Cancer patients who've been told to rest and avoid exercise can – and should – find ways to be physically active both during and after treatment, according to new national guidelines. Kathryn Schmitz, PhD, MPH, an associate professor of Epidemiology（流行病学） and Biostatistics（生命统计学） and a member of the Abramson Cancer Center at the University of Pennsylvania School of Medicine, will present these guidelines at an educational session at the 2010 meeting of the American Society of Clinical Oncology（肿瘤学） , aimed at making cancer exercise rehabilitation（复原） programs as common as those offered to people who have had heart attacks or undergone cardiac surgery（心脏外科） . (Exercise Testing and Prescription药方，惯例 for Cancer Survivors: Guidelines from the American College of Sports Medicine) Schmitz, whose previous research reversed decades of cautionary exercise advice given to breast cancer patients with the painful arm-swelling condition lymphedema（淋巴水肿） , led a 13-member American College of Sports Medicine expert panel that developed the new recommendations after reviewing and evaluating literature on the safety and efficacy of exercise training during and after cancer therapy.

"We have to get doctors past the ideas that exercise is harmful to their cancer patients. There is a still a prevailing attitude out there that patients shouldn't push themselves during treatment, but our message -- avoid inactivity – is essential," Schmitz says. "We now have a compelling（强制的，引人注目的） body of high quality evidence that exercise during and after treatment is safe and beneficial for these patients, even those undergoing complex procedures such as stem cell transplants. If physicians want to avoid doing harm, they need to incorporate these guidelines into their clinical practice in a systematic way."

Cancer patients and survivors should strive to（努力） get the same 150 minutes per week of moderate-intensity aerobic exercise（有氧运动） that is recommended for the general public, the panel says. Though the evidence indicates that most types of physical activity – from swimming to yoga to strength training -- are beneficial for cancer patients, clinicians should tailor exercise recommendations to individual patients, taking into account their general fitness level, specific diagnosis and factors about their disease that might influence exercise safety. Cancer patients with weakened ability to fight infection, for instance, may be advised to avoid exercise in public gyms.

One persistent area of concern for cancer patients is change in body mass -- both weight gain and weight loss tied to disease symptoms and treatment side effects. Patients with hormone-based tumors, breast and prostate（前列腺） cancers, tend to gain weight during treatment and frequently have difficulty losing it. Other patients, especially those with gastrointestinal（胃肠的） tumors, suffer from weight loss brought on by loss of appetite（食欲不振） and changes in their ability to swallow and properly digest food. The new guidelines indicate that both groups can benefit from exercise. Studies show, for instance, that exercise for weight control and reduction in body mass may actually reduce the risk of recurrence（循环，重现） for breast cancer patients, and ultimately decrease breast cancer mortality. For patients suffering from cancer-related weight loss, physical activity helps to maintain lean body mass, which can contribute to increased strength and well being.

Schmitz and her colleagues analyzed published studies related to five different adult cancer types (breast, during and after treatment, prostate, hematologic -- with and without stem cell transplant -- colon结肠, and gynecologic妇产科医学的), and reviewed the evidence for multiple health outcomes. The panel found that although there are specific risks associated with cancer treatment that need to be considered when patients exercise, there is consistent evidence that exercise training can lead to improvements in aerobic（需氧的） fitness, muscular strength, quality of life and fatigue（疲劳，疲乏） in breast, prostate, and hematologic cancer patients and survivors. They found the data for colon and gynecologic cancers were too scant（不足的，缺乏的） to draw firm conclusions, and identified several areas requiring further study. Age, for instance, is a critical variable, Schmitz says, since more must be learned about the effects of physical activity in cancer patients over age 65, to develop interventions that may help these patients continue to live and function independently.

The panel urges fitness professionals to enhance their capacity to serve the unique needs of cancer survivors. Schmitz noted that a "groundswell（海啸，地隆） " of training programs now assist physical therapists and fitness trainers in deepening their knowledge of the effects of cancer diagnosis and treatment and improve their skills in this emerging area.

Schmitz also feels strongly that practicing oncologists（肿瘤学家） need to be informed about the new guidelines and their importance, and says that patients can play a role in changing attitudes and clinical practice. Her hope is that patients will read the recommendations and discuss them with their doctors, creating the demand for change that will drive more cancer centers and oncology practices to create and offer cancer exercise rehabilitation services.

Schmitz will present the new guidelines at an educational session on Sunday, June 6, from 4:45 to 6:00 p.m.