(Reuters Health) - Cancer patients need to be prepared for serious side effects from chemotherapy, and hospitalization is one that happens much more often in the real world than in drug trials, according to a new study.

Researchers found that people with advanced lung cancer receiving chemotherapy in real-world settings were almost eight times more likely to be hospitalized during treatment than those participating in clinical trials, which are highly controlled and regulated.

What's more, very few clinical trials even report how often participants are hospitalized during the research, the study authors found.

"Clinical trials should be routinely reporting their hospitalization rates so we know what to expect," said senior author Dr. Monika Krzyzanowska, a medical oncologist at the Princess Margaret Cancer Center in Toronto, Canada.

Krzyzanowska and her colleagues write in JAMA Oncology that the number of times a person goes to the hospital with treatment complications is important to the patient and to the hospital.

A patient's quality of life may suffer if they are hospitalized, and a hospital's reputation or reimbursement may suffer if its patients are repeatedly hospitalized.

"I think that (hospitalization is) actually much more common than we ever anticipated," Krzyzanowska said.

For the new study, the researchers looked at data on how many times patients with lung cancer were hospitalized while receiving chemotherapy.

They searched medical databases and found five clinical trials with a total of 3,962 people that specified how many hospitalizations occurred, and compared them to five studies with 8,624 people receiving chemotherapy in real-world settings.

Overall, 51 percent of the real-world patients were hospitalized during their treatments, compared to 16 percent of those in clinical trials.

Some of the research looked at factors related to the risk of hospitalization like the type of chemotherapy used and hospital performance measures, but results varied from study to study.

Based on the data, Krzyzanowska told Reuters Health that she can't say with confidence which factors may be tied to an increased risk of being hospitalized.

But, she said, high hospitalizations are likely to be found among people with other types of cancers and for those on other types of treatments.

"I think this is unfortunately a common phenomenon across disease site and treatment regimen," Krzyzanowska said.

The researchers suggest several possible explanations for the differences in hospitalization rates.

First, the patients in highly selective clinical trials are different from real-world patients, who are likely to have other conditions in addition to cancer. In this study, people receiving chemotherapy in real-world settings were also older, on average, than those in clinical trials.

Another possibility is that unlike people in the real world, complications or side effects among those in closely monitored clinical trials are treated before they lead to hospitalizations.

Knowing how much time patients may spend in hospitals during chemotherapy might help them and their doctors in deciding which treatment is right, Krzyzanowska said.

"I think the low-hanging fruit is that clinical trials should start reporting hospitalizations," she said of the findings.

With that kind of data, the researchers suggest, scientists can calculate the risk of hospitalization per month of chemotherapy and ultimately provide that to patients.

Krzyzanowska also said she'd like to look at what factors drive hospitalizations among cancer patients receiving chemotherapy.

"I definitely think there is a substantial portion of people whose symptoms can be managed earlier so they don’t end up in the hospital," she said.

If people are concerned about their quality of life during treatment, Krzyzanowska said, they should ask their oncologist about the likelihood of being hospitalized because of treatment.

SOURCE: http://bit.ly/1LAzRMY JAMA Oncology, online September 17, 2015.