SAN FRANCISCO ― Patients with advanced small-cell lung cancer (SCLC) ― a disease associated with a notoriously poor prognosis ― had improved long-term survival when radiation therapy to the chest was added to standard treatment, according to a phase 3, randomized clinical trial presented here at the American Society for Radiation Oncology (ASTRO) 56th Annual Meeting.
At 2 years, the rate of overall survival was 13% in the group of patients receiving thoracic radiotherapy vs 3% for those who did not undergo radiotherapy (P = .004).
All of the 495 study participants had first been treated with chemotherapy (platinum etoposide) and had responded. They all had also undergone prophylactic intracranial radiation, which has been proven in earlier studies to improve survival in this setting.
"Thoracic radiotherapy should be considered for patients with extensive stage small-cell lung cancer who have responded to chemotherapy," write the authors, led by Ben Slotman, MD, professor of radiation oncology, VU University Medical Center, Amsterdam, the Netherlands.
Their study was simultaneously published online in the Lanceton September 14.
This approach is not for every eligible patient, said Jan van Meerbeeck, MD, of Ghent and Antwrep University in Belgium, and David Ball, MD, of the University of Melbourne in Australia, in an editorial that accompanies the study.
They cite an example of an unsuitable patient. "Would thoracic radiotherapy be appropriate in a [chemotherapy] responder who has large volume liver metastases and minimal intrathoracic disease burden?," the pair ask rhetorically.
Nevertheless, the editorialists are enthusiastic about the results, in part because many centers could undertake the treatment, at minimal cost.
"Refreshingly, the radiotherapy in Slotman and colleagues' study was not technically complex and it would be easy to provide at low cost in even the most modestly resourced radiotherapy departments," they write.
The thoracic radiotherapy (30 Gy in 10 fractions) was delivered with a linear accelerator; both 2D and 3D planning techniques were allowed. Treatment started 6 to 7 weeks after chemotherapy.
Adding radiation to the treatment regimen significantly reduced cancer recurrence in the chest, by almost 50%.
Specifically, intrathoracic progression occurred in 108 (43.7%) in the thoracic radiotherapy group vs 198 (79.8%) in the control group (P < .0001).
The idea to add radiation to the chest was prompted by the observation that "most patients" have residual intrathoracic disease after chemotherapy, the authors write in their meeting abstract.
Any treatment strategy that might improve survival should be tried, they suggest.
SCLC accounts for only 13% of all lung cancers, but the majority of patients present with extensive disease, write the authors. The disease is aggressive; 2-year survival is less than 5%, they also state.
Patients should embrace the results and the treatment, said Dr Slotman.
"I do expect that most patients will accept this treatment. The treatment...offers the patient a significantly lower risk of progression of the lung tumor and a significant improvement in survival. If they get prophylactic intracranial radiation as well, it can easily be combined with it without extra hospital visits," he told Medscape Medical News at ASTRO.
Not Toxic
Thoracic radiotherapy was very well tolerated in the new trial, which involved 42 centers in the Netherlands, the United Kingdom, Norway, and Belgium.
The most common grade 3 or higher toxic effects for the thoracic radiotherapy group vs the control participants were fatigue (4.5% vs 3.2%) and dyspnea (1.2% vs 1.6%).
Compliance was also high, with 95% of patients completing the protocol without disruption. The mean interval between diagnosis and randomization was 17 weeks. Median follow-up was 24 months.
Notably, overall survival did not differ between the 2 groups at 1 year; thus, it took a longer period for the treatment benefit to emerge.
Dr. Slotman explained why thoracic radiotherapy has not been used in this setting routinely in the past.
"Although most SCLC patients have persistent tumors within the chest after chemotherapy, at present, local thoracic radiotherapy is not generally given because of the spread of disease outside the thorax, and is reserved for palliation of symptoms," he said in a press statement.
But the new results provide evidence that thoracic radiotherapy has a number of benefits.
Progression-free survival was also significantly better among the patients receiving thoracic radiotherapy vs control participants (24% vs 7%; P = .001).
Even more radiotherapy might benefit these patients, said Dr. Slotman.
"While local control of the disease was good, the majority of patients still had disease progression outside the thorax and brain, indicating that additional radiotherapy should be investigated at sites of extrathoracic disease as well," he said.
The study has a significant shortcoming, say the editorialists. There are no patient-reported outcomes. Hence, quality of life is not assessed.
The study authors agree. If future studies use more toxic radiotherapy regimens, then patient-reported outcomes will be even more important, they state.
The study was funded by the Dutch Cancer Society (CKTO), the Dutch Lung Cancer Research Group, Cancer Research UK, the Academic Health Science Centre Trials Coordination Unit, and the UK National Cancer Research Network. Dr. Slotman has financial ties to Varian Systems and BrainLab.
American Society for Radiation Oncology (ASTRO) 56th Annual Meeting: Abstract CT-05. Presented September 14, 2014.
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου