The report found communication is key to improving care, with 20% of those surveyed "dissatisfied" with the frequency of communication from their employer following cancer treatment.
According to a 2012 Oxford Economics report more than half a million people in the workplace have cancer and a further 63,000 would like to return to work, but are being held back by a lack of support.
The Maggie's and Unum study found that for many people work can play an important role in recovery. It said work often "recreated a sense of normality and purpose", and provides "a focus beyond cancer".
More than one in four people diagnosed with cancer while in full-time employment said work is important to their sense of identity (28%) and a quarter said it provided them with structure and routine.
About a quarter of respondents (26%) who currently have cancer and were employed at the diagnosis stage said they think less about their medical treatment when they are working.
Andy Evans, compensation and benefits manager for Xerox UK, has been supporting an employee with breast cancer since her diagnosis last November.
"Work was really important to this employee as she felt it was therapeutic and gave her a structure and routine," he said.
"As her line manager, my role was to make sure she felt supported and connected day-to-day and to give her the opportunity to work flexibly or remotely whenever she felt able to."
Lesley Howells, research lead and centre head at Maggie's, said: "Many people living with cancer aren't able or don't want to work after treatment, but for those who can and choose to, it can be vital to their psychological wellbeing.
"Crucially, it can have a hugely positive effect on their self-esteem, empowering them to live well with cancer."