Many primary care physicians – and even some oncologists – are unaware of common long-term side effects of four widely used breast and colorectal cancer drugs, a national survey by the National Cancer Institute reveals.

Only 6% of primary care physicians were able to identify the main long-term effects (LEs) of doxorubicin (Adriamycin), paclitaxel (Taxol), oxaliplatin (Eloxatin), and cyclophosphamide (Cytoxan), compared with 65% of oncologists surveyed.

The results are not surprising, but they underscore the need for ongoing education among all physicians who care for the more than 12 million cancer survivors in the United States, lead author Dr. Larissa Nekhlyudov said during a press briefing highlighting research to be presented at the upcoming annual meeting of the American Society of Clinical Oncology (ASCO).

"These findings emphasize that in the transition of patients from oncology to primary care settings, primary care providers should be informed about the late effects of cancer treatment so that they may be better prepared to recognize and address these among cancer survivors in their care," said Dr. Nekhlyudov, a primary care physician (PCP) with Harvard Medical School in Boston and Harvard Vanguard Medical Associates in Kenmore, Mass. "Whether this will be achieved with survivorship care plans needs to be evaluated."

The "Survey of Physician Attitudes Regarding the Care of Cancer Survivors" was launched by the National Cancer Institute in 2009, with one survey mailed to a nationally representative sample of 1,072 PCPs and the other to 1,130 medical oncologists who only cared for patients with colorectal or breast cancer.

When asked to report the five LEs they had observed and/or had seen reported in the literature for each of the four standard chemotherapy drugs, 95% of oncologists identified cardiac dysfunction as an LE of doxorubicin, compared with 55% of PCPs (P less than .0001), Dr. Nekhlyudov said.

Similarly, peripheral neuropathy was correctly identified as an LE of paclitaxel and of oxaliplatin by 97% of oncologists, but by only 27% and 22%, respectively, of PCPs (both P less than .0001).

The survey suggests, however, that some oncologists could also use additional continuing education. Premature menopause and secondary malignancies – two long-term effects associated with the alkylating agent cyclophosphamide – were identified by only 71% and 62% of oncologists, respectively, along with 15% and 17%, respectively, of PCPs.

Oncologists and PCPs mostly missed pulmonary fibrosis as a late effect for paclitaxel (5% and 6%, respectively; P = .42) or oxaliplatin (5% and. 9%, respectively; P = .0002). They did a little better in pointing out a possible association with cyclophosphamide (20.6% and 13%; P less than .0001), which has been noted in the literature, she observed.

Dr. Nekhlyudov suggested that the lack of awareness among oncologists is likely because much of the focus has been on the treatment of cancer, and only recently have physicians become aware of the importance of survivorship and the potential for late effects.

"While it is surprising that oncologists were not more aware of late effects, I think that as more and more attention is placed on cancer survivorship, oncologists will become more equipped with that information," she said.

ASCO president and press briefing comoderator Dr. Michael Link said the problem of survivorship has long been recognized in pediatric oncology, where patients frequently relocate, outgrow their pediatrician, or even deny they ever had cancer. Groups such as ASCO and the Institute of Medicine, most recently through its "Lost in Transition" report, have offered guidance for improving transitions among survivors, including the provision of a cancer care plan.

"I think the need for all of this has been highlighted in this abstract and certainly, it’s a shot across the bow with things that need to be done," he said.

In adjusted analyses, oncologists who were not board certified were less likely to identify the main LEs for all four drugs (odds ratio, 0.58).Oncologists were more likely to know their LEs if they spent 51%-90% of their time on patient care (OR, 1.87) or more than 90% of their time with patients (OR, 1.82). Age, sex, race, U.S. training, type of practice, and percentage of uninsured patients were not associated with LE awareness, Dr. Nekhlyudov said.

Previous results from the survey reported at last year’s ASCO annual meeting indicated that PCPs had low confidence in their knowledge of breast and colon cancer survivors, and reported low marks for their skills in caring for these patients. In addition, neither PCPs nor oncologists felt that a PCP-led model was ideal for survivorship care (J. Clin. Oncol. 2011;29[suppl.];abstract CRA9006).

Dr. Nekhlyudov will formally present her study at ASCO at 5:30 p.m. June 2. The abstract can be viewed at www.abstract.asco.org.

The authors reported no disclosures.

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