For patients with advanced small cell lung cancer, chest radiation therapy in combination with conventional treatment may significantly increase long-term survival and reduce recurrence of the disease. This is according to a new study published in The Lancet.
Small cell lung cancer (SCLC) accounts for around 10-15% of all lung cancer cases. It is almost always caused by smoking and tends to spread rapidly to other parts of the body, meaning it is often diagnosed in its advanced stages.
According to the research team, led by Ben Slotman, professor of radiation oncology at the VU University Medical Center in Amsterdam, the Netherlands, standard treatment for SCLC involves chemotherapy followed by prophylactic cranial radiotherapy – radiation to the head and neck to stop the cancer spreading to the brain.
But Prof. Slotman notes that these patients have a poor survival rate – only 5% live 2 years or more. In addition, he says the chance of cancer recurrence and the likelihood of it spreading to other areas of the body remains high among this group.
Chest radiation therapy, also referred to as thoracic radiotherapy, is not usually offered to SCLC patients following chemotherapy, according to the team, as the cancer has already spread outside the thorax.
But the researchers wanted to see how thoracic radiotherapy, in combination with standard treatment for SCLC, would affect patients’ survival and likelihood of cancer recurrence.
The team conducted a phase 3 clinical trial involving 498 adults with advanced SCLC from 42 hospitals, of which 16 were in the Netherlands, 22 were in the UK, three were in Norway and one was in Belgium.
The patients, who had already responded to first-line chemotherapy for the cancer, were randomized to receive one of two treatments – prophylactic cranial radiotherapy alone or prophylactic cranial radiotherapy plus thoracic radiotherapy, administered over 2 weeks. They were followed-up for an average of 2 years.
After 1 year, patient survival was similar between both treatment groups. However, after 2 years, the team found that 13% of patients treated with prophylactic cranial radiotherapy plus thoracic radiotherapy were alive, compared with only 3% of patients who were treated with prophylactic cranial radiotherapy alone.
Furthermore, of the patients who received prophylactic cranial radiotherapy plus thoracic radiotherapy, 20% had cancer recurrence in the chest, compared with 46% who received prophylactic cranial radiotherapy alone.
The researchers say thoracic radiotherapy was well tolerated by patients, with no severe acute or late toxic side effects. They say the most common side effects grade 3 or higher were fatigue and shortness of breath.
Commenting on the findings, the researchers say:
“Our results show that thoracic radiotherapy improves long-term survival. Therefore, thoracic radiotherapy should be considered for patients with extensive stage small cell lung cancer who have responded to chemotherapy.”
Prof. Slotman adds, however, that patients still experienced disease progression outside the chest and brain after thoracic radiotherapy. He says this suggests such treatment should be investigated for use on areas of the body other than the thorax.
In an editorial linked to the study, Jan P van Meerbeeck, of Ghent and Antwerp University, Belgium, and David Ball, of the University of Melbourne, Australia, note that thoracic radiotherapy is not a technically complex procedure and would be easy to provide at low cost, even in radiotherapy departments with limited resources.
However, they point out that the initial aim of this study was to show that thoracic radiotherapy would prolong survival by more than 10% in the first year, compared with those who did not receive the treatment – something the study failed to do. But they note the delayed benefit is consistent with another study investigating thoracic radiotherapy for the treatment of SCLC.
Medical News Today recently reported on a study from the National Cancer Institute revealing that lung cancer rates in the US are declining.