Page 1354 - Clinical Small Animal Internal Medicine

1292 Section 11 Oncologic Disease

Recurrence of clinical signs is uncommon with removal status, substage, anatomic site, and chemotherapy
VetBooks.ir of colorectal adenomatous polyps (17%). However, protocols that include doxorubicin have been linked to
remission duration and survival. Unlike dogs, immu-
recurrence of clinical signs after removal of carcinoma in
situ is fairly common (55%). The presence of multiple
in cats with lymphoma.
lesions was also associated with recurrence of clinical nophenotype (T cell vs B cell) is not a prognostic factor
signs. Malignant transformation has been reported with The prognosis can be fairly good for cats with small
rectal polyps, although more commonly with carcinoma intestinal adenocarcinoma that survive the postopera-
in situ (17–50%). tive period, with average survival times of 15 months
The prognosis for dogs with colorectal adenocarci- reported. In one study, even those that had lymph node
noma has been linked to the gross appearance of the metastasis at the time of surgery and survived the perio-
tumor. The mean survival time for those with peduncu- perative period fared well (average survival time of 12
lated lesions is 32 months, cobblestone lesions 12 months). In the study, recurrent adenocarcinoma was
months, and annular lesions 1.6 months. the cause of death in 50% of long‐term survivors.
Cats with small cell, low‐grade intestinal lymphoma The prognosis for intestinal mast cell tumor has
treated with prednisone and chlorambucil have a good historically been considered to be poor due to the high
prognosis with response rates of 69–95% and median percentage of patients that present with metastatic dis-
survival times of 18–24 months. ease. However, a recent study of cats indicated that the
Cats with intermediate to high‐grade intestinal lym- prognosis may be better than once thought (median sur-
phoma have a worse prognosis compared to those with vival time 531 days).
the low‐grade intestinal type. When compared to other Reported cats that had subtotal colectomy for colonic
anatomic sites, cats with intermediate to high‐grade adenocarcinoma had significantly longer survival times
intestinal lymphoma tend to have the second best prog- than cats with either mass resection or biopsy. Median
nosis, after nasal lymphoma. However, the response survival time with subtotal colectomy was 138 days ver-

rate, remission duration, and survival time for cats with sus 68 days and 10 days for mass resection and biopsy
intermediate to high‐grade intestinal lymphoma are gen- respectively. In the study, the presence of metastasis was
erally less than dogs with multicentric intermediate to also associated with a shorter survival time (median sur-
high‐grade lymphoma. The response rate for cats treated vival time 49 days) compared to those cats that did not
with multiagent (CHOP‐based) chemotherapy is 50–86% have metastasis (259 days). Finally, cats that receive dox-
(complete response rate of 50–70%) with a median orubicin chemotherapy appear to have a significantly
remission duration of 4–9 months and a median survival longer survival time (median survival 280 days) com-
time of up to 7–9 months. Response to therapy, FeLV pared to those that do not receive doxorubicin (56 days).

Further Reading

Culp WT, Drobatz KJ, Glassman MM, et al. Feline Kiselow MA, Rassnick KM, McDonough SP, et al.
visceral hemangiosarcoma. J Vet Intern Med 2008; Outcomes of cats with low‐grade lymphocytic
22: 149–52. lymphoma: 41 cases (1995–2005). J Am Vet Med Assoc
Daters AT, Mauldin GE, Mauldin GN, et al. Evaluation 2008; 232: 405–10.
of a multidrug chemotherapy protocol with Rassnick KM, Moore AS, Collister KE, et al. Efficacy of
mitoxantrone based maintenance (CHOP‐MA) for combination chemotherapy for treatment of
the treatment of canine lymphoma. Vet Comp Oncol gastrointestinal lymphoma in dogs. J Vet Intern Med
2010; 8: 11–22. 2009; 23: 317–22.
Gregory‐Bryson E, Bartlett E, Kiupel M, et al. Canine Russell KN, Mehler SJ, Skorupski KA, et al. Clinical and
and human gastrointestinal stromal tumors display immunohistochemical differentiation of gastrointestinal
similar mutations in c‐kit exon 11. BMC Cancer stromal tumors from leiomyosarcomas in dogs: 42
2010; 10: 559. cases (1990–2003). J Am Vet Assoc 2007; 230: 1329–33.