A groundbreaking study led by Johns Hopkins Medicine has provided new scientific evidence suggesting that a healthy diet may help prevent low-risk prostate cancer from becoming more aggressive. The study, which is believed to be the first of its kind, was recently published in the journal JAMA Oncology. It focuses on men undergoing active surveillance, a treatment approach where men with low-risk prostate cancer are closely monitored for any signs of the cancer progressing rather than being treated immediately with surgery or radiation. These treatments often come with side effects that can affect a patient’s quality of life, such as incontinence or erectile dysfunction.
Prostate Cancer Grading and Active Surveillance
When prostate cancer is diagnosed through a biopsy, doctors assign a grade group to the cancerous cells based on how they compare to healthy prostate tissue. Grade groups range from 1 to 5. Grade group 1 indicates that the cancer cells look very similar to normal prostate cells and are less likely to spread to other parts of the body, while grade group 5 indicates that the cells are very abnormal and aggressive, meaning they are more likely to grow quickly and spread. Doctors use these grade groups to assess how dangerous the cancer is and determine the best course of action.
For men with grade group 1 prostate cancer, which is considered low-risk, active surveillance is often the recommended approach. In active surveillance, regular biopsies are performed to monitor the cancer for any changes. If the cancer becomes more aggressive, moving to a higher grade group, treatment may be recommended. This shift in the cancer’s grade is called “grade reclassification,” and it’s a key factor in deciding when a patient needs more active treatment. Researchers also use grade reclassification as a way to evaluate the effectiveness of different treatments or lifestyle changes, like diet.
Study Methodology
In this study, the researchers analyzed data from 886 men with grade group 1 prostate cancer who were part of the Johns Hopkins active surveillance program. These men were diagnosed between January 2005 and February 2017. At the start of the study, all participants completed a detailed food survey called the Block 1998 Food Frequency Questionnaire. This questionnaire asked them about their usual eating habits. The researchers used the answers to calculate a “Healthy Eating Index” (HEI) score for each patient, which measures how closely a person’s diet follows guidelines for healthy eating. The HEI score ranges from 0 to 100, with higher scores indicating a healthier diet.
The researchers also used another system to measure the inflammatory potential of each participant’s diet. This system, known as the “Dietary Inflammatory Index” (DII), calculates how likely a person’s diet is to cause inflammation in the body, which is thought to play a role in cancer progression. The energy-adjusted DII (E-DII) takes into account a person’s calorie intake when calculating the score. Inflammation is a natural immune response, but chronic inflammation is linked to many health problems, including cancer.
Key Findings
After a median follow-up period of 6.5 years, the researchers found that 187 men (21%) had experienced grade reclassification, meaning their cancer had progressed to a more aggressive state (grade group 2 or higher). Among these men, 55 (6%) had a significant progression to grade group 3 or higher, which typically requires more aggressive treatment.
The researchers found a clear connection between diet quality and the likelihood of cancer progression. Men with higher HEI scores, meaning those who followed a healthier diet, had a lower risk of their cancer becoming more aggressive. Specifically, for every 12.5-point increase in a man’s HEI score, there was a 15% reduction in the risk of his cancer progressing to grade group 2 or higher, and a 30% reduction in the risk of his cancer progressing to grade group 3 or higher. This means that eating a healthier diet could significantly reduce the likelihood that a man’s low-risk prostate cancer would progress to a stage requiring treatment.
One of the most interesting findings was that this reduction in risk was not linked to the Dietary Inflammatory Index (DII) or the energy-adjusted DII (E-DII) scores. Although the researchers initially hypothesized that reducing inflammation through diet might be one of the reasons for the reduced risk, the study did not find a significant connection between baseline DII/E-DII scores and grade reclassification. This suggests that other factors related to diet quality, such as the overall nutritional balance, might play a larger role in slowing cancer progression than reducing inflammation alone.
Future Directions
Despite these limitations, the study provides compelling evidence that diet quality may play an important role in preventing low-risk prostate cancer from progressing to a more dangerous stage. While more research is needed to fully understand the mechanisms behind this relationship, the findings suggest that making healthier food choices could be a simple, non-invasive way for men with low-risk prostate cancer to improve their chances of avoiding aggressive treatments.
The researchers hope that future studies will further explore how diet impacts prostate cancer progression and whether specific dietary interventions could be developed to help manage the disease. For now, the study adds to a growing body of evidence suggesting that what we eat can have a significant impact on our health, even in the context of cancer.
