The fact remains, however, that for the last four years of the study, the women who ate a low-fat diet incorporating more whole grains, fruits and vegetables did indeed have a lower risk of developing ovarian cancer.
Prentice notes, "It takes some time for dietary change to express itself in chronic disease." And although we do not yet understand the biological mechanisms, he suggests that hormones may play a role.
Byers also stresses the importance of hormones, adding that a better understanding of the hormonal factors affected by dietary change might offer a clue.
And the fact that the apparent drop in ovarian cancer risk took four years to manifest suggests such changes take time to kick in.
"I wouldn't expect a low-fat dietary intervention to have an immediate impact on the risk of ovarian cancer," DuBeshter said. "Any dietary intervention would take time to have an impact. The findings of this study bear this out."
Byers cautions, however, that although a low-fat diet may take time to have effect, "this could also be just the play of chance."
As such, Byers said he prefers to focus more on the bigger picture of the study, which showed no significant effects of the low-fat diet.
"The time-related patterns are interesting and hopeful, but thin ice," he added.
Compounding this possibility is the fact that ovarian cancer is a relatively rare disease -- a point that Prentice himself acknowledges.
"This is an important but rare disease," Byers concurred. "That it was observed to be rare in this study is not surprising."
DuBeshter, however, feels that "the low risk of ovarian cancer wasn't a factor in this study's results, since the statistical analysis was carefully done."
For young women who hope to reduce their ovarian cancer risk, DuBeshter recommends a few preventive measures.
"Use oral contraceptives for up to five years," he suggested. "This has been shown to reduce the risk of ovarian cancer by 50 percent.
"Alternatively, for women with a family history of ovarian or breast cancer, genetic counseling and testing may be warranted," he added.
Similarly, Byers emphasizes that if women's concerns stem from a family history of ovarian cancer, they should seek counseling about their possible genetic risk.
Dietitian Denise Snyder, clinical trials manager at Duke University School of Nursing in Durham, N.C., said, "We do need to keep in mind that just because someone does follow a low-fat diet, it does not mean that they won't get ovarian cancer."
But still, she added, "Following a low-fat diet may reduce their risk of developing ovarian cancer."
Indeed, as Snyder points out, the study is yet another that supports the American Cancer Society guidelines for the population on cancer prevention.
In addition, she encourages women to maintain a healthy weight, engage in regular physical activity, and limit their alcohol intake to one drink per day.
Study author Prentice also cautions that this is not a magic bullet in the prevention of ovarian cancer in postmenopausal women.
"This is just one dietary maneuver of several in postmenopausal women," he said.