The findings, which have not yet been published, were presented this week at the annual meeting of the American Association for Cancer Research (AACR) in the US.
The research may serve to calm concerns about the safety of aspartame, which were significantly fuelled by a recent Italian study that linked the substance to cancer in rats.
The new federally-funded study was conducted by scientists at the National Cancer Institute, who used diet-consumption questionnaires to examine the link between aspartame intake and brain and hematopoietic- or lymphoma and leukemia- cancers.
"Compared with no consumption of aspartame-containing beverages, increasing levels of consumption were not associated with any risk of overall hematopoietic caner or brain cancer," concluded the report.
The scientists tracked the diets of 340,045 men and 226,945 women aged 50-69 by asking them to report how much soda, fruit juice and iced tea they drank in the previous year. The participants were then asked if they preferred diet versions or regular versions of these drinks.
The responses were used as a guideline to ascertain participants' past accumulative consumption of such beverages.
But despite the fact that the questionnaires were conducted between 1995 and 1996- a time when diet sodas mainly contained the controversial sweetener- the questions were not expressly targeted at determining consumption of specific aspartame-containing drinks.
In addition, and as with all observational studies, a certain margin of error exists for participants' memory limitations.
These limitations were acknowledged by the scientists who presented their work at the AACR meeting.
"We cannot discount the possibility that the measurement error associated with this method of self-report of diet consumption might have prevented us from detecting a small but true association with cancer," said researcher Dr Unhee Lim.
"But with the consideration that this study- like any other current epidemiologic studies of diet and cancer- has limitations due to measurement error and observation of mostly moderate consumers, we report that our observation does not suggest an elevated risk of lymphoma, leukemia and brain cancers with aspartame consumption," she told FoodNavigator-USA.com.
Dr Lim added that no public health recommendations or any conclusion beyond the study's observation can be extracted from the findings.
The study is currently being reviewed for scientific validity by experts in the field, and will not be published until this review is complete. Dr Lim was unable to say when or where it is likely to be published.
"It all depends on the reviewers' decision," she said, adding that she and her colleagues are deferring more in-depth discussion until after publication.
Yet despite the fact that nothing has appeared in print, the study has caused significant excitement amongst Aspartame manufacturers, who are keen to have the safety of their products confirmed in order to ease consumer fears.
"It is very good to see one more confirmation that aspartame is completely safe," said NurtaSweet chief executive officer Craig Petray.
"It's not a surprise to us, but we certainly welcome the findings and hope consumers feel more comfortable using aspartame in the future," he added.
The watchful consumer advocacy group Center for Science in the Public Interest (CSPI) also admitted that the study helped "allay cancer concerns," but added that the study's means of measuring aspartame consumption was "imprecise."
The group also claimed the age of the respondents could be another limitation of the study, as it has not allowed for the potential detection of cancer in "truly elderly people."
Aspartame is currently used in a variety of food and beverage items, such as yogurt, desserts and carbonated drinks. The US Food and Drug Administration (FDA) first approved it for use in certain products in 1974. In 1996 its use as a general purpose sweetener was approved.
Current estimation sets the nation's total aspartame consumption at 8,040 tons per year, with the acceptable daily intake set by the FDA being 50mg aspartame/kg body weight.
Since 1988 the FDA has received around 4,000 consumer complaints linked to the sweetener, with symptoms including headaches, dizziness, mood change and vomiting.