Comorbidities and Their Role in Cancer Treatment

 

Globally, cancer is the second leading cause of death. It accounted for around 9.6 million deaths in 2018 and comorbid conditions added to lower survival outcomes for up to 30% cases. Patients with comorbid conditions need extra care and management from the care team. A comorbid condition is one of the major factors that can affect the outcome of the cancer patient; other factors include age, nutritional status and correct treatment, etc.

What is comorbidity?

A comorbidity is an adjunct chronic disease condition that coexists with the primary disease. Given that most of cancers are diagnosed beyond 50 years age-group, these comorbid conditions may be preexisting. Some examples of comorbid conditions with cancer include cardiovascular disease including, diabetes, heart failure, chronic obstructive pulmonary disease, peripheral vascular disease, cerebrovascular disease, dementia, joint problems, liver disease, kidney problems, obesity, or hypertension.

Some of these comorbid conditions share common risk factors with cancer. 

At times, comorbid conditions can have a significant impact on the treatment of cancer and patient outcomes. 

Impact of comorbidities on the choice of cancer treatment

The available treatment options may vary based on the type and severity of the comorbidity. Some oncologists may not recommend certain cancer treatments for patients with comorbid conditions due to a high risk of side effects and complications.  

For example, a chemotherapy drug may accumulate in the body of patients with compromised kidney function and can cause life-threatening toxicity. These patients may not be good candidates for standard chemotherapy and may need modification of drug doses or replacement with another drug which might affect treatment outcomes.

Impact of comorbidities on cancer treatment outcomes

The type and severity of comorbidity affect treatment outcomes. For example, a patient of chronic obstructive pulmonary disease may not be able to tolerate anesthesia required for thyroid cancer surgery, and hence would need a customized approach to cancer treatment.

The healthcare team should involve the experts from other specialties when planning cancer treatment for a patient with comorbid conditions to help improve the treatment outcomes. 

The outcome of the treatment will depend on factors like the type, severity, and the number of comorbidities involved.

Effect of comorbidities on survival

Comorbidities do have an adverse effect on cancer survival. The cancer-specific survival of a person depends on the stage of cancer, the prognosis of cancer, the severity of the comorbidities, and the impact of the treatment.

The comorbidities may affect survival due to several ways. One aspect is the direct impact of the condition on mortality. Another is that cancer patients with comorbidities receive less intensive treatment, affecting their survival. It is also possible that the patients may face increasing levels of toxicity from the treatment, decreasing the rate of cancer-specific survival. The comorbidities may also have a direct impact on cancer progression.  

Effect of comorbidities on the quality of life

The quality of life is poor for cancer patients with comorbidities. In general, the quality of life is poor for cancer patients, but when accompanied by comorbidities, it decreases further as it causes significant strain on body’s physiological functions.

Effect of cancer treatment on comorbidities outcome

It’s not only comorbidities that affect the cancer treatment outcome, but vice-versa is also possible. The cancer treatment may affect the comorbidities outcome.

Cancer therapies can increase the risk of musculoskeletal, cardiovascular, metabolic disorders, and worsen the existing comorbidities. These impacts are higher in patients with preexisting comorbid conditions as those may deteriorate further owing to treatment side effects. We need to ensure adequate attention is given to managing comorbid conditions during cancer treatment to ensure seamless treatment and avoid complications.

Strategies to address comorbidities in a cancer patient

Several challenges are faced when treating patients with comorbid conditions. We need to find a better approach to address these challenges. Both research and clinical practice strategies are required to address comorbidities.

The following strategy points may aid in providing a better outcome:

• Measuring the comorbidity: It is important to measure comorbidity more accurately in cancer patients. This will aid in understanding the relationship between comorbidity and the cancer outcome in a better way.
• Better coordination and integration of care: It is important to give care beyond cancer and take care of all the other healthcare needs of cancer patients. This can be achieved by using community-based cancer services and health information technology. Collaborating with primary care services and promoting care plans can aid in the delivery of better care.
• Focus on maintaining adequate nutrition for the patient to avoid deterioration of body functions and associated comorbid conditions.
• Prevent the occurrence of new comorbid conditions: It is important to prevent the occurrence of a new comorbid condition during, or after, the cancer treatment. If any new comorbid condition occurs, it may negatively affect the treatment outcome and the cancer survival outcome of the patient.
• Further research: It is essential to evaluate the mechanisms and epidemiology of comorbidity. We also need to evaluate the models of care delivery and the impact of it. 
• Improving the research practices: It is recommended to involve people with comorbidities in clinical trials.

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