Diet and Survival after Ovarian Cancer: Where Are We and What's Next?

The Role of Nutritional Support in Cured/Chronic Patients

Improvements in Clinical Oncology, due to earlier diagnoses and more efficient therapeutic strategies, have led to increased numbers of long-term survivors, albeit many with chronic diseases. Dealing with the complex care needs of these survivors is now an important part of Medical Oncology. Suitable diet and physical activity regimes will be important in maintaining their health. This paper will review what we know and what we can do in the near future for these patients.

Pre-diagnosis diet and survival after a diagnosis of ovarian cancer

Background:

The relationship between diet and survival after ovarian cancer diagnosis is unclear as a result of a limited number of studies and inconsistent findings.

Methods:

We examined the association between pre-diagnostic diet and overall survival in a population-based cohort (n=811) of Australian women diagnosed with invasive epithelial ovarian cancer between 2002 and 2005. Diet was measured by validated food frequency questionnaire. Deaths were ascertained up to 31 August 2014 via medical record review and Australian National Death Index linkage. We conducted Cox proportional hazards regression analysis, controlling for diagnosis age, tumour stage, grade and subtype, residual disease, smoking status, body mass index, physical activity, marital status, and energy intake.

Results:

We observed improved survival with highest compared with lowest quartile of fibre intake (hazard ratio (HR)=0.69, 95% CI: 0.53–0.90, P-trend=0.002). There was a suggestion of better survival for women with highest compared with lowest intake category of green leafy vegetables (HR=0.79, 95% CI: 0.62–0.99), fish (HR=0.74, 95% CI: 0.57–0.95), poly- to mono-unsaturated fat ratio (HR=0.76, 95% CI: 0.59–0.98), and worse survival with higher glycaemic index (HR=1.28, 95% CI: 1.01–1.65, P-trend=0.03).

Conclusions:

The associations we observed between healthy components of diet pre-diagnosis and ovarian cancer survival raise the possibility that dietary choices after diagnosis may improve survival.

Weight Loss and Mortality in Overweight and Obese Cancer Survivors: A Systematic Review

Background

Excess adiposity is a risk factor for poorer cancer survival, but there is uncertainty over whether losing weight reduces the risk. We conducted a critical review of the literature examining weight loss and mortality in overweight or obese cancer survivors.

Methods

We systematically searched PubMed and EMBASE for articles reporting associations between weight loss and mortality (cancer-specific or all-cause) in overweight/obese patients with obesity-related cancers. Where available, data from the same studies on non-overweight patients were compared.

Results

Five articles describing observational studies in breast cancer survivors were included. Four studies reported a positive association between weight loss and mortality in overweight/obese survivors, and the remaining study observed no significant association. Results were similar for non-overweight survivors. Quality assessment indicated high risk of bias across studies.

Conclusions

There is currently a lack of observational evidence that weight loss improves survival for overweight and obese cancer survivors. However, the potential for bias in these studies is considerable and the results likely reflect the consequences of disease-related rather than intentional weight loss. There is a need for stronger study designs, incorporating measures of intentionality of weight loss, and extended to other cancers.

Nutrition and physical activity guidelines for cancer survivors

Cancer survivors are often highly motivated to seek information about food choices, physical activity, and dietary supplements to improve their treatment outcomes, quality of life, and overall survival. To address these concerns, the American Cancer Society (ACS) convened a group of experts in nutrition, physical activity, and cancer survivorship to evaluate the scientific evidence and best clinical practices related to optimal nutrition and physical activity after the diagnosis of cancer. This report summarizes their findings and is intended to present health care providers with the best possible information with which to help cancer survivors and their families make informed choices related to nutrition and physical activity. The report discusses nutrition and physical activity guidelines during the continuum of cancer care, briefly highlighting important issues during cancer treatment and for patients with advanced cancer, but focusing largely on the needs of the population of individuals who are disease free or who have stable disease following their recovery from treatment. It also discusses select nutrition and physical activity issues such as body weight, food choices, food safety, and dietary supplements; issues related to selected cancer sites; and common questions about diet, physical activity, and cancer survivorship.

The impact of body weight on ovarian cancer outcomes

BACKGROUND

Obesity is a known risk factor and poor prognostic factor for many comorbidities including cancer. However, the influence of body mass index (BMI) on ovarian cancer outcomes is inconclusive. Therefore, the objective of this study was to evaluate the impact of BMI and weight changes on survival in patients with advanced ovarian cancer after primary treatment.

METHODS

All patients with a diagnosis of advanced epithelial ovarian cancer from January 2000 to December 2007 undergoing primary cytoreductive surgery and adjuvant chemotherapy were identified. Patients were divided into 3 categories: underweight/normal weight (BMI, <25 kg/m), overweight (BMI, 25-30 kg/m), and obese (BMI, >30 kg/m). Adjusted hazard ratios for progression-free survival (PFS) and overall survival (OS) were calculated via Cox proportional hazards models.

RESULTS

One hundred ninety-eight patients met the inclusion criteria. For all patients, the mean BMI was 26 kg/m (range, 16.4-49.1 kg/m), with 43% of patients being classified as normal weight, 29% overweight, and 28% as obese. Median 5-year OS was 48.2 months (95% confidence interval, 16.4-49.1 months), and no differences in OS were noted between BMI groups. Unadjusted median PFS for patients with normal weight was 13.7 months, compared with 15.5 and 17.9 months for the overweight and obese groups. Adjusted analysis of BMI over time indicates a trend of increased risk for patients who gain weight in the 6 months after primary therapy on disease progression (hazard ratio, 1.68; 95% confidence interval, 0.87-3.26).

CONCLUSIONS

After adjustment for confounders, such as stage, grade, histology, age, and debulking status, data suggest a trend toward a shorter PFS in patients with a normal BMI. However, OS was not significantly related to BMI, and weight change in the 6 months after completion of treatment had no effect on PFS or OS. Further research should be directed at elucidating relationships between weight and cancer biology.

A randomized parallel-group dietary study for stages II-IV ovarian cancer survivors

OBJECTIVE

Few studies have examined the dietary habits of ovarian cancer survivors. Therefore, we conducted a study to assess the feasibility and impact of two dietary interventions for ovarian cancer survivors.

METHODS

In this randomized, parallel-group study, 51 women (mean age, 53 years) diagnosed with stages II-IV ovarian cancer were recruited and randomly assigned to a low fat, high fiber (LFHF) diet or a modified National Cancer Institute diet supplemented with a soy-based beverage and encapsulated fruit and vegetable juice concentrates (FVJCs). Changes in clinical measures, serum carotenoid and tocopherol levels, dietary intake, anthropometry, and health-related quality of life (HRQOL) were assessed with paired t-tests.

RESULTS

The recruitment rate was 25%, and the retention rate was 75% at 6 months. At baseline, 28% and 45% of women met guidelines for intake of fiber and of fruits and vegetables, respectively. After 6 months, total serum carotenoid levels and α- and β-carotene concentrations were significantly increased in both groups (P<0.01); however, β-carotene concentrations were increased more in the FVJC group. Serum β-cryptoxanthin levels, fiber intake (+5.2g/day), and daily servings of juice (+0.9 servings/day) and vegetables (+1.3 servings/day) were all significantly increased in the LFHF group (all P<0.05). Serum levels of albumin, lutein and zeaxanthin, retinol, and retinyl palmitate were significantly increased in the FVJC group (all P<0.05). No changes in cancer antigen-125, anthropometry, or HRQOL were observed.

CONCLUSION

Overall, this study supports the feasibility of designing dietary interventions for stages II-IV ovarian cancer survivors and provides preliminary evidence that a low fat high fiber diet and a diet supplemented with encapsulated FVJC may increase phytonutrients in ovarian cancer survivors.

Current academic clinical trials in ovarian cancer: Gynecologic Cancer Intergroup and US National Cancer Institute Clinical Trials Planning Meeting, May 2009

OBJECTIVE

To review the current status of large phase academic clinical trials for women with ovarian cancer, address cross-cutting issues, and identify promising areas for future collaboration.

METHODS

In May 2009, the Gynecologic Cancer Intergroup, which represents 19 Cooperative Groups conducting trials for women with gynecologic cancer, and the US National Cancer Institute convened a Clinical Trials Planning Meeting.

RESULTS

The topics covered included the impact of new developments in cancer biology upon molecular targets and novel agents, pharmacogenomics, advances in imaging, the potential benefit of diet and exercise to reduce the risk of recurrence, academic partnership with industry, statistical considerations for phases 2 and 3 trials, trial end points, and symptom benefit and health-related quality-of-life issues. The clinical trials discussed spanned the spectrum of ovarian cancer from initial diagnosis, staging, and cytoreductive surgery to consolidation chemotherapy, and treatment of recurrent disease.

CONCLUSIONS

Ongoing and effective collaboration with industry, government, and patients aims to ensure that the most important scientific questions can be answered rapidly. We encourage women with ovarian cancer and their oncologists to consider participation in the academic clinical trials conducted by the member groups of the Gynecologic Cancer Intergroup.