26 APR 2012 - Nutrition and physical activity guidelines for cancer survivors - CA: A Cancer Journal for Clinicians - Wiley Online Library

Nutrition and physical activity guidelines for cancer survivors - CA: A Cancer Journal for Clinicians 

".... After receiving a diagnosis of cancer, survivors soon find there are few clear answers to even the simplest questions, such as: Should I change what I eat? Should I exercise more? Should I gain or lose weight? Should I take dietary supplements? Cancer survivors receive a wide range of advice from many sources about foods they should eat, foods they should avoid, how they should exercise, and what types of supplements they should take, if any. Unfortunately, this advice is often inconsistent and not supported by data...."

Ovarian Cancer

Ovarian cancer is the leading cause of death from gynecologic malignancies in the United States.4 Symptoms tend be nonspecific, making early detection difficult. Consequently, most ovarian cancers are diagnosed at an advanced stage when the prognosis is poor, with an overall 10-year survival rate of 39%.4 The role of lifestyle factors in ovarian cancer prognosis is largely unknown.138, 242 To our knowledge, only 3 studies139, 140, 243 have evaluated the role of dietary factors in ovarian cancer survival. These 3 studies were based on prospective follow-up of the cases participating in case-control studies and evaluated the association between prediagnosis dietary intake and mortality outcomes. One study, conducted in China, focused on the role of green tea and reported that a higher frequency and quantity of green tea intake after diagnosis was associated with better survival.243 The other 2 studies, conducted in Australia140 and the United States,139 suggested that prediagnosis dietary intake may influence the survival experience of patients with ovarian cancer. Both studies tended to support the association of fruit and vegetable consumption with better survival. Dairy food intake was associated with poorer survival in one of the studies,140 while in the other, only milk consumption and not total dairy food consumption was inversely associated with survival.139 Meat consumption was associated with better survival in the Australian study,140 and with lower survival in the study conducted in the United States.139 While these studies controlled for most relevant covariates, they did not include treatment information. In addition, these studies did not evaluate dietary intake after diagnosis. However, they do suggest that dietary intake may influence ovarian cancer survival and warrant further research in this area.

Only one study, also following cases in a case-control study for mortality, has evaluated the role of physical activity in ovarian cancer survival.244 Prediagnosis physical activity was ascertained as hours per week for 3 life periods (childhood, between ages 18-30 years, and in recent years). The study also evaluated the role of changes in physical activity over time. There was not much indication of an association with survival for any of these variables, except for physical activity at aged 18 to 30 years, which seemed to be associated with better survival for women with early stage ovarian cancer and with worse survival for women with an advanced stage of disease at diagnosis.245

The relationship between excess weight and ovarian cancer survival has been evaluated by relatively few studies. Obesity may affect ovarian cancer survival by having a negative impact on optimal surgical and cytotoxic treatment and increasing the likelihood of postoperative complications.246 Overall, the literature evaluating the association between weight/BMI and ovarian cancer survival is limited and inconclusive.76, 242 Cohort studies evaluating the role of prediagnosis obesity obtained at baseline on ovarian cancer mortality have generally found elevated ovarian cancer mortality among obese women.234, 247 Other studies evaluating the role of prediagnosis BMI on ovarian cancer survival by following cases in a case-control study or clinical trial (using baseline data) have offered conflicting results.242 The role of postdiagnosis body size and weight changes on ovarian cancer survival is largely unknown. Only one study has reported on weight changes during chemotherapy and ovarian cancer survival and found that, among patients with advanced ovarian cancer, weight loss during chemotherapy was associated with worse prognosis; however, it is difficult to determine whether this weight loss was involuntary or intentional.248

In summary, while the current evidence is limited and inconclusive, it points to a possible role of dietary factors, physical activity, and body size and weight changes in modulating ovarian cancer survival, and for physical activity in improving the quality of life among ovarian cancer survivors. Further studies are needed before public health recommendations can be made.