Surgery has played a fundamental role in cancer treatment for thousands of years. Until the development of chemotherapy and radiotherapy, surgery was often the only remedy available for many cancers (Markham et al., 2020). Until 150 years ago, when antiseptic methods and anaesthesia were introduced, surgery was largely limited to small and localised cancers and the prognosis was generally considered poor.
Nowadays, surgical oncology is a mature and disciplined field. Surgery remains a critical modality for many cancers, providing improved survival times, reduced pain and improved quality of life. Surgery plays a central role in the treatment of solid tumours in human cancer patients and is a fundamental method for the treatment of primary tumours at both a local and a regional level (Shams et al., 2023).
Large, radical surgeries would not be possible if it were not for the huge advancement in other medical services, such as anaesthesia, analgesia, transfusion medicine and critical care
The surgical management of cancer requires a precise and considered strategy. It is also recognised that the success of surgery in cancer patients will only be as good as the supportive team. Large, radical surgeries would not be possible if it were not for the huge advancement in other medical services, such as anaesthesia, analgesia, transfusion medicine and critical care. For these reasons, it is important that the entire veterinary team is on board with the surgical procedure and suitably trained to deliver a high standard of care during both the peri- and post-operative periods (Withrow, 1998).
Advancements in veterinary surgical oncology: an overview
Historically, surgical oncology was driven by a dogma to eliminate all possible traces of the cancer with limited regard for patient morbidity and overall outcome. Today, with a better understanding of cancer biology and better documentation of survival times and local recurrence rates, surgeons are able to be more targeted in their surgical strategy.
The use of cytology and pathology prior to surgical intervention enables the surgeon to understand what type of tumour is present, which allows them to determine the surgical dose required. A benign tumour such as a lipoma may only require low-dose surgery, whereas tumours with a high rate of local recurrence, such as a mast cell tumour or soft tissue sarcoma, will need a wider margin with incorporation of tissue barriers to limit the risk of residual tumour being left in the patient. For invasive and highly aggressive tumours, such as an osteosarcoma or high-grade soft tissue sarcoma, a more radical surgical approach is required to allow an entire anatomical compartment to be removed around the tumour, which may require amputation of a body part or limb.
Recent advances in medical imaging have allowed the surgical team to assess tumour location and vascular structure to formulate a more accurate surgical plan. Computed tomography (CT) or magnetic resonance imaging (MRI) also allows for better staging. Increasingly, advanced techniques such as sentinel lymph node mapping techniques are being used in veterinary medicine. Through this, the surgeon is able to remove secondary disease, such as draining lymph nodes, at the time of initial surgery, thus leading to better outcomes.
Surgery and adjuvant treatments
Although there have been major advancements in large resections and reconstructive surgery, the oncology field has also steered towards using multiple oncology interventions rather than a single modality. This is due to the progression of adjuvant treatments like chemotherapy and radiotherapy, as well as the result of surgical training. Combining these treatment strategies has helped reduce the morbidity of surgery while providing similar (or better) patient outcomes.
For example, chemotherapy can be given prior to surgery to help shrink a chemotherapy-responsive tumour (eg thymoma, mast cell tumour). This strategy – called neo-adjuvant chemotherapy – has been shown to enable greater success with surgical excision alone and can sometimes allow a previously inoperable lesion to become operable.
Radiotherapy may also be used alongside surgery – either in a pre-surgical or post-surgical setting. In human cancer patients, the incorporation of radiotherapy has allowed surgical margins to become more constrained without compromising the successful local control of the tumour.
Ethics and veterinary surgical oncology
Although radical surgery is known to give better outcomes and the potential of a surgical cure, human cancer patients often battle with the daunting prospect of life-altering surgery for a better survival time (Shams et al., 2023). In veterinary oncology, we rely on the owner and veterinary team’s acceptance of cosmetic and functional defects in exchange for a longer remission, allowing us to perform these radical surgeries.
Each veterinary professional’s moral compass will sit at a unique point and will often depend on experience, training and exposure to oncology cases
The ethical concept in animal cancer patients is often a sensitive and difficult discussion to broach in veterinary medicine. Each veterinary professional’s moral compass will sit at a unique point and will often depend on experience, training and exposure to oncology cases. In a referral hospital setting, surgical doses tend to be higher due to extensive training and nursing expertise. Radical surgery will often be performed by surgeons specifically trained or training in oncology to ensure the correct technique is used to gain the best outcome for the patient.
When considering radical surgery in veterinary practice, there are a number of different aspects that should be considered. Although the surgery is often technically possible, each patient should be assessed individually, and an ethical discussion should take place to confirm that the planned surgery is appropriate for the patient. For example, it is known that aggressive mastectomy surgery in human and canine patients does not necessarily provide improved survival times when compared to more conservative surgeries, but in feline patients, a uniformly aggressive approach is considered important due to the higher incidence of multifocal disease in this species (Withrow, 1998).
Although the surgery is often technically possible, each patient should be assessed individually, and an ethical discussion should take place to confirm that the planned surgery is appropriate for the patient
Another example is total cystectomy in a canine patient with urothelial cell carcinoma. While this surgery is technically achievable, it is associated with a high rate of morbidity due to permanent incontinence and progression of metastatic disease. Therefore, current survival times may be no different to patients receiving more palliative treatment options.
Just because we can perform a surgery, does it mean we should?
The surgical team should consider the patient, family and veterinary team when contemplating a radical surgery. Although surgical intervention is physically possible, each patient should be assessed on an individual basis to decide if the proposed surgery is appropriate for them. Will the patient be able to perform the normal behaviours and physical activities that are important to them?
For example, a glossectomy may be a treatment option for a feline patient with a squamous cell carcinoma invading the tongue; however, this is often an ethical dilemma as the patient will be unable to eat or groom themselves, which, in turn, reduces their quality of life. Removing part of the pinna or face of a patient may alter their ability to express normal facial expressions, making communication with other animals difficult. While one patient may be suitable for a limb amputation, an overweight patient or those with osteoarthritis may struggle to adapt to life on three legs.
The impact of comorbidities
As many oncology patients are geriatric, they often present with comorbidities that pose potential intraoperative risk factors, such as hypotension, blood loss or cardiac disease, negatively affecting anaesthesia. The recovery process should not be overlooked, and the patient’s ability to cope with the immediate post-operative process and long-term recovery should be discussed.
For example, following a limb amputation, the patient will need support while learning to ambulate on three limbs – a patient’s nervous disposition could negatively affect the ability to adequately nurse the patient on recovery. It is known that stress can prolong wound healing time. Radical facial surgeries, on the other hand, pose different challenges for the patient in the form of nutrition. It is known that canine patients often learn to eat following a mandibulectomy, but feline patients can take two to four months to adapt, with 12 percent never eating voluntarily again (Northrup et al., 2006).
A big commitment – finance and other concerns
The patient’s family should be considered in regard to the potential financial and time commitment necessary following radical oncology surgery. The financial implications of a radical surgery are often extensive, with further financial commitments should a complication occur on recovery. Potential complications should be discussed prior to surgery to ensure the owner understands the risks post-operatively. For example, mandibulectomy/maxillectomy surgery can pose a risk of incisional dehiscence, oronasal fistula formation, epistaxis and mandibular drift/malocclusion, which all require additional treatment.
The veterinary surgeon should educate the owner before surgery so they can make an informed decision based on what is best for them and their pet
The family should be educated on what post-operative care may look like at home. Home adaptations will be needed following amputation, such as anti-slip flooring, ramps into the car or house, and sling-walks to support them in the early stages of recovery. Facial surgeries may require nutritional support, such as tube feeding or regular sedation for oral examination. The veterinary surgeon should, therefore, educate the owner before surgery so they can make an informed decision based on what is best for them and their pet.
A team approach – consider the morals, ethics and concerns of all parties
The veterinary team should be adequately trained to support these patients peri- and post-operatively. The nursing team is paramount to the successful recovery of radical surgeries and should, therefore, feel confident in implementing nursing care plans and using advanced nursing devices.
Adequate staff, equipment and pharmaceuticals should be checked before surgical planning, to ensure the team is prepared for every eventuality. It may also be beneficial to prepare the staff for what to expect cosmetically following radical facial surgeries, such as nosectomies and mandibulectomies, so they can provide the highest standard of care.
The nursing team is paramount to the successful recovery of radical surgeries and should, therefore, feel confident in implementing nursing care plans and using advanced nursing devices
Veterinary staff may struggle with the concept of radical surgeries due to the belief it could reduce the patient’s ability to perform species-specific behaviour (such as a ball-driven dog being unable to play with a ball or a feline patient unable to groom themselves following a mandibulectomy). Success stories or photos of patients enjoying life following surgery may help staff understand that patients can live happy lives following radical surgical intervention.
It is important to respect and listen to the veterinary team’s concerns regarding patient care. In a 2012 survey given to UK-based veterinarians, the most stressful ethical dilemma was reported to be when a client wishes to pursue treatment despite poor animal welfare (Batchelor and McKeegan, 2012). As a result, an ethics committee was established in the author’s hospital (AURA Veterinary) to help handle these concerns. The committee is composed of veterinarians, nurses, patient care assistants and non-medical lay staff who are able to be called together at short notice. This committee provides a formal process by which any member of staff can raise any concerns they may have about a planned surgery or the welfare of the patient receiving cancer treatment.
Providing a safe space for an open discussion may help put the team’s mind at rest that the treatment strategy is appropriate or, alternatively, come to a decision regarding the best way forward
All staff are invited into a safe place to be honest and ask appropriate questions. In some instances, the patient’s family may also be involved in the ethical discussion if patient welfare is a concern. This mechanism allows the veterinary team responsible for the patient to fully share the treatment plan and expectations. Providing a safe space for an open discussion may help put the team’s mind at rest that the treatment strategy is appropriate or, alternatively, come to a decision regarding the best way forward, which may include euthanasia or a decision not to proceed with a planned surgery. Ultimately, the main aim should always be to maintain quality of life and alleviate suffering.
Summary
Akin to human surgery, veterinary surgery continues to push boundaries and advance. Further advancements in radiotherapy, chemotherapy, immunotherapy and minimally invasive techniques enable us to provide patient-centred care for our veterinary oncology patients. Each patient should be considered as an individual, and treatment plans adapted accordingly. Although radical surgery plays a role in cancer treatment and gaining longer survival times, we should always aim to reduce symptoms and maintain a good quality of life.
