Small cell lung cancer (SCLC) patients with extensive-stage disease can achieve long-term survival, particularly if they are given comprehensive chemotherapy with a cisplatin-based regimen, a retrospective data analysis suggests.
In a poster presented at the 17th World Conference on Lung Cancer (WCLC), researchers showed that patients who received chest radiation and prophylactic cranial irradiation along with a mean of five chemotherapy cycles could achieve a median survival of more than 5 years.
However, it was notable that few baseline characteristics could be used to determine whether or not SCLC patients with extensive-stage disease would achieve exceptional survival, rather than only favorable performance status.
"Although the chance of curing extensive-stage SCLC is small, long-term survival can be achieved," say the researchers. The lead author was Kunlatida Maneenil, MD, Oncology Unit, Department of Medicine, Rajavithi Hospital, College of Medicine, Rangsit University, Bangkok, Thailand, who collaborated with colleagues in China and from the Mayo Clinic in the United States.
"This pilot study supports the importance of good performance status and the achievement of a response to cisplatin-based chemotherapy to achieve long-term survival," they add.
Retrospective Review of Data
SCLC accounts for about 13% of all new lung cancer diagnoses worldwide, with approximately 180,000 cases per year. It is the seventh most common cause of cancer-related death in the United States.
Although it is known that the majority of patients present with extensive-stage disease and have a poor prognosis ― the median survival is 8 to 13 months, and the 2-year survival rate is only 5% ― there have been reports of long-term survival in patients with the disease.
In their poster presentation, Dr Maneenil and colleagues report the results of a retrospective review of data collected at the Mayo Clinic, in Rochester, Minnesota, between 1997 and 2007. The researchers examined all extensive-stage SCLC cases that were diagnosed and followed at the clinic. They identified 36 patients who were exceptional survivors, and a further 144 patients who were expected survivors (defined as those who died less than 12 months after diagnosis).
In terms of baseline characteristics, there was a significant difference with respect to sex. Women accounted for 63.9% of the exceptional survivors compared to 39.6% of the expected survivors (P = .0087).
There was also a significant difference in the proportion of patients who had good performance status (Eastern Cooperative Oncology Group performance status score of 0-1 at baseline), at 97.2% of exceptional survivors vs 77.6% of expected survivors (P = .0066).
However, there were no significant differences between the two groups with respect to race, smoking status, number of pack-years, prior malignancies, the presence of chronic obstructive pulmonary disease, the presence of paraneoplastic syndrome, or TNM stage.
Exceptional SCLC survivors were more likely than expected survivors to have undergone chemotherapy (100.0% vs 80.6%; P = .0015), chest radiation (58.3% vs 19.4%; P = .0075), or prophylactic cranial irradiation (19.4% vs 6.9%; P = .0345).
Such patients were also less likely than expected survivors to have received a carboplatin/etoposide chemotherapy regimen (40.0% vs 61.6%) and were more likely to have received a cisplatin/other regimen (60.0% vs 38.4%; P = .0248 overall).
The mean number of chemotherapy cycles was also greater for exceptional than expected survivors, at 5 ± 1.2 vs 3.6 ± 1.7 (P < .0001).
The median overall survival among SCLC patients in the exceptional survival group was 5.4 years. For these patients, the overall response rate to first-line chemotherapy was 91.4% vs 54.0% for expected survivors (P < .0001).
This difference in response rates was underpinned by a large difference in the number of patients who achieved a complete response to therapy, at 37.1% for exceptional vs 2.7% for expected survivors. Rates of progressive disease were 5.7% and 30.4%, respectively.
On the basis of these findings, the team concluded, "Addition of thoracic radiotherapy and prophylactic cranial irradiation are beneficial to prolong life of extensive-stage SCLC patients."
No funding for the study was declared. The researches have disclosed no relevant financial relationships.
17th World Conference on Lung Cancer (WCLC). Poster P1.07-045, presented December 5, 2016.