Permanent I-125 Seed Implant in the Treatment of Squamous Cell Carcinoma in an Atlantic Bottlenose Dolphin, Tursiops truncatus
A 27-year-old female Atlantic Bottlenose Dolphin (Tursiops truncatus) diagnosed with malignant squamous cell carcinoma (SCC) of the oral cavity four years previously was treated with a permanent brachytherapy implant using Iodine-125 seeds. The tumor invaded the intermandibular space and undermined the tongue. Because of the advanced nature of the tumor at the time of diagnosis, the initial treatment plan was to de-bulk the tumor and to attain local control. Surgical laser3, intra-lesional chemotherapy2 and cryotherapy were used. Although partial remission of the primary tumor was achieved, the tumor grew aggressively during and following a pregnancy.
Brachytherapy involves the implantation of radioactive sources directly into tumor. It has been utilized for more than 100 years in successful treatment of cancers in such areas as the prostate, head and neck, and soft tissue sarcomas1. The use of brachytherapy in this case obviated the need for what would have been several weeks of external beam therapy, avoiding multiple sedations. I-125 sources were chosen because of radiation safety issues and the ability to minimize shielding requirements. The sources were imbedded in absorbable sutures and implanted according to a prearranged 3-Dimensional treatment plan.
Prior to initiating this process for the radioactive seed implant, The Queen's Medical Center obtained an amendment to its Nuclear Regulatory Commission license to allow a single episode of implantation of I-125 sources into the dolphin.
3-Dimensional imaging was performed in order to identify the tumor volume. A 3-Dimensional computerized planning system was used to design the source placement and to select the proper number of seeds and seed activity. Prior to the implant, three titanium marker seeds were placed into the tumor to use as reference points for the scanning.
The actual percutaneous implantation of the I-125 sources will be described as well as patient monitoring, follow up care and treatment outcome.
The Queen's Medical Center, Honolulu, Hawaii Donna Christle, Queens Medical Center, Honolulu, Hawaii Radiation Oncology Department, Queen's Medical Center Sandy Labat, Oncura (an Amersham Company) Genine Gorman, RN, MSN Queens Medical Center, Honolulu, Hawaii David Quist, Sonasite Sam Ridgway, US Navy Marine Mammal Program US Army Medical Vet Corp Sam Dover, Santa Barbara, California Laboratory Animal Services, University of Hawaii at Manoa, Honolulu, Hawaii Jeffrey Pawloski, Sea Life Park, Waimanalo, Hawaii Emergency Medical Services, Honolulu, Hawaii.
1. Beitler JJ, Vikram BV, Levendag PC. 1997. Brachytherapy for cancer of the head and neck. In: Nag, S. (ed.): Principles and Practice of Brachytherapy. Futura Publishing Co., Inc., Armonk, NY. Pp. 269-290.
2. McKinnie CJ, SR Dover, GD Bossart, G Ogilvie. Treatment of oral squamous cell carcinoma in Atlantic bottlenose dolphin (Tursiops truncatus). Abstr. Proc. Intern. Assoc. of Aquatic Anim. Med. 2001. Pp. 37-38.
3. McKinnie CJ, SR Dover. Diagnosis and treatment of lingual carcinoma in an Atlantic bottlenose dolphin (Tursiops truncatus). Abstr. Proc. Intern. Assoc. of Aquatic Anim. Med. 2003. Pp. 164-165.