Harvard Reports on Cancer Prevention
Volume II: Prevention of Cancer

Introduction

Harvard's Center for Cancer Prevention was established on the premise that prevention offers the best hope for significantly reducing the suffering and death caused by cancer. As the burden of cardiovascular disease continues to fall¹ and cancer mortality stays steady², the relative importance of cancer continues to rise. To bring the growing knowledge about cancer and options for prevention to the public, we summarized in the first report from the Center general information on the causes of cancer.³ Prevention requires that in addition to defining the causes of cancer, the public must be adequately informed as to what places people at risk of cancer. Additionally, what measures they can take as individuals to reduce their risk, what social policies can be implemented to reduce the cancer risk for the population as a whole, and what healthcare providers can do to facilitate the reduction in cancer risk, must be explicit.

The Harvard Report on Cancer Prevention is designed to meet this educational need by providing a comprehensive overview of what we know about cancer risk in the United States and the preventive measures we can take to reduce the burden of cancer. The First Report reviewed the causes of human cancer considering a wide range of potential sources of risk such as smoking, diet, sedentary lifestyle, occupational factors, viruses, and alcohol.³ It concluded that over 50 percent of cancer could be prevented if we implement what we already know about the causes of cancer.

Volume 2, Prevention of Human Cancer, summarizes research on prevention programs, public education campaigns, and social policy measures for preventing cancer. Working in schools, health clinics, and workplaces as well as through the mass media and in the political arena, social scientists and health educators are designing innovative and effective health promotion programs to help people quit smoking, eat healthier, and exercise more.

In subsequent years, the Center will publish updates of the report so that readers can be kept abreast of developments in this fast-breaking field of inquiry.

Volume II: Prevention of Cancer

Purpose
In the First Report from the Center on the Causes of Cancer, we prepared a report that aimed to bring order to the cacophony of information that saturates the media with stories about risk of cancer. We took stock and summarized the evidence drawing attention back to smoking, diet, and exercise as major risk factors for cancer.

Here, in the Second Report from the Center, we present a framework for implementing prevention programs to reduce the burden of cancer. As the first report summarized the knowledge base of risk factors and causes of cancer, this report now sets forth action that can be taken to reduce the burden of cancer in the United States . Traditionally, public health researchers have concentrated their efforts in building the scientific knowledge of what causes cancer, both at a cellular and population level. Much less attention has been paid to the translation of this knowledge into action. Here, building on the work of Julius Richmond, MD, who served as Surgeon General and Assistant Secretary of Health under President Carter, we set forth a framework for cancer prevention. This social strategy serves as a blueprint for prevention goals and how to achieve them.⁴ Dr. Richmond, when initiating the 1979 report "Healthy People: The Surgeon General's Report on Health Promotion and Disease Prevention" set quantitative health goals for the nation and defined three components for a framework to achieve the goals.⁵ These components are:

In this report, we use this structure to review the strategies for cancer prevention. We have prepared this report with both scientific and lay audiences in mind. Each chapter addresses prevention through these three components; summarizes the key points, and makes recommendations for prevention. Finally, a set of key references for further reading is included as a resource for those building on this report. We have deliberately avoided using technical language to bring this material to policymakers, the news media, and the general public.

Because less attention has been paid over the years to the practical means of translation of our knowledge about the causes of cancer to the prevention of cancer, the knowledge base in some areas of cancer prevention is scanty. The generalizability of a nutritional intervention in one social setting to other settings for instance, may be uncertain. We cannot realistically expect however, even in a world which invested more heavily in intervention research, that we will be able to test every potential intervention rigorously in every category age, gender, ethnicity, or educational attainment. In this report, we have taken a pragmatic approach to assessing the available evidence, and some material inevitably reflects assumptions made according to the best available evidence. This is the classic dilemma in Public Health—Do we have sufficient knowledge to take action? In the case of cancer, where several decades may elapse between critical exposures to carcinogens and the clinical diagnosis of cancer, we do not have the luxury of waiting until the scientific evidence is complete before deciding on a course of action.

Contents
Prevention of Human Cancer is organized by type of risk exposure rather than by cancer site (e.g., lung, breast, prostate, and large intestine). Focusing on risk exposures builds on the presentation in the first Report pointing to those factors that should be the focus of intensive action building political will to generate additional resources to develop and implement the social strategy outlined in this report. The chapters in this report deal with major risk factors for cancer that account for over 50 percent of the reduction in the burden of cancer that could be achieved if these changes are implemented.

The material in this volume assumes, and does not reiterate, the evidence on the causes of cancer presented in the first volume. They should be read side by side, if the reader wants to get a complete picture of the scientific rationale for the interventions discussed in this second volume.

The final chapter provides a summary of the report's major conclusions. Attention is given to the need for integrated approaches to cancer prevention that include community level programs aimed at behavioral change, commonly considered health education messages, structural or policy level changes that makes the environment one that promotes a lower risk of cancer, and finally through health services that promote and reinforce a healthier lifestyle.

Acknowledgments — We are grateful to our colleagues who contributed to this report. It is their participation that makes this report a unique contribution to the field of cancer prevention:

We are also grateful to Vincent L Gregory, Jr., who serves as chair of the Advisory Board for the Harvard Center for Cancer Prevention, for his leadership and inspiration; to Anna Mariani for her work coordinating the production of this report, and to Alix Smullin and Mark Bockman for providing logistical support.

We also thank the following experts for serving as reviewers:

Development of the Harvard Report on Cancer Prevention was supported by the generous contributions of Margorie G. and Vincent L. Gregory Jr.

Editors

References