VOLUME 8 ISSUE 1 • 2019 WINTER EDITION

ANAL SAC ADENOCARCINOMA Suzanne Rau, DVM, DACVIM (Oncology)

Apocrine gland anal sac adenocarcinomas direct extension of tumor from the (AGASACA) comprise about 17% sublumbar lymph nodes to the lumbar percent of perianal malignancies, vertebrae can occur. and 2% of all skin and subcutaneous tumors. The average age at diagnosis TREATMENT is nine to eleven years. Treatment for this disease involves both local control of the primary mass itself, DIAGNOSIS AND STAGING as well as controlling tumor . Some dogs with AGASACA present with signs related to the mass itself, SURGERY such as a swelling in the perianal region, Surgery to remove the primary mass a mass palpated on routine rectal in the anal region and/or removal of exam, scooting, or straining to defecate. enlarged sublumbar lymph nodes Other dogs may present for signs within the abdomen is often the first step. indirectly related to the mass if the Ideally these tumors should be removed tumor is causing hypercalcemia, with wide margins, however, given Dr. Suzanne Rau which is reported to occur in about their close proximity to the rectum and 25% of dogs with AGASACA. These important neurovascular structures, hypercalcemic dogs may be polyuric resection is often marginal. and polydypsic. aortic bifurcation. However, they are Risk of incontinence is low and typically usually well encapsulated and can be The reported rate of metastasis at the transient with unilateral anal sacculectomy, successfully removed without major time of diagnosis ranges from 50-80%. and only slightly increased for bilateral complications. Therefore, prior to surgery and other anal sacculectomy; bilateral anal sac therapies, staging with three view chest tumors have been reported in x-rays and an abdominal ultrasound approximately 10% of cases. Masses are recommended. The sublumbar that are still contained within the anal Definitive Radiation lymph nodes are one of the most gland are generally easier to remove In cases where some cancer cells may common sites for metastasis (Figure than those that have ruptured out of have been left behind after surgery, 1). This lymph center includes the the capsule and started invading the regrowth of the primary tumor could medial iliac, hypogastric, and sacral muscle of the anal sphincter. occur in the future. Definitive radiation lymph nodes and is located within the Removal of metastatic lymph nodes therapy may be recommended caudal abdomen and pelvis. More has been shown to increase survival post-operatively in patients. This is common distant metastatic sites time in many cases. Removal can radiation treatment given in an attempt include the spleen, liver, and . be challenging due to their caudal to eliminate any residual disease both Rarely, regional bone metastasis or location within the abdomen at the at the peri-anal site and the draining FIGURE 1. Lateral abdominal radiographs showing an enlarged sublumbar causing deviation of the colon ventrally.

abdominal lymph node bed. The intent lungs. More common of definitive radiation is long-term drugs used to treat AGASACA include tumor control, and typically consists REMOVAL OF METASTATIC carboplatin and mitoxantrone. Protocols of daily treatments (Monday through LYMPH NODES HAS BEEN may vary, but often include 4-6 Friday) of a small dose of radiation SHOWN TO INCREASE SURVIVAL treatments given every three weeks. for 3-4 weeks. Dogs are anesthetized TIME IN MANY CASES. Possible side effects of chemotherapy for a short period of time during the include vomiting, diarrhea, or treatments. inappetence that can occur in a 3-5 Side effects include a radiation burn to day window after chemotherapy the sensitive skin at the peri-anal site, difference in dose administration, it is administration. Suppression of the bone as well as diarrhea due to radiation of much less likely to cause acute adverse marrow can also occur between one the sublumbar lymph node bed, which side effects in patients. This type of and three weeks after treatment lies adjacent to the colon. Although the treatment may be given once a week depending on the drug given. Rarely, side effects can be severe, they for 4-6 treatments, or daily Monday dogs have side effects that are severe typically heal within one month after through Friday for one week. In a small enough to warrant hospitalization; this finishing therapy. Some dogs, however, retrospective study, about 50% of happens in about 5-10% of patients. may experience long term diarrhea or dogs experienced shrinkage of their Chest x-rays and abdominal ultrasounds straining when defecating. anal sac masses or lymph nodes, while are usually repeated for monitoring nearly 90% had at least stabilization during therapy. PALLIATIVE RADIATION of their disease. The duration of these responses was about six months. PALLADIA An option for tumors that are not amenable to surgical removal, or CHEMOTHERAPY A newer option for the treatment is an start to recur in the future is a different oral medication called Palladia. This form of radiation therapy called palliative Chemotherapy may also be recommended is a drug that was originally approved radiation. This type of radiation similarly post-operatively, as these tumors often for treatment of mast cell tumors, targets the local mass and draining metastasize to other areas of the body, though has exhibited responses in lymph nodes. However, due to the including the local lymph node and other tumor types as well, including AGASACA. It is reported to have 9 months compared to about 19 anti-tumor activity as well as act as an months for dogs with smaller tumors. antiangiogenic drug. Side effects of Patients with an elevated calcium SPECIALIZED Palladia are primarily gastro-intestinal, levels had median survival times of 8.5 though immune suppression can also months compared to about 19 months SERVICES be seen. While a pet is on Palladia, for patients with normal calcium levels. we recommend periodic monitoring of BEHAVIOR Surgical intervention has repeatedly Jacqueline Wilhelmy, MS, VMD, bloodwork to evaluate for any adverse been shown to play an important DACVB, CCBC-KA effects. This drug is given continuously factor in prognosis. Dogs treated with on an every other day or Monday, CARDIOLOGY surgery to remove their tumors have Wednesday, Friday basis until it is Marc Kraus, DVM, DACVIM (Cardiology) a more favorable outcome than dogs no longer effective. This treatment is Michael Miller, MS, VMD, ABVP with tumors that were not, or could not often reserved for tumors that cannot Risa Roland, DVM, DACVIM (Cardiology) be removed. Even when lymph nodes be removed, recur, or have started to are affected, surgery to remove these DENTISTRY spread elsewhere since it needs to lymph nodes along with the primary Corinne Durand, DVM be given continuously for as long as it tumor can result in a median survival remains effective. DERMATOLOGY time of over two years. If a tumor is Karen B. Farver, DVM, DACVD There are several retrospective studies found to recur locally or metastasize EMERGENCY AND CRITICAL CARE evaluating the use of Palladia for the to lymph nodes in the future, a second James Buckman, PhD, VMD treatment of AGASACA. In one report, surgery can result in a median of 283 Allison Buysse, VMD 25% of dogs experienced shrinkage of days of additional survival time. Jason Chamberlin, VMD their disease, while 88% had at least Cierra French, DVM Dogs treated most aggressively with stabilization of their cancers. In a Robert Gaunt, VMD a combination of surgery, radiation second report, 62% of dogs experienced Jill Kalman, VMD therapy, and chemotherapy had a shrinkage of their disease, while 75% Daniel Lantz, VMD median survival time of over two years Jennifer McGough, VMD has at least tumor stabilization. In this in one report. Rachel Morgan, DVM study, the median progression free (Practice limited to Emergency & Critical Care) interval was 328 days. Marisa Suvannavejh, VMD CONCLUSIONS Katrina Tumielewicz, DVM SUPPORTIVE THERAPIES Although AGASACAs raise the (Practice limited to Emergency & Critical Care) concern for both the control of the Medications such as stools softeners INTERNAL MEDICINE local tumor, as well as the control of and anti-inflammatories can also be John V. DeBiasio, DVM, DACVIM distant cancer metastasis, there are James F. Dougherty, MS, VMD added for patients who have difficulty many therapy options available. Tabitha A. Hutton, DVM, MTR, DACVIM (SAIM) defecating due to the presence of Leslie A. Kuczynski, VMD, DACVIM the primary mass or enlarged lymph The prognosis can be favorable with nodes in the region. This can offer multimodality treatments. However, INTERVENTIONAL RADIOLOGY relief for many patients by allowing even when an owner elects against Risa Roland, DVM, DACVIM (Cardiology) them to defecate more easily. more aggressive treatment modalities MINIMALLY INVASIVE SURGERY such as surgery and radiation therapy, John V. DeBiasio, DVM, DACVIM Symptoms of hypercalcemia can be medical therapies can often help Leslie A. Kuczynski, VMD, DACVIM controlled with fluid therapy and to control a tumor and keep a dog prednisone, or calcium lowering drugs NEUROLOGY comfortable for a period of time. like . Melissa Logan, PhD, DVM, DACVIM (Neurology)

PROGNOSIS ONCOLOGY The overall median survival time for Lillie Davis, DVM, DACVIM (Oncology) MVA IS NOW USING IDEXX’S Kendra Hearon, VMD, DACVS-SA AGASACA is about 18 months with RVETLINK SOFTWARE TO ACVS Fellow, Surgical Oncology various forms of treatment. However, AUTOMATICALLY SEND Suzanne Rau, DVM, DACVIM (Oncology) many factors including characteristics ADMIT AND DISCHARGE OPHTHALMOLOGY of the tumor, results of staging tests, NOTIFICATIONS THROUGH Amanda Corr, VMD, DACVO and therapy options chosen by the CORNERSTONE! owner can all impact prognosis. RADIOLOGY Please contact Heather Moyer Robert McLear, VMD, DACVR Factors including a larger tumor size or Stacey Connell if you have Lisa Suslak, VMD, DACVR at the time of removal (>10cm2), the any questions or concerns presence of metastasis, and about rVetLink, we’re here SURGERY hypercalcemia on blood work have to help by emailing us at Kendra Hearon, VMD, DACVS-SA been associated with a more guarded [email protected] or A. Jon Nannos, DVM Jacqui Niles, BVETMED, SAS, DACVS 2 calling 610-666-1050. prognosis. Dogs with tumors >10cm Catherine Popovitch, DVM, DACVS, DECVS had median survival times of about Timothy M. Schwab, VMD, DACVS-SA Rebecca Wolf, VMD, DACVS-SA ONCOLOGY AT MVA

At MVA, we are driven by compassion and healing. We know how hard it can be for a client to learn that their beloved pet has cancer, and we strive to help them along every step of the journey.

Medically, we are committed to providing advanced therapies through a multidisciplinary approach. This can include surgery, chemotherapy, or radiation therapy, with an emphasis on pain management, nutrition, and complementary therapies.

PET LOSS SUPPORT GROUP Suzanne Rau Lillie Davis At MVA we understand the depth DVM, DACVIM DVM, DACVIM of loss one experiences when a (Oncology) (Oncology) beloved four-legged family member has passed. For that reason, we provide a Pet Loss Support Group to help grieving owners in need. Our group is designed to provide grieving pet parents with a safe, confidential environment to share their feelings with others who have experienced pet loss. Jacqui Niles Kendra Hearon BVETMED, VMD, DACVS-SA, ACVS The group is operated by SAS, DACVS Fellow, Surgical Oncology professionals who have experience with pet loss. A board certified psychiatrist consults with us regarding the implementation of the group, however, our group leaders are not mental health care professionals. Clients experiencing difficulty coping are urged to seek help from a mental healthcare professional. We Corinne Durand can provide you with the names DVM of health care professionals if needed. Our Pet Loss Support Group meets on a varying schedule. For dates please call the MEET OUR TEAM WITH A LUNCH & LEARN AT YOUR PRACTICE! hospital at 610.666.1050 or To schedule, please email MVA Hospital Administrator visit metro-vet.com/petloss Stacey Connell at [email protected].

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