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Obesity and survival among women with ovarian cancer: results from the Ovarian Cancer Association Consortium

View Article: PubMed Central - PubMed

ABSTRACT

Background:: Observational studies have reported a modest association between obesity and risk of ovarian cancer; however, whether it is also associated with survival and whether this association varies for the different histologic subtypes are not clear. We undertook an international collaborative analysis to assess the association between body mass index (BMI), assessed shortly before diagnosis, progression-free survival (PFS), ovarian cancer-specific survival and overall survival (OS) among women with invasive ovarian cancer.

Methods:: We used original data from 21 studies, which included 12 390 women with ovarian carcinoma. We combined study-specific adjusted hazard ratios (HRs) using random-effects models to estimate pooled HRs (pHR). We further explored associations by histologic subtype.

Results:: Overall, 6715 (54%) deaths occurred during follow-up. A significant OS disadvantage was observed for women who were obese (BMI: 30–34.9, pHR: 1.10 (95% confidence intervals (CIs): 0.99–1.23); BMI: ⩾35, pHR: 1.12 (95% CI: 1.01–1.25)). Results were similar for PFS and ovarian cancer-specific survival. In analyses stratified by histologic subtype, associations were strongest for women with low-grade serous (pHR: 1.12 per 5 kg m−2) and endometrioid subtypes (pHR: 1.08 per 5 kg m−2), and more modest for the high-grade serous (pHR: 1.04 per 5 kg m−2) subtype, but only the association with high-grade serous cancers was significant.

Conclusions:: Higher BMI is associated with adverse survival among the majority of women with ovarian cancer.

No MeSH data available.


Related in: MedlinePlus

The association between BMI (per 5 kg m−2) and OS following a diagnosis of invasive ovarian cancer, all subtypes, overall and by study site. Estimates are adjusted for age at diagnosis (continuous), stage (local/regional/distant/unknown), grade (well-/moderately-/poorly plus undifferentiated/unknown) and ethnicity (if <95% of participants at a site shared a common ethnicity) estimates are further adjusted for the interaction of age, stage, grade and/or race with time as appropriate at each site.
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fig1: The association between BMI (per 5 kg m−2) and OS following a diagnosis of invasive ovarian cancer, all subtypes, overall and by study site. Estimates are adjusted for age at diagnosis (continuous), stage (local/regional/distant/unknown), grade (well-/moderately-/poorly plus undifferentiated/unknown) and ethnicity (if <95% of participants at a site shared a common ethnicity) estimates are further adjusted for the interaction of age, stage, grade and/or race with time as appropriate at each site.

Mentions: In multivariate analyses (all histologies combined), we found that women who were overweight (BMI: 25–29.9), obese (BMI: 30–34.9) and morbidly obese (BMI: ⩾35) experienced worse survival compared with women within the normal weight range (pHRs: 1.05 (95% CIs: 0.96–1.15), 1.10 (95% CIs: 0.99–1.22) and 1.15 (95% CIs: 0.98–1.37), respectively). However, in the overweight and morbidly obese groups there was significant heterogeneity between the studies (all P<0.05). Using BMI as a continuous variable, risk of death increased by 3% for each 5-unit increase in BMI over 18.5 kg m−2 (HR: 1.03, (95% CIs: 1.00–1.07)); however, again significant heterogeneity was present between the studies (I2 40%, P=0.03) (Figure 1). Exploration of the heterogeneity showed that the largest difference in pHR was seen for study size with no apparent heterogeneity among the 18 studies, with ⩾200 participants but significant heterogeneity among those with fewer women (Figure 2). The pHR per 5-unit increase in BMI kg m−2 was 1.03 (95% CIs: 1.01–1.06) for studies with ⩾200 women vs 1.21 for studies with <200 women (95% CIs: 0.75–1.96). We also saw significant heterogeneity in other strata, in all except one instance (diagnosis years); the group with significant heterogeneity included at least two, if not all three of the small studies. When we repeated these analyses excluding the three small studies (HSK, JPN and PVD), we found that women who were obese still experienced worse survival (pHR: 1.10 (95% CIs: 0.99–1.23)) than women within the normal weight range (Table 3). This association was similar for those who were morbidly obese (pHR 1.12 (95% CIs: 1.01–1.25)) and the pHR per 5-unit increase in BMI kg m−2 was 1.03 (95% CIs: 1.00–1.06); I2 9%, P=0.35) (Table 3). The evidence of heterogeneity disappeared in the obese and morbidly obese groups; however, there remained significant heterogeneity between the studies in the overweight group (I2 46%, P=0.02). When we further excluded the study site where the confidence interval did not include the pooled estimate (MAL), there was no remaining heterogeneity in the overweight group (I2: 10.4%, P=0.3).


Obesity and survival among women with ovarian cancer: results from the Ovarian Cancer Association Consortium
The association between BMI (per 5 kg m−2) and OS following a diagnosis of invasive ovarian cancer, all subtypes, overall and by study site. Estimates are adjusted for age at diagnosis (continuous), stage (local/regional/distant/unknown), grade (well-/moderately-/poorly plus undifferentiated/unknown) and ethnicity (if <95% of participants at a site shared a common ethnicity) estimates are further adjusted for the interaction of age, stage, grade and/or race with time as appropriate at each site.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4559823&req=5

fig1: The association between BMI (per 5 kg m−2) and OS following a diagnosis of invasive ovarian cancer, all subtypes, overall and by study site. Estimates are adjusted for age at diagnosis (continuous), stage (local/regional/distant/unknown), grade (well-/moderately-/poorly plus undifferentiated/unknown) and ethnicity (if <95% of participants at a site shared a common ethnicity) estimates are further adjusted for the interaction of age, stage, grade and/or race with time as appropriate at each site.
Mentions: In multivariate analyses (all histologies combined), we found that women who were overweight (BMI: 25–29.9), obese (BMI: 30–34.9) and morbidly obese (BMI: ⩾35) experienced worse survival compared with women within the normal weight range (pHRs: 1.05 (95% CIs: 0.96–1.15), 1.10 (95% CIs: 0.99–1.22) and 1.15 (95% CIs: 0.98–1.37), respectively). However, in the overweight and morbidly obese groups there was significant heterogeneity between the studies (all P<0.05). Using BMI as a continuous variable, risk of death increased by 3% for each 5-unit increase in BMI over 18.5 kg m−2 (HR: 1.03, (95% CIs: 1.00–1.07)); however, again significant heterogeneity was present between the studies (I2 40%, P=0.03) (Figure 1). Exploration of the heterogeneity showed that the largest difference in pHR was seen for study size with no apparent heterogeneity among the 18 studies, with ⩾200 participants but significant heterogeneity among those with fewer women (Figure 2). The pHR per 5-unit increase in BMI kg m−2 was 1.03 (95% CIs: 1.01–1.06) for studies with ⩾200 women vs 1.21 for studies with <200 women (95% CIs: 0.75–1.96). We also saw significant heterogeneity in other strata, in all except one instance (diagnosis years); the group with significant heterogeneity included at least two, if not all three of the small studies. When we repeated these analyses excluding the three small studies (HSK, JPN and PVD), we found that women who were obese still experienced worse survival (pHR: 1.10 (95% CIs: 0.99–1.23)) than women within the normal weight range (Table 3). This association was similar for those who were morbidly obese (pHR 1.12 (95% CIs: 1.01–1.25)) and the pHR per 5-unit increase in BMI kg m−2 was 1.03 (95% CIs: 1.00–1.06); I2 9%, P=0.35) (Table 3). The evidence of heterogeneity disappeared in the obese and morbidly obese groups; however, there remained significant heterogeneity between the studies in the overweight group (I2 46%, P=0.02). When we further excluded the study site where the confidence interval did not include the pooled estimate (MAL), there was no remaining heterogeneity in the overweight group (I2: 10.4%, P=0.3).

View Article: PubMed Central - PubMed

ABSTRACT

Background:: Observational studies have reported a modest association between obesity and risk of ovarian cancer; however, whether it is also associated with survival and whether this association varies for the different histologic subtypes are not clear. We undertook an international collaborative analysis to assess the association between body mass index (BMI), assessed shortly before diagnosis, progression-free survival (PFS), ovarian cancer-specific survival and overall survival (OS) among women with invasive ovarian cancer.

Methods:: We used original data from 21 studies, which included 12&thinsp;390 women with ovarian carcinoma. We combined study-specific adjusted hazard ratios (HRs) using random-effects models to estimate pooled HRs (pHR). We further explored associations by histologic subtype.

Results:: Overall, 6715 (54%) deaths occurred during follow-up. A significant OS disadvantage was observed for women who were obese (BMI: 30&ndash;34.9, pHR: 1.10 (95% confidence intervals (CIs): 0.99&ndash;1.23); BMI: &#10878;35, pHR: 1.12 (95% CI: 1.01&ndash;1.25)). Results were similar for PFS and ovarian cancer-specific survival. In analyses stratified by histologic subtype, associations were strongest for women with low-grade serous (pHR: 1.12 per 5&thinsp;kg&thinsp;m&minus;2) and endometrioid subtypes (pHR: 1.08 per 5&thinsp;kg&thinsp;m&minus;2), and more modest for the high-grade serous (pHR: 1.04 per 5&thinsp;kg&thinsp;m&minus;2) subtype, but only the association with high-grade serous cancers was significant.

Conclusions:: Higher BMI is associated with adverse survival among the majority of women with ovarian cancer.

No MeSH data available.


Related in: MedlinePlus