More than one in two cancer patients experienced symptoms of long COVID-19 for more than six months after initial infection, according to a new study at a US cancer centre.
The findings are comparable to reported incidence of long COVID-19 in the general population but also show that women undergoing cancer treatment seem at higher risk than men. The study is published in the journal eLife.
In the general population, reports of the prevalence of long COVID-19 - also known as post-acute sequelae of SARS-CoV-2 infection (PASC) - vary from 10 per cent to 87 per cent, with symptoms persisting beyond 30 days in patients who had severe initial COVID-19 symptoms or were hospitalised.
"Although cancer patients fall into a higher COVID-19 risk group there is limited data on PASC in cancer patients and how it affects their progression, care and treatment," said lead author Anne-Marie Chaftari, Associate Professor, the University of Texas MD Anderson Cancer Center, Texas, US.
"In order to provide a better understanding of post-COVID-19 management among cancer patients, we sought to characterise the patterns of long COVID-19 specifically in these patients," said Chaftari.
According to the study, the team of scientists identified patients receiving care at the University of Texas MD Anderson Cancer Center who were diagnosed with COVID-19 between March and September 2020 and followed their progress for up to 14 months via remote symptom monitoring and their usual hospital visits.
Questionnaires were sent out to patients daily for 14 days after initial COVID-19 diagnosis, then weekly for three months, and monthly thereafter, the study said.
Patients were asked to record symptoms including fatigue, cough, chest tightness, difficulty breathing, headache, fever, altered sense of smell or taste, muscle aches, gastrointestinal (GI) symptoms, sleep disturbance and any limitations with activities of daily living, the study said.
Long COVID-19 was defined as COVID-19-related symptoms persisting beyond 30 days of diagnosis or the emergence of new COVID-19 symptoms.
The team collected data for 312 cancer patients, of whom 188, or 60 per cent, developed long COVID-19. Those who had relapsed or had treatment-resistant cancer at baseline, or those who had more severe acute COVID-19 infections, were less likely to develop long COVID-19, the study said.
They found that female cancer patients had a higher rate of long COVID-19 compared with male cancer patients, with 63 per cent versus 51 per cent, the study said.
There was otherwise no difference in the characteristics of patients who developed long COVID-19 and those who did not - risk factors such as depleted white blood cells, needing oxygen, being hospitalised for COVID-19 or multi-organ failure were similar in both groups, the study said.
The most common long COVID-19 symptoms were fatigue, sleep disturbances, muscle pain and GI symptoms, the study said.
One discovery the authors found intriguing was that patients with high blood pressure (BP) were less likely to develop long COVID-19, the study said.
This was surprising given that high BP is a known risk factor for more severe acute COVID-19, but a similar finding was also seen in another study of long-COVID-19 in immunocompromised patients, the study said.
The link between BP and risk of severe acute COVID-19 is thought to be due to the binding of the COVID-19 spike protein to angiotensin-converting enzyme 2 (ACE-2), the target of many BP-lowering drugs. These findings might rule out this mechanism being important for the development of long COVID-19, the study said.
Among the 188 cancer patients who developed long COVID-19, 59 patients, or 31 per cent, were readmitted to hospital, but only 16 patients, or 8.5 per cent, were readmitted for COVID-19-related reasons, with most having symptoms that could be managed by outpatient care, the study said.
"Our study found that long COVID-19 occurred in the majority of our cancer patients and was more prevalent in women than men," concluded senior author Issam Raad, professor, the University of Texas MD Anderson Cancer Center.
"Even in this high-risk patient population, long COVID-19 was not associated with a high rate of hospital admissions. We also found no underlying condition or severity of illness during acute COVID-19 that would predict long COVID-19," said Raad.