lymphoma prognosis | Prognosis of canine digestive lymphomas

Prognosis of canine digestive lymphomas

Introduction

Digestive lymphomas are infrequent in the canine species and 5 to 7 per cent of Canine Lymphoma. It is most often a primitive extra-nodale form in the digestive tract rather than secondary digestive impairment during ganglion form multicenter. The equivalent of the feline low-grade Lymphoma, Lymphocytic form is very rare in dogs, all forms are indeed much more frequent. The described locations are by order descending (IG) small intestine, stomach and colon. Attacks joint IG and stomach or GI and colon were observed. In its location in the GI, lymphoma is most often of immunophenotype T (from 63 to 100% of cases according to studies). The clinical signs are very specific: fatigue, weight loss, change in appetite, vomiting and diarrhea. Abdominal palpation may reveal the presence of an abdominal mass (tumor focal or adenomegaly) either a thickening of the intestines. The presence of ascites is also described. Finally, digestive bleeding are also possible. The most common biological change is the hypoalbuminemia. The prognosis of stomach lymphoma is most often very derogatory.  However a study described the excellent prognosis of rectal Lymphoma of immunophenotype B (Van den Steen 2012). Here, we describe the different prognostic factors known in the literature and the expected results of chemotherapy during digestive Canine Lymphoma (Frank 2007, Rassnick 2009).

A short survival

In the first series described (Couto 1989), all dogs with digestive Lymphoma were dead or euthanized within a period of 3 to 14 weeks (98 days) after the initial diagnosis. A more recent study (Frank 2007) confirmed this pejorative prognosis, even in combination chemotherapy, with a median survival for the 30 cases described in 13 days! In this same article, the longest survival seen in locations other than the large intestine was 81 days. However colorectal tumors were associated with longer survival. A combination of more intense chemotherapy Protocol, including 7 molecules of chemotherapy (Rassnick 2009) led to the following results: a response rate clinical 56% (50% complete remission) and 6% of partial remission with a median remission of 86 days for complete answers and a median survival of 77 days for the total population.

Prognostic factors

The following factors have been described as prognostic in lymphomas of the IG (Frank 2007, Rassnick 2009), with sometimes very important changes in the observed survival:

The immunophenotype: median survival (SM) of 3 weeks during immunophenotype T against 3 months during immunophenotype B (other than rectal damage).

The presence or not of diarrhea at the time of the initial diagnosis: SM 70 days versus 700 days.

Presence of a response to chemotherapy: SM of 117 days for answering machines compared to 10 days for the ICI.

The location of the lymphoma: SM 13 and 77 days at achievement of the IG versus over 4.5 years for rectal lymphoma. The survival of colic forms is also better in different studies.

An entity to share: B rectal Lymphoma

The prognosis of Canine Lymphoma depends on many factors including the morphological subtype, the grade, the immunophenotype, stage and location. Some entities are so well-defined, as in human cancer, by these criteria and associated with a specific prognosis. An example of very good prognosis entity makes the B-cell lymphoma, low-grade, splenic marginal zone said. Its extension is in the vast majority of negative cases at time of diagnosis and survival after Splenectomy alone, without chemotherapy adjuvant, is excellent (40 months). Another example is that of the B-cell lymphoma rectal of immunophenotype. This lymphoma is also associated with a better prognosis (Van Den Steen 2012) under chemotherapy with a described average survival, greater than 4.5 years. All cases of this study were of immunophenotype B (unlike what can be observed at achievement of the IG) and negative balance of extension. The implementation of chemotherapy was a major prognostic factor for this population with a median survival for dogs not subject of chemotherapy to just 28 days against more than 2352 days for those receiving. According to this study, excision of the tumor lesion does not seem necessary. Chemotherapy may also not be too intense for this entity since 100% of the dogs experienced a complete response after a single injection of chemotherapy and received either a Protocol at low doses or a short Protocol (type CHOP with a maintenance of only 6 weeks).

Remember

The immunophenotype lymphomas T of the IG are of very poor prognosis with median survivals varying from 1 to 3 months even under multidrug.

Factors associated with a better prognosis are the immunophenotype B, the absence of diarrhea at the time of diagnosis and response to chemotherapy.

Rectal B lymphomas are of excellent prognosis undergoing chemotherapy (over 4.5 years of survival); surgery is not necessary for their operation and chemotherapy implementation can be very intense.

Example: dog American Staffordshire, male, 11 years old, with a colonic Lymphoma manifest clinically by a hematochezia, with a secondary extension to colic lymph nodes and spleen (stage 4).