In Jackson’s case, metronomic chemotherapy
helped pave way for two years of quality life
Photos by Kate and Matt Herz and Eugene Pavlov
By Ranny Green
Going to battle with canine cancer can be a pretty scary proposition for most owners. Yet the bottom line becomes one of teamwork and trust between the owner, primary veterinarian and specialist, usually a veterinary oncologist.
Add a relatively new treatment mode into the picture and you have everyone’s attention.
That was the case with Jackson, a 10-year-old border collie mix, owned by Kate and Matt Herz, of Seattle, and a featured Animal Survivor story in June at the American College of Veterinary Internal Medicine Forum in Seattle, attended by more than 2,500 practitioners.
Jackson was diagnosed with cancer in December 2010. He had been limping for a couple of weeks, Kate Herz recalls, and was taken to the dog’s regular veterinarian for a check of his rear legs. It turned out he had partially torn anterior cruciate ligaments in both limbs and a lump was found on his anal gland during a rectal examination prior to his X-rays.
Jackson was referred to Dr. Chelsea Tripp, a Seattle veterinary oncologist, who diagnosed anal-sac adenocarcinoma, a highly invasive disease which Kate Herz researched on the internet and found the following grim descriptions: “generally does not have a positive outlook”; “uncommon and aggressive”; and “high recurrence rate.”
Tripp painted a bit more positive scenario for the couple and assured them Jackson had a shot at living with cancer for possibly more than a year, since it had been caught early.
In January 2011, Jackson underwent surgery to remove the tumor, but it was not completely resectable. At that point the veterinarian recommended chemotherapy, based on Jackson’s blood work and other considerations.
A month later the tumor has spread to his lymph nodes and the owners were faced with a harder decision on whether to go forward with a second surgery. With Tripp’s counsel, they did.
“During his recovery from the second surgery,” Kate Herz says, “Jackson gave me the look that said, ‘Please, no more surgeries.’ At this point, we made the decision to treat him with chemotherapy.”
But this wasn’t your conventional chemo regimen that produces plenty of emotional baggage.
For veterinary oncologists, all options are predicated on quality of life.
For Jackson, Tripp chose metronomic chemotherapy, also known as low-dose, continuous treatment. In conventional chemo, the idea is to find a maximum tolerated dose and treat repeatedly, trying to kill every cancer cell. The metronomic approach is not aimed at killing the cancer cells but rather depriving them of nutrients they need to grow and develop and the blood supply they require to thrive.
This results in a stabilization of tumors, inhibiting or slowing additional growth rather than causing shrinkage.
Generally, metronomic chemotherapy is well tolerated by the patient and produces few side effects, yet the dog’s condition must be monitored closely. Another positive is that it can be administered by the owners at home.
But Jackson wasn‘t the prototype case from the side-effects standpoint. He encountered problems with two chemo drugs before Tripp settled on chlorambucil and then cyclophosphamide, which he remained on daily doses for two more years.
“It’s a decision we will never regret,” emphasizes Kate Herz. “He did not have a reduced quality of life and, if anything, the last two years of his life were his best.”
His drugs were ordered through an online drug company; the monthly costs were a reasonable $48 (cyclophosphamide) and $88.50 (chlorambucil). “The company sent the package every month with a dog biscuit,” Kate Herz recalls, “so Jackson was always thrilled when his chemo supply arrived.”
The owners administered his chemo along with his drugs for mobility every morning. “He looked forward to taking his pills mostly because it either meant cheese or hotdogs,” she adds. Because they were handling a chemotherapy drug, gloves were required.
Jackson’s diet was altered a bit in his final two years – a mixture of chicken, rice, sweet potato and cottage cheese daily. His rechecks with Tripp were usually every six to eight weeks, although occasionally they were extended longer because of the treatment’s success.
About a year into his care, Jackson needed a haircut. The couple did the cut at home (due to his treatment he no longer received vaccines and it was difficult to find a groomer who would accept him without proof of updated booster inoculations). But his coat’s regrowth wasn’t normal, regenerating only on his belly and lower body, gradually producing a reverse Mohawk look, with no hair on his back but his normal bushy Afro everywhere else.
Eventually they purchased a sweater for the cold months. “We discussed it with Dr. Tripp, who told us that dogs usually are not on chemo for as long as Jackson and that it is just one of the things that can eventually occur,” explains Kate Herz.
Metronomic chemotherapy gave the couple an extra 26 quality months with Jackson. “He swam in the lake, ran in the park, he gobbled his food down happily every day and would snuggle up with us as he had every day before his diagnosis,” she says.
Tripp adds, “Jackson was a special guy. He was a poster child of handling chemotherapy.”
And Matt Herz says,” Jackson acted like a typical 10- or 11-year-old dog in his final two years, not a sick animal. Metronomic chemotherapy was a terrific option and allowed us to treat him at home, which reduced our costs and the stress on Jackson of having to make continued trips to the veterinarian.”
Jackson did not succumb to cancer, rather kidney failure Feb. 23. “In our minds he beat cancer,” says Kate Herz, “and it was Dr. Tripp and metronomic chemo that gave him the tools to do so.”
Dr. David Vail, a University of Wisconsin School of Veterinary Medicine professor of oncology and a consultant in veterinary cancer care for Seattle Veterinary Specialists in Kirkland, says, “Metronomic chemotherapy has received plenty of discussion in veterinary circles the past decade. Results have been mixed and its effectiveness is still an area of controversy.”
Vail, a speaker at the ACVIM Forum in Seattle, cites four types of cases where this treatment is primarily reserved:
(1) Cancer has spread significantly.
(2) The primary tumor is not amenable to surgery or radiation or has been declined by the caregiver.
(3) Traditional chemotherapies are unlikely to produce a positive result.
(4) The primary cancer has been effectively removed but the likelihood of future recurrence or spread is high based on the specific cancer being treated.
“There is still plenty to learn about the relative risks of metronomic-chemotherapy treatment,” Vail explains, “from the standpoint of drugs, dosages and side effects. But it does offer oncologists an option in some cases for a patient‘s quality-of-life care for an extended time. “
Another ACVIM Forum speaker, Dr. Anthony Mutsaers, a Ontario Veterinary College, University of Guelph, Ontario, Canada, oncologist, adds, “Low-dose metronomic protocols have generally been well tolerated in the short term. However, when using a metronomic-treatment strategy, clinicians must be mindful of side effects that may only occur after prolonged drug exposure.
“The most concerning side effect encountered to date has been sterile cystitis (a condition that causes bladder inflammation and associated clinical signs without any infection) with cyclophosphamide use, although the occurrence has not been reported to be higher than that observed with conventional protocols.”
But, he adds, low-dose metronomic protocols have generally been “well tolerated in the short term.”