When the cancer goes away, the symptoms may not: New research investigates survivors’ ‘symptom burden’
New Northeastern University research studies how the lingering symptoms experienced by cancer survivors often appear clustered together, providing a clue toward increasing survivors’ quality of life.
A declaration of remission doesn’t mean a cancer patient’s illness is fully gone. Many cancer survivors face lingering symptoms that lead to both physical discomfort and mental strain.
Even though there are some commonalities, the symptoms themselves are highly variable between individuals and difficult to predict, says Marilyn Hammer, professor of nursing at Northeastern University.
Hammer is the principal investigator of new research that explored which symptoms cancer survivors experience, how often they experience them, how severe those conditions are, if there are trends in how they appear and which symptoms appear in clusters with other symptoms.
Though nurses have been performing symptom studies for decades, the presentation between individuals is so variable that understanding how the symptoms interrelate has been a massive challenge, Hammer says.
Hammer’s work focuses on precision medicine, where individual differences in people’s genes, environments and other lifestyles help guide individualized treatment. Her work on symptom clusters is part of the effort to continue creating “tailored interventions” for those with cancer, she says.
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“Symptoms do not occur in isolation,” she continues. A better understanding of how symptoms cluster together may also help illuminate the shared, underlying mechanisms that cause them, she says.
To better understand these patterns, Hammer and her team surveyed more than 1,100 cancer survivors who reported 44 unique symptoms overall. The team looked at how the symptoms manifested, how often and where they occurred, how severe the symptoms were and how much the patients were bothered by those symptoms. The symptoms included physical and mental effects and ranged from hair loss to depression.
Rachel Pozzar, an associate professor of nursing at Northeastern who was also involved with the study, says that even though most of the survey respondents, on average, had been diagnosed eight years before the study took place, they reported an average of 10 ongoing symptoms, which varied from patient to patient.
The researchers were able to classify those symptoms into six clusters based on some commonalities, including whether they were mental health-related, a direct result of the cancer and associated treatment and whether the symptoms had to do with pain.
The team also calculated the patients’ “symptom burden.” “The more strain the cancer survivors said they were under because of their symptoms, the greater the symptom burden, which helped researchers look into the risk factors that might increase that strain.
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The most common symptoms — including pain, fatigue, difficulty sleeping and depression — were not the symptoms that caused the most distress, like hair loss. This realization, Hammer says, “helps us to focus on symptoms that cause the greatest decline in physical function and associated quality of life,” regardless of distress level or frequency.
The researchers then calculated which characteristics seemed to correlate with higher symptom burden. Women seemed to have a greater symptom burden, as did those who had other medical conditions in addition to a history of cancer. Those who had received more cancer treatments than the other respondents, or those who had metastatic cancer, also seemed more likely to have high symptom burden, according to the paper.
With continued analysis, Hammer hopes to find what she calls a “sentinel symptom,” something that might herald the appearance of other symptoms in the same cluster. She is already working on research looking at the prevalence of other medical diagnoses in cancer survivors and those conditions’ impact on lingering symptom clusters.
Pozzar says that the next step is to develop new methods to help survivors “manage symptom clusters rather than individual symptoms” and developing strategies to identify those “who are at risk for persistent symptoms.”
Ultimately, Hammer sees this research as vital to increasing cancer survivors’ quality of life. “If we can solve the puzzle of who is at risk for [the] worst symptom experiences,” she says, then researchers and clinicians can develop early intervention strategies to benefit the patient from the moment they are diagnosed through the rest of the patient’s life.
