SWAMPSCOTT – Respiratory disease killed her parents, so Cathy McDermott asked for a chest X-ray during her 1998 checkup even though she felt good and didn’t think she had a reason to be worried. She was wrong.”I found out a week later I had lung cancer. It was terrible; I thought it was a death sentence,” she said.Follow-up tests confirmed the cancer diagnosis and, two months after the X-ray, doctors removed part of the Lynn resident’s left lung. She was 65 at the time.Then, in January, when McDermott’s daughter, Maryanne Sheckman, went for her first checkup in five years, her doctor asked Sheckman about her persistent cough. Sheckman claimed she barely noticed the cough and had not had any other respiratory illness symptoms, but on the day her mother celebrated her 81st birthday, Scheckman absorbed the news that she had lung cancer. The diagnosis left her devastated, even prompting her to tell her husband, Swampscott physician Peter Sheckman, “?I’m so sorry I am going to leave you.'”Surgeons removed one-third of her right lung in March and Sheckman spent five weeks recovering from surgery.Like her 81-year-old mother, Sheckman, 55, gets regular evaluations to determine if she remains cancer-free. Both women said they feel great.With November highlighted as Lung Cancer Awareness Month by medical associations, mother and daughter are urging people who may face lung cancer risks to get preventative tests, including modern medical scans like the three-dimensional computer imaging equipment that pinpointed Sheckman’s cancer.According to the American Cancer Society, lung cancer is the leading cause of cancer death in the United States for men and women, but it is also the most preventable form of cancer death, according to state college educators and American Cancer Society representatives pushing to reduce student smoking on the University of Massachusetts-Lowell campus.Tobacco use, according to the American Cancer Society, accounts for almost 30 percent of all cancer deaths and 87 percent of lung cancer deaths.Sheckman is a former smoker and she knew the ordeal her mother endured 15 years ago, but she never considered the prospect of a cancer diagnosis, even though she worked as a nurse and is now a state health care investigator.Sheckman took up walking to spur her recovery and her mother – who also had a career in nursing and took a job as a flight attendant at the age of 62 – dove into her work to speed up her recovery. Both women said three potential risk factors – age, smoking history and family history – offer good reasons for someone to ask a doctor for a lung scan.”That $100 copayment was the best $100 I ever spent,” said Sheckman.Mother and daughter said preventative screenings aimed at identifying lung cancer need the same popular attention and focus given in recent years to breast cancer awareness. Sheckman said younger people need to be aware of lung cancer risks.”Be safe instead of sorry. Don’t think it can’t happen to you,” she said.