Practice Update: Oncology

CONFERENCE COVERAGE 14

Drugs that boost white blood cells prove safe during chemoradiotherapy of small-cell lung cancer

White blood cell-boosting drugs have proven safe during concurrent chemoradiotherapy of small-cell lung cancer, report late- breaking results of a subanalysis of the phase 3 Concurrent ONce-daily VErsus twice-daily RadioTherapy (CONVERT) trial. F abio Gomes, MD, of the Christie National Health Service Foundation Trust, Manchester, UK, explained “Opti-

He added, “The findings should give clini- cians the confidence to use granulocyte colony-stimulating factor when needed in this context. A complete analysis to be pub- lished later this year may hopefully help change current guidelines.” Stefan Zimmermann, MD, of the Hôpi- tal Cantonal, Fribourg, Switzerland, said, “Oncologists need granulocyte colony-stimulating factor to mitigate neutro- penia and increase chemotherapy delivery and compliance, but also want to see that the benefits of timely concurrent therapy outweigh the risks of toxicity.” He concluded, “In this analysis, the use of granulocyte colony-stimulating factor did not raise risk of pneumonitis, but the incidence of severe thrombocytopenia is a concern. The use of granulocyte colo- ny-stimulating factor was not detrimental to progression-free or overall survival. He continued, “We can conclude that pri- mary or secondary prophylaxis of febrile neutropenia with granulocyte colony-stim- ulating factor is justified, but patients at higher risk of thrombocytopenia should be treated with caution.”

during the treatment. For the analysis pre- sented at ELCC, toxicities and outcomes were compared between patients who received granulocyte colony-stimulating factor during concurrent chemoradiother- apy and those who did not. They confirmed that the chance of severe thrombocytopenia or anemia during treat- ment nearly doubled in patients given granulocyte colony-stimulating factor to around 30% and 20%, respectively. These incidences were lower than previous reports. Significantly higher use of further support- ive measures such as platelet and blood transfusions followed. No difference in the incidence of pulmonary complications or survival was observed. Dr Gomes said, “Granulocyte colony-stimu- lating factor exerted no significant negative impact on patient outcomes, a comforting result. Higher hematological toxicity was balanced by appropriate supportive care throughout treatment.” He concluded, “The use of granulocyte colony-stimulating factor during thoracic radiotherapy is safe and supports the full planned course of concurrent chemoradio- therapy to achieve the best possible benefit.”

mal treatment for limited-stage small-cell lung cancer is concurrent chemoradiother- apy. The efficacy of this intensive treatment is balanced by more toxicity, mainly hemato- logical but also esophageal and pulmonary. This is not a treatment for every patient and many will struggle to stay on track with the planned treatment.” Granulocyte colony-stimulating factors are commonly used supportively to boost the survival, proliferation and differentiation of neutrophils. The expected neutropenia is less severe and patients recover more quickly, reducing their risk for infectious complications. Its use during concurrent chemoradiother- apy in small-cell lung cancer is controversial, however, and the American Society of Clin- ical Oncology (ASCO) recommends against its routine use. The controversy is based on results of a randomized trial of 215 patients performed between 1989 and 1991. A signif- icant increase in severe thrombocytopenia, severe anemia, pulmonary complications, and toxic deaths was observed when granulocyte-macrophage colony-stimulat- ing factors were used during concurrent chemoradiotherapy. Dr Gomes said, “Two major changes have occurred since this trial was published in 1995 that may affect the safety of colo- ny-stimulating factors in this context. First, the trial evaluated granulocyte-macro- phage colony-stimulating factors, which act on more than one blood cell lineage and are not used commonly.” He continued, “Instead, we use granulo- cyte colony-stimulating factors, which are more specific and aim for neutrophil lin- eage only. Second, modern radiotherapy techniques have evolved significantly since then, are more precise, and reduce the risks of toxicity.” CONVERT randomized 547 patients with limited-stage small-cell lung cancer for concurrent chemoradiotherapy to once- or twice-daily radiotherapy. No difference in overall survival was observed between the two groups. The protocol allowed the use of granulo- cyte colony-stimulating factors, and around 40% of patients received one at some point

PracticeUpdate Editorial Team

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