HOUSTON – As survival grows for lung cancer patients, more are presenting with multiple primary lung cancers (MPLCs). Some are diagnosed with two simultaneous primary cancers (synchronous), while others develop a second lesion after treatment of their initial disease (metachronous).
The authors of a new study in Cureus report that the incidence of MPLCs now ranges from 3.7% to 8%, often related to tobacco use.1
The question raised by researchers from the Michael E. DeBakey VAMC and the Baylor College of Medicine is how best to treat those patients. “Although open surgery remains a treatment mainstay for patients with stage I-II non-small-cell lung cancer (NSCLC), stereotactic body radiation therapy (SBRT) is an acceptable alternative for patients who are medically unfit for or who refuse surgery,” they pointed out.
The study team retrospectively examined the outcomes among 38 patients with a total of 80 early-stage MPLCs treated at a single institution with SBRT. To do that, they reviewed retrospectively patients receiving SBRT for MPLC between June 2011 and March 2020, as well as the imaging, and pathology related to the procedure. They added that dose and fractionation varied, although the most common prescriptions were 50 Gy/5 fractions, 56 Gy/4 fractions, and 55 Gy/5 fractions.
The study’s median follow-up was 25.9 months, with local control (LC) rates calculated per lesion to be 98.6%, 93.3%, and 88.2% at one, two, and three years.
Results indicated that median overall survival (OS) was 43.5 months; 83.6%, 67.8%, and 52.3% at one, two, and three years, respectively. The researchers advised that 62 of the 80 (77.5%) treated lesions were not associated with any subsequent acute or late toxicity. Of the 18 (22.5%) lesions associated with toxicity, nine were acute and nine were late events. All toxicity was either grade 1 (13 of 18) or grade 2 (five of 18), they said.
“SBRT for early-stage MPLC achieves high control rates with limited toxicity,” the authors concluded. “MPLC patients deemed unfit for open surgical management should be considered for definitive SBRT.”
The study pointed out that surgical resection is most common for the treatment of stage I-II NSCLC, with SBRT used only as an alternative for patients who are medically unfit or who refuse surgery.
The authors noted that while a previous study found an association between synchronous disease presentation and worse progression-free survival and overall survival, theorizing that these patients were presenting with early metastatic disease, this study did not find that. “Patients with synchronous presentation demonstrated superior OS on univariate analysis, perhaps suggesting that these patients presented with true MPLCs while the metachronous cohort in fact included patients with early metastatic disease,” they wrote. “This is bolstered by the fact that 21 of 22 of patients with synchronous disease underwent nodal staging via EBUS, while nodal staging numbers for the metachronous cohort were not as impressive.”
Stating that their study was one of the largest reported institutional experiences of lung SBRT for treatment-naïve, non-metastatic MPLCs, the researchers said “SBRT treatment for early-stage MPLC can achieve both high rates of tumor control and acceptable survival rates. It accomplishes these key goals with limited toxicity, notably no grade ≥≥ 3 toxicity. All patients deemed unfit for surgical management of MPLC should be considered for definitive SBRT.”
- Choi G, Chen G, Mai W, et al. (July 03, 2023) Multiple Primary Lung Cancers: Treatment Outcomes After Stereotactic Body Radiotherapy (SBRT). Cureus 15(7): e41319. doi:10.7759/cureus.41319