ASCO Takeaways for Primary Care Physicians

Editor's Note:
The 2015 annual meeting of the American Society of Clinical Oncology (ASCO), held May 29-June 2 in Chicago, featured many important studies that may affect how primary care physicians (PCPs) treat their patients at high risk for cancer, those with cancer, and those who have survived a cancer diagnosis.

Medscape asked Larissa Nekhlyudov, MD, MPH, an associate professor of population medicine at Harvard Medical School, general internist at Harvard Vanguard Medical Associates, and clinical director of internal medicine for Cancer Survivors at the Dana-Farber Cancer Institute, David B. Perini, Jr. Quality of Care Clinic, to provide takeaways on how these study results may influence primary care physicians' practice.

The studies were presented as oral abstracts at ASCO, the year's most important cancer meeting, and were chosen as those most likely to affect primary care.

Cancer Survivors

Statin Use and Cancer Mortality

An interesting presentation for PCPs at ASCO this year, abstract 1506, demonstrated that statin use was associated with a 22% reduction in deaths from various cancer types in postmenopausal women and a 55% reduction in deaths from bone and connective tissue cancers. However, both the study investigators and unaffiliated cancer experts pointed out that the study, a post hoc analysis including 146,326 participants with more than 14 years of median follow-up, does not establish causality and that postmenopausal women should not be taking statins to lower their risk of dying from cancer.

The mechanism by which statins may reduce cancer is unclear; study investigators believe it may be related to the lower cholesterol levels induced by lipid-lowering medications.

Dr Nekhlyudov: From the cardiovascular perspective, recent recommendations are suggesting that more patients may benefit from statin use. The question of whether statins may also lead to improvements in cancer outcomes is intriguing.

The study did show a potential benefit, though it appears that there was also a benefit from other lipid-lowering agents. I think that it is too early to recommend statins to reduce cancer-related death, but we may counsel patients with cancer about potential beneficial effects of these medications. It is also comforting to know that there does not appear to be detrimental effects on cancer outcomes.

Evidence about statins continues to evolve. We need to continue exploring the mechanism behind the underlying pathophysiology of cholesterol in disease prevention.

Survival After Childhood Cancer

Abstract LBA2—one of four studies presented in the plenary session, which features the year's most clinically significant abstracts—evaluated late mortality among childhood cancer survivors.

In particular, the study, which assessed mortality at 15 years from diagnosis, looked at the effect of cancer treatment on the heart and lungs—two organs that suffer significant late effects from cancer treatment.

From 1970 to 1994, all measures of mortality dropped significantly over time, including all-cause mortality and death from a subsequent cancer or cardiac or pulmonary death. The results suggest that not only are patients living longer, but also are less likely to die of common long-term side effects of cancer treatments.

One of the most significant changes to childhood cancer treatments during this period was a reduction in radiation therapy. The study's results, the investigators said, provide evidence that these changes, as well as efforts to improve early detection of both side effects and secondary cancers, have been beneficial over the long term.

Dr Nekhlyudov: The current cohort of adult survivors of childhood cancer who come into primary care are those who were treated in the decades of more intense regimens. As a result, these survivors have many comorbid medical conditions and a lot of symptoms. Primary care providers don't know how to approach these patients, how to manage their symptoms, or how to evaluate the potential late effects.

This study provides a glimpse of hope for the future cohorts of cancer survivors. In the meantime, primary care providers should be aware that patients treated for cancer as children remain at risk for long-term complications and premature death. It is important that the PCP ask patients about their cancer and treatment. Specifically, did they get radiation and where, and did they get any drugs that may have potential late effects? If the patient doesn't know, the PCP can consult with the cancer center.

For example, many cancer centers now offer consultative visits for cancer survivors. The cancer center can obtain the medical records and develop a survivorship care plan, which will summarize the treatments received and outline a plan for follow-up. The current cohort of survivors should be receiving a survivorship care plan upon transition back into primary care.

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