalmology (2006) 9, 3, 179–185.
David Donaldson, Jane Sansom and Vicky Adams
Abstract
Objectives
To evaluate the efficacy of lamellar resection and adjunctive Sr-90 Betaβ plesiotherapy in the management of canine limbal melanoma and the frequency and morbidity of early and late-onset side effects following treatment.
Recurrence of limbal melanoma occurred in 1 of 30 cases (3%; 95% CI: 0.2–14%). One or more side effects occurred in 16 of 30 cases (53%; 95% CI: 28.1–74.9). The occurrence of side effects was not associated with the number of sites treated or the total surface dose of radiation. Short-term side effects were reported in 16/30 cases (53%) and included corneal scarring (12/30), corneal neovascularization (6/30), conjunctivitis with or without granulation tissue formation (5/30), lipid keratopathy (1/30), and localized bullous keratopathy (2/30). Long-term side effects were reported in 6 of 30 cases (20%) cases and included deep scleral thinning (5/30), focal scleromalacia (3/30), globe perforation (2/30), lipid keratopathy (3/30), localized bullous keratopathy (1/30), and sectoral cortical cataract (1/30).
Conclusions
Lamellar resection and adjunctive 90 Sr-Betaβ plesiotherapy is relatively easy to perform, is minimally invasive, and extremely well tolerated by patients. The treatment is highly efficacious in the management of canine limbal melanoma. Modification of the radiation dosimetry, in particular reducing the total dose of radiation and the dose per radiation fraction, is necessary to reduce the incidence of late onset side effects.

 

2006/08
A retrospective study of ⁹⁰Strontium plesiotherapy for feline squamous cell of the nasal planum.
Mark Goodfellow, Alison Hayes, Sue Murphy, Malcolm Brearley
Journal of Feline Medicine and Surgery (2006) 8, 169-176
The responses of 15 cats with histologically (n= 14) or cytologically (n = 1) confirmed nasal squamous cell carcinoma treated with 90Strontium plesiotherapy were reviewed retrospectively. Cats were treated such that a total dose of 50 Gy was delivered at a depth of 2 mm, administered in five fractions over a 10-day period. Of the cats, 11 were stage T2, three were Tis and one had only a cytological diagnosis precluding staging. Eleven of the cats achieved complete response (no visible lesion after 6e8 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 134-2043 days (median 652 days). In addition to prolonged disease-free survivals, 90Strontium 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 90Strontium plesiotherapy, and this form of therapy may offer advantages over other alternatives currently available.

 

2006/03
Evaluation of strontium 90 irradiation in treatment of cutaneous mast cell tumors in cats: 35 cases (1992–2002).
Jane M. Turrel, John Farrelly, Rodney L. Page, Margaret C. McEntee
Journal of the American Veterinary Medical Association (2006) Vol 228, No 6, 898-901.
Objective—To determine the efficacy of strontium 90 β irradiation in the management of cutaneous mast cell tumors (CMCTs) in cats.
Study Design—Retrospective case series.
Animals—35 client-owned cats with CMCTs.
Procedure—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.
Results—54 tumors in 35 cats were treated with a median dose of 135 Gy of strontium 90 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.
Conclusions and Clinical Relevance—Results indicated that strontium 90 β irradiation resulted in long-term tumor control and should be considered an effective alternative to surgical resection in management of CMCTs in cats.

 

2004/07
Strontium-90 Therapy for Uropygial Neoplasia
Larry Nemetz, Michael Broome
Proceedings the annual meeting of the Association of Avian Veterinarians, 2004.
Abstract: A carcinoma and squamous cell carcinoma of the uropygial gland was diagnosed in 2 budgerigars (Melopsittacus undulatus). A papillary adenoma of the uropygial gland was diagnosed in a cockatiel (Nymphicus hollandicus). Surgical excision had been the main therapy for uropygial neoplasia but with variable success. A single irradiation fraction of 100 Gy/8.3 mm from a Strontium-90 ophthalmic applicator with or without surgical debulking was presented as a simple, viable, non-invasive method at moderate cost for the successful treatment of uropygial neoplasia.

 

1993/10
Strontium-90 Plesiotherapy For Treatment Of Early Squamous Cell Carcinomas Of The Nasal Planum In 25 Cats
M. K. Van Vechten, A. P. Theon
Proc 13th Annual Conference Veterinary Cancer Soc 107-108, 1993.
Sunlight-associated skin cancer is an important disease in animals and humans living in the arid and semi-arid regions of the world. There are several options available for treatment of cats with squamous cell carcinoma of the skin of the head. These methods include surgical excision, radiation therapy using a variety of energy sources and fractionation schedules,2A and photodynamic therapy. The purpose of this study was to determine the efficacy and toxicity of strontium-90 plesiotherapy for treatment of early carcinomas of the nasal planum in cats.
Materials and Methods
Twenty five cats were entered in the study. Cats were selected for treatment if lesions were superficial (< 3 mm depth) and general health precluded the repeated anesthetic episodes required for orthovoltage irradiation, or the owner declined orthovoltage treatment. The cats ranged in age from 4 to 19 years (mean 10.6 years). The female to male ratio was 1.3. All cats were FeLV negative but 2 (2/14 cats tested) were FIV positive. Eighteen cats with histologically confirmed squamous cell carcinomas and 7 cats with chronic (> 3 months) ulcerative lesions were entered in the study. All lesions were classified TlNOMO using the TNM (Tumor, Node, Metastasis) classification system of the World Health Organization. Eight cats had previous treatment including surgery, cryotherapy, hyperthermia and photodynamic therapy. Irradiation was done with a wSr-v &ray ophthalmic applicator (Nuclear Associates, NY). The applicator had a circular source with an activity of 3.4 109 Bq and an active diameter of 8.7 mm. The beta dose rate at the surface of the source was 47 Gy/minute. Treatment dose was 200 Gy (surface dose) given using a single field (n = 17), 2 fields (n =5) and 3 fields (n = 3). Endpoints evaluated were 1) progression-free survival (PFS) time after irradiation and 2) acute and late toxicities. 8 Mw and median follow-up after treatment were 19 and 16 months respectively. PFS rates were computed using the product-limit method. The RTOG/EORTC scoring scheme was used to analyze acute and late morbidity.”
The product-limit estimates of the mean (& SE) PFS times was 34 (& 3) months. The l-year and 3-year estimates (*SE) of PFS rates were 89 (k7)% and 82 (kg) %. Three cats had tumor recurrence at 12 (2) and 17 (1) months after treatment. Two cats were retreated successfully and 1 cat was lost to follow up.
Acute radiation reactions were mild and self-limiting. Chronic radiation reactions were not observed in the follow up period.