Removal of the entire lobe of lung may offer patients with early-stage lung cancer better overall survival when compared with a partial resection. And stereotactic ablative radiotherapy (SABR) may offer the same survival benefit as a lobectomy for some patients, according to a study from MD Anderson Cancer Center.
The research is the largest population-based study to review modern treatment modalities for early-stage lung cancer and was published in JAMA Surgery.
According to the American Cancer Society, 224,210 people in the U.S. will be diagnosed with lung cancer in 2014, and more than 159,260 will die from the disease. And with the aging baby-boomer population colliding with spiral CT-screening’s acceptance as a screening tool for lung cancer, the number of cases diagnosed is expected to rise dramatically, says Shervin M. Shirvani, M.D., attending radiation oncologist at Banner MD Anderson Cancer Center in Arizona and an adjunct professor at MD Anderson.
The disease is typically a cancer of the elderly, and because of its association with smoking, patients often carry other comorbidities such as coronary artery disease and renal failure (COPD).
“Currently, lung cancer is one of the most common and fatal cancers, and for the foreseeable future it will be one of the major health epidemics our country faces. Yet we don’t have strong evidence-based guidelines for how to best treat the disease — especially when it’s discovered early,” said Shirvani, the study’s first author.
Three treatment options are widely available for patients with early-stage disease: lobectomy, or removal of the entire lobe of lung; sublobar resection, or removal of the part of the lung that contains the tumor; and SABR, a precise form of radiation therapy delivered over three to five sessions.
Several randomized trials to compare the three modalities have been attempted, but each has been set back by low accrual and lack of participation by patients and physicians, Shirvani explained.
“In the absence of clinical trials, it was important to analyze observational data from a very large database to compare these three modalities,” he said. “We wanted to compare lobectomy, the treatment generally thought to be the standard of care, to both the smaller surgery and stereotactic ablative radiotherapy, which does not carry surgical risk. We hoped this comparison would help us better understand which may be best for this elderly patient population with extensive concurrent illnesses.”
For the retrospective, population-based study, the researchers analyzed the Surveillance, Epidemiology and End Results (SEER) Medicare database to identify 9,093 patients treated for non-small cell lung cancer between 2003 and 2009. All received one of three treatment strategies: lobectomy (7,215 patients, or 79.%); sublobar resection (1,496 patients, or 16.5%); and SABR (382 patients, or 4.2%). Of note, says Shirvani, is that the study’s time period reflects the earliest adopters of SABR.
Adjusting for characteristics associated with the patient, the tumor, economic factors and other co-variables, the researchers found that the lobectomy was associated with better overall and lung cancer-specific survival, when compared to sublobar resection. This finding surprised the researchers.
“The assumption was the smaller surgery would be better than a whole lobectomy for an elderly patient with a number of comorbidities because there would be fewer surgical complications. Yet it appears that the ability to eradicate the cancer with the bigger surgery may be more important than minimizing surgical risk,” he explained.
When patients with similar baseline characteristics treated with lobectomy and SABR were compared, the two modalities were associated with similar overall and lung cancer-specific survival. This suggests that SABR is a very promising alternative to surgery for patients with very advanced age and multiple medical problems, features commonly observed in the matched populations.
While observational, Benjamin Smith, M.D., associate professor in Radiation Oncology at MD Anderson and the study’s corresponding author, hopes the physicians will begin to exercise caution with the belief that a smaller surgery is better-suited for this patient population.
“Clearly, the incidence of early-stage lung cancer will increase dramatically in the next few years, and we need to be prepared to treat patients in the right way — balancing the effectiveness versus risk of treatment in an elderly population,” Smith said.
“Observational studies like ours give us insight into what the right treatment strategy should be and hopefully will encourage both physicians and patients that prospective clinical trials are worth pursuing,” he continued.
In addition to Shirvani and Smith, other MD Anderson researchers on the study include Thomas A. Buchholz, M.D., Executive Vice President and Physician-In-Chief; Stephen G. Swisher, M.D., professor and Division Head of Surgery; Joe Y. Chang, M.D., Ph.D., professor in Radiation Oncology; James Welsh, M.D., associate professor in Radiation Oncology; and Jing Jiang, Health Services Research. Anna Likhacheva, M.D., from Banner MD Anderson’s Department of Radiation Oncology, is also an author.