Background
A significant proportion of patients with cancer undergo therapy comprising chemotherapy, radiotherapy and immunotherapy (alone or in combination). These treatment modalities target rapidly dividing cancerous cells, but may also affect non-malignant cells and thereby induce toxicity, leading to serious adverse effects1-4 (see figure 1 below). A careful evaluation, together with the patient’s comorbidities and nutritional status, is therefore essential prior to prehabilitation and surgery.
The following section is intended to serve as a guide to the adverse effects of chemotherapy, immunotherapy and radiotherapy, in order to direct evaluation prior to undergoing prehabilitation and surgery.
Figure 1: Potential toxic effects of cancer therapies
Screening
As part of preoperative assessment, the health practitioner should take a focused history of cancer management. A detailed history includes the precise chemo-/immunotherapy or radiotherapy regime used and any specific toxic effects suffered by the patient.
See Appendix 1 below for a listing of commonly used cancer therapies and their effects on organ systems.
Assessment
Clinical features of toxicity which may alert the clinician to more serious systemic complications include shortness of breath, palpitations, chest pains and fever.
A thorough physical examination should include an accurate evaluation of the following:
- Cardiopulmonary status
- ECG
- Pulse
- Baseline SpO2
- Blood pressure
- Laboratory tests.
These may reveal clinical features of adverse effects that require further investigation.
In some patients undergoing therapy associated with common systemic or organ-specific toxicities, further investigations may be needed to inform preoperative assessment and prehabilitation choices5,6,7, such as:
- Cardiopulmonary imaging
- Pulmonary function testing
- Echocardiography.
It may be necessary to delay surgery until critical organ dysfunction is recovered and strategies for prehabilitation may be limited8-13.
Intervention
If there is evidence of chemotherapy, immunotherapy or radiotherapy-related toxicity, physician clearance is essential prior to undergoing prehabilitation. Specialist referral and intervention is dependent on both the organ system affected and the severity of toxicity8.
Safety and efficacy of prehabilitation
Prehabilitation strategies have been successfully employed in the onco-surgical cohort with potential towards reducing mortality and morbidity. Furthermore, there has been an association with reduced length of hospital stay and consequent reduction in healthcare-related costs8-12. There is emerging evidence regarding the safety and efficacy profiles of exercise prehabilitation programs in patients limited by cardiac and respiratory disease. Prehabilitation programs in patients with moderate to severe cardiac disease awaiting cardiac surgery, including transplant surgery, has been shown to reduce post-operative complications and improve quality of life. The same holds true in patients with moderate to severe lung disease 9,10,11,14.
Prehabilitation programs should be personalised according to patient and oncological factors8, 12, 13, 15, 16. In patients with organ-specific cancer therapy related toxicity, particularly cardiac and respiratory toxicity, it is important to gain specialist approval prior to beginning an exercise programme. It is recommended that these patients have supervised regimes, which offers a margin of safety to intervene in case of adverse effects related to underlying pathological factors that may be associated with cancer therapy13-16.
Despite the benefit of pre-operative exercise programmes in the onco-surgical cohort, there are a few contraindications in which the risk of a potentially serious adverse event outweighs the benefit. These include patients with unstable angina or acute coronary syndromes, recent malignant arrythmias without device implantation or uncontrolled arrythmias, unmanaged high-grade heart block, acute heart failure, severe obstructive valve lesion, hypertrophic obstructive cardiomyopathy, aortic aneurysm greater than 5cm, untreated venous thrombo-embolic disease, severe pulmonary hypertension and untreated symptomatic secretory Neuroendocrine Tumours (NETs)8,9,14 (for more detail see Exercise safety). In these cases, a specialist prehabilitation clinician must have a risk-benefit review in conjunction with the specialist physician, exercise therapy must be supervised, and patients counselled about potential adverse effects.