-- Greater intake of pro-inflammatory foods associated with 87% higher risk of death
CHICAGO -- Greater intake of pro-inflammatory foods was associated with worse overall survival (OS) in patients with stage III colon cancer, a secondary analysis of a randomized trial found.
Crude analyses comparing patients in the highest and lowest quintiles of inflammatory food consumption showed significant associations between higher intake of pro-inflammatory foods and both disease-free survival (DFS) and OS. On multivariable analyses, however, only the OS association remained significant:
Patients who had the best survival outcomes were those who consumed less inflammatory diets while also engaging in more physical activity, said Sara Char, MD, of the Dana-Farber Cancer Institute in Boston, who presented the findings during a press briefing at the American Society of Clinical Oncology (ASCO) annual meeting.
Systemic inflammation is implicated in both colon cancer development and progression, Char explained. Elevated levels of inflammatory markers in the blood -- including C-reactive protein (CRP), interleukin (IL)-6, and tumor necrosis factor α receptor 2 (TNFαR2) -- have previously been associated with worse survival outcomes in colorectal cancer.
The empirical dietary inflammatory pattern (EDIP) score, used in the study to measure the inflammatory potential of patients' diets, correlates the intake of 18 specific food groups with plasma levels of CRP, IL-6, and TNFαR2, and has been validated in several large cohorts.
Pro-inflammatory food groups in EDIP include red or processed meats, refined grains, raw tomatoes, and certain fish, while the anti-inflammatory food groups include leafy greens, dark yellow vegetables such as carrots and sweet potatoes, coffee, tea, and, surprisingly, beer, pizza, and wine.
Char was asked about how tomatoes, which are said to have anticancer properties due to lycopene, and pizza ended up on opposite sides of the inflammatory scale.
"One hypothesis is that the lycopene in tomatoes is more bioavailable when it is cooked than raw. And so pizza, having cooked tomato may be a reason why that becomes more anti-inflammatory," she said.
Char cautioned that EDIP should only be viewed as a useful tool for measuring the inflammatory qualities of a diet. "Alcohol is a carcinogen and has other adverse health effects, and that's why this is not a dietary recommendation," she said.
The findings build upon a number of other studies linking inflammation and colon cancer. Earlier this year, randomized trial data showed that low-dose aspirin, an anti-inflammatory medication, reduces recurrence risk in certain patients with stage II/III colon cancer. And a prior study of two large prospective cohorts showed that people whose diets were high in pro-inflammatory foods had a greater risk of developing colorectal cancer.
The current study was a secondary analysis of CALGB/SWOG 80702, a phase III trial that compared 3 versus 6 months of adjuvant FOLFOX (folinic acid, fluorouracil, and oxaliplatin) chemotherapy in patients with resected stage III colon cancer. A second part of the study also showed that adding the COX-2 inhibitor celecoxib did not improve survival outcomes versus placebo.
Julie Gralow, MD, ASCO chief medical officer, pointed out during the Saturday briefing that CALGB/SWOG 80702 was funded by the NIH. "We can squeeze a lot out of our federally funded research if we plan it right."
Earlier in the day, Gralow spoke out against the Trump administration's newly proposed 2026 budget, which includes a nearly 40% cut in federal funding for NIH and the National Cancer Institute.
"Without robust federal funding we risk slowing the pace and the progress of future lifesaving research like the studies we're here to highlight today," Gralow said. "In fact, NIH funding is involved in nearly 99% of all new drug approvals. ASCO is committed to advocating for robust federal cancer research funding." She referred reporters to ASCO's statement on the proposed funding cuts.
The analysis from Char included 1,625 patients enrolled in CALGB/SWOG 80702 who completed food frequency questionnaires at two time points. Participants answered questions about 131 foods that they consumed over the prior 3 months. The amount and frequency of consumption of the 18 food groups in EDIP are added together to create a score, with higher scores corresponding to a more pro-inflammatory diet.
Matching the endpoints in the larger trial, the primary outcome was DFS and the secondary outcome was OS, both analyzed by comparing the highest EDIP quintile (group with the most pro-inflammatory diets) versus the lowest EDIP quintile (group with the most anti-inflammatory diets). Median follow-up was about 4 years for DFS and 5 years for OS.
Overall, patients had a mean age of 60.9 years. Patients in the highest EDIP quintile were more likely to be younger (mean 58.7 vs 61.3 years in the lowest quintile), female (64% vs 48.9%), and have a worse Eastern Cooperative Oncology Group score (35.7% vs 19.4%). They were also less likely to be white (76.6% vs 92%) and more likely to be Black (15.4% vs 3.7%).
Median OS in the highest quintile of pro-inflammatory food intake was 7.7 years, whereas it was not reached among those in the lowest quintile. Subgroup analysis showed a consistent association between pro-inflammatory food intake and worse survival:
Looking at physical activity and diet together, the patients who consumed less inflammatory diets and also maintained higher physical activity -- at least 9 Metabolic Equivalent of Task (MET) hours per week -- had a 63% lower risk of death when compared to those with the highest intake of pro-inflammatory foods (HR 0.37, 95% CI 0.25-0.53) and fewer than 9 MET hours per week.
"We as physicians need to be essentially prescribing healthy diet and exercise," said Gralow. "The combination of the two are synergistic."