Читать книгу Veterinary Surgical Oncology - Группа авторов - Страница 78

The treatment of choice for nonlymphomatous colorectal tumors in dogs and cats is surgical excision. Several surgical procedures have been described, and extensive margins (from 2 to 8 cm) are recommended when considering the resection of a malignant neoplasm (Palmintieri 1966; White and Gorman 1987; Anson et al. 1988; Danova et al. 2006; Morello et al. 2008). In one study, dogs with annular, obstructing adenocarcinoma had mean survival times of 1.6 months vs. 32 months in dogs with single, pedunculated colorectal adenocarcinoma (Church et al. 1987).

Figure 3.2 Urethral stent placement (neoplastic obstruction). (a) An area of obstruction can be noted cranial to the femoral head during this contrast study. A marker catheter is present within the rectum. (b) A stent within a delivery system can be seen in the urethra. The stent has been placed over a guidewire and is starting to be deployed. (c) Complete stent deployment has occurred, and the urethral obstruction is relieved.

In humans with colorectal neoplasia, approximately 20% will present with unresectable locally advanced tumors or with metastatic disease and between 10 and 30% will have acute colonic obstruction (Athreya et al. 2006; Wasserberg and Kaufman 2007). Colonic stenting is one of the palliative treatment options that can be offered in these cases (Suzuki et al. 2004; Athreya et al. 2006; Wasserberg and Kaufman 2007). Colonic stenting is also being used in human patients prior to surgical resection (Martinez‐Santos et al. 2002; Suzuki et al. 2004). Patients with stents placed prior to definitive surgery may have lower severe complication rates and shorter hospital stays (Martinez‐Santos et al. 2002).

Currently, only three cases of colonic stenting have been reported in veterinary clinical cases (Hume et al. 2006; Culp et al. 2011). In two cats with colonic adenocarcinoma, one survived for 274 days after stent placement and experienced minimal stent‐associated side effects (occasional mild tenesmus) (Hume et al. 2006). The second was euthanized 19 days after stent placement due to a diminishing quality of life. Both cats retained fecal continence after stent placement (Hume et al. 2006). Colorectal stents may provide a viable treatment option in dogs as well (Figure 3.3). In one reported case, a stent was placed with fluoroscopic‐ and colonoscopic‐guidance, and an improvement of clinical signs was noted. The dog was euthanized at 238 days after stent placement due to worsening of clinical signs (Culp et al. 2011).

Figure 3.3 Colorectal stent (neoplastic obstruction). In this dog, a stent was placed to palliate clinical signs associated with a large annular colorectal neoplasm that extended for 8 cm and was causing colorectal obstruction. This radiograph was taken 190 days after stent placement.