Bullmastiff rectal tumor

Surgery is not always a good option.

Helios, a seven-year-old bullmastiff, was diagnosed with rectal cancer. His owners opted out of treatment, allowing Helios to spend his days without enduring painful procedures. - Wiki Commons

When I first met Helios, he was 11 weeks old and already weighed 30 pounds. Not surprising for a bullmastiff puppy. (Yes, one word … no space between bull and mastiff.) According to the American Kennel Club, the average male bullmastiff weighs 120 pounds. That’s a lot of dog. Originally created by crossing mastiffs with bulldogs, this sturdy breed was developed in 19th century England specifically to deal with poachers on large estates. Gamekeepers found their traditional mastiffs too slow and not aggressive enough to catch trespassers. Bulldogs, on the other hand, were a bit too ferocious, and too small, to do the job. By crossing the two, gamekeepers made a new breed that could wait silently, run fast, attack on command, and pin and hold their targets without mauling them. Because most of this activity occurred after dark, bullmastiffs were also known as “night dogs.”

Bullmastiffs can be wonderful family pets. They don’t bark much. (Being quiet is useful, so poachers don’t hear you lying in wait.) They have been described as loyal, docile, fearless, confident, and sweet-natured. Despite their imposing size and moderately energetic natures, they don’t require huge amounts of exercise. Although somewhat pug-faced, they are less prone to the respiratory ailments that plague bulldogs, shih tzus, and the like. Their short, sleek fur needs minimal grooming. Many have light fawn-color, coats but I love the dark brindle coat color, which was originally thought most desirable, as it provided natural camouflage in the nighttime woods.

Helios was a classic brindle. In my office, he always exhibited a mellow disposition. Despite an isolated transgression in his youth when he bit someone, I loved this big guy, and felt perfectly at ease with him, so when his owners forgot the stool sample for his annual physical exam this September, I didn’t hesitate to don a glove and just go get it, if you get my drift. But when I withdrew my finger, it was tinged with bloody diarrhea. His owners thought he might have eaten some junk during a beach walk, so I prescribed antidiarrheal medication and sent them home. Soon after, we also discovered his housemate dog had intestinal parasites called whipworms, which are easily passed between dogs by “fecal-oral” contamination. Both dogs were dewormed, and the owners instructed to clean all feces from the yard to prevent reinfection.

Two months later, Helios returned because he was having difficulty defecating. He seemed his usual happy self, but had lost 10 pounds. Again, I grabbed a glove. Again, I found loose stool, though no blood this time. Repeating the parasite test, we ruled out recurrent whipworms. “Probably more snacking at the beach,” I said, prescribing the same medication that had worked so well previously. But this time it didn’t work. Helios continued to strain.

Straining to poop can be confusing. It can indicate constipation, but also can occur with diarrhea because intestinal cramps can create the urge to go, even when there is nothing left inside to squeeze out. “Time for radiographs,” I announced. X-rays revealed lots of firm feces throughout the bowel, but stopping abruptly several inches before the pelvis. Why wasn’t it moving down and out as it should? There was no clear explanation on the film.

“Sorry, old boy,” I sighed, donning another glove. Might there be an obstruction I could feel rectally, if I tried harder? No. Nothing. I called my assistant. “Can you get him to stand up and put his front paws on your shoulders?” I asked. Maybe being “upright” would shift things down toward my finger. Helios complied, standing almost as tall as my helper. I sat on the floor behind him, and continued my exam. Sure enough, with the change in position, I could just touch something with the very tippy-tip of my finger. From the small portion I could reach, it seemed to be an annular mass, like a fleshy doughnut in the rectum, occluding the passageway.

Rectal tumors are relatively uncommon in dogs. They can be benign or malignant. Symptoms are primarily associated with intestinal obstruction and may include straining, bloody stool, rectal bleeding, vomiting, diarrhea, and weight loss. Definitive diagnosis requires biopsy. For Helios, referral for endoscopy was the next logical step. By anesthetizing him, getting a good look with a scope, and taking a biopsy, a specialist could get more information, including treatment options and prognosis.

But realistically, the odds weren’t in Helios’ favor. Statistically, this growth was most likely adenocarcinoma, a type of cancer that, when affecting the bowel, often grows as a “circumferential infiltrate” … just like what I felt with my fingertip. It frequently spreads to local lymph nodes and liver. Surgery is usually the treatment of choice, but can be very difficult, with high risk of postoperative complications, such as permanent fecal incontinence.

Sometimes it can be necessary to break the pelvic bones in order to get better surgical access. Even with surgery, median survival time is under a year. If the cancer has already metastasized, it’s a mere three months. Chemotherapy rarely helps. Other canine rectal tumors may have better survival times, but overall, they are bad news. Helios’ owners had tough decisions to make. Despite lacking definitive proof, I was pretty sure this was cancer. Should they proceed with endoscopy and biopsy? Pursue surgery? Considering the odds, was there an acceptable “pain to prognosis” ratio? And what about the cost?

Helios and family headed south for the winter. There, a specialist confirmed the presence of the mass and concurred with my presumptive diagnosis. At almost seven years of age, Helios is considered an old bullmastiff, the average life expectancy for his breed being eight to ten years. He is currently maintaining a reasonable day-to-day quality of life on a regimen of laxatives, anti-inflammatory medication, antibiotics, and antacids. But his owners have wisely opted to let him live what time he has left without further painful or invasive procedures. It’s snowing here today. I hope Helios is somewhere basking contentedly in the Florida sun.