(HealthDay)—Seriously distressed cancer patients appear to miss more appointments and have more hospital admissions during treatment, a new study finds.

The U.S. National Comprehensive Cancer Network describes severe as "a mix of anxiety and ." About one-third of have significant distress, it says.

"We know that having cancer is stressful, which means that we have a responsibility to consider a patient's mental well-being when planning a course of action with them," said study author Justin Anderson.

"Focusing on the 'whole patient' allows oncologists to deliver the best possible ," added Anderson, a medical student at the Virginia Commonwealth University School of Medicine.

The study included 54 patients aged 32 to 85 undergoing radiation therapy. Fifteen percent reported severe distress; 29 percent described moderate stress; another 29 percent reported low distress, and one-quarter had no distress.

Although the study doesn't establish a causal relationship, it found that those with higher distress levels were more likely to miss appointments during treatment: 57 percent of patients with severe distress missed one or more appointments, compared with 18 percent of those with moderate, low or no distress.

Also, half the with severe distress were admitted to the hospital during treatment, compared with 11 percent of those with moderate, low or no distress, according to the study.

The researchers also found that the stage of a patient's cancer was associated with distress. Each increase in stage predicted an average increase of 0.8 points on a distress score between 0 and 10.

"While distress does not directly impact a patient's disease, it impacts how she or he copes with treatment, such as the ability to follow a doctor's recommendations and adhere to a treatment plan," Anderson said in a news release from the American Society for Radiation Oncology.

The study was presented Sunday at the society's annual meeting in San Diego. Research presented at meetings is usually considered preliminary until published in a peer-reviewed medical journal.

More information: The U.S. National Cancer Institute has more on the emotional impact of cancer.