Political parties in the United States usually discuss what sets them apart from one other, but two recent announcements demonstrated that Republicans and Democrats had something in common: charismatic, high-profile personalities in their fifties who are battling cancer. The courage and optimism of Elizabeth Edwards, wife of Democratic presidential candidate John Edwards, and Tony Snow, press secretary for the Bush administration, reinforces for me the power of positive thinking for people diagnosed with cancer.

Medical researchers study the effects of mental attitude in cancer patients, using what’s known as the MAC (Mental Adjustment to Cancer) scale. There is even a medical subspecialty called PsychOncology that focuses on a cancer patient’s “social, emotional and spiritual needs.” (The University of Michigan Comprehensive Cancer Center has such a program.) While the findings of most attitude studies are inconclusive, they do offer encouraging signs for anyone who has been diagnosed with cancer. Positive thinking can pay off.

What is a positive attitude? Some say it is maintaining normalcy in your life and not letting cancer stand in the way of your everyday activities. Some say it includes “feeding” yourself with thoughts that each day brings you one step closer to recovery. Many believe that a positive attitude is not about beating cancer but about not allowing cancer to beat you. Others turn to religion or spirituality as a way to actively control negative thoughts and promote positive thinking.

To maintain a positive attitude if you’ve been diagnosed with cancer:

Remember that knowledge is power. Become the most informed person you can be about your type of cancer so you can ask useful questions about your care and treatment. Ask your physician and oncologist, or consult online resources, for information about cancer care centers that specialize in treating your form of cancer. These centers may also conduct clinical trials for which you might be a candidate.

Stay active. Fight the urge to withdraw from the world or others around you. Strive to remain involved and engaged with friends, family members and colleagues. If your illness, or treatment, makes you unable to pursue activities you enjoy, choose other activities. For instance, if you were a runner and are unable to run, take up yoga to help you relax and reduce stress.

Be realistic about your moods. A positive attitude can keep you remarkably resilient and strong mentally, however expecting to be positive all the time is unrealistic; it can even be detrimental. Consider that a cancer diagnosis can be shocking — even frightening — and you require time to digest and process this new information. Bad days will happen from time to time. Of greater concern are ongoing feelings of hopelessness and pessimism.

Seek out positive people and environments. Your state of mind is influenced by the people around you and drawing on the positive energy of family, friends — even healthcare providers — can help you feel more optimistic. The environment of your cancer treatment facility also is important. Your physicians and nurses should be positive and supportive, yet honest, when discussing your cancer and treatment plan. You should feel confident in their abilities, their knowledge and their interest in your health and well-being.

Accept help when you need it. When people close to you offer a helping hand, choose specific things that they can do for you to make you comfortable or to help you accomplish necessary tasks.

Join a support group. Talking with others who are facing the same challenges as you can be comforting and, in some cases, can improve your mental outlook and your health. To locate cancer support groups, consult your physician, your cancer care center or hospital. Personal counseling from a psychologist or therapist also can be beneficial for you and for those you love.

Plan for the future. Organize personal financial and legal matters as soon as you can. Simply addressing these issues and putting plans in order will give you a sense of purpose and accomplishment. Consult an attorney to draw up a will, if you do not already have one. Assign power of attorney to a trusted family member or friend. Determine how you would like your medical care to proceed in the event your illness progresses to a critical stage. Ask the advice of others and weigh it against your own values and beliefs to decide on a course that’s right for you.

A cancer diagnosis is not an automatic death sentence. Cancer research has made great strides in both oncology treatment and clinical trials. People who were diagnosed with cancer and given mere months to live are surviving for many, many years. Focus your energy on what you can do and don’t dwell on what you cannot do. Choose the way you want to live your life — just as Elizabeth Edwards and Tony Snow have chosen to live theirs.