This article is more than 5 years old. Information may no longer be current.
Proton beam therapy shows promise for non-small cell lung cancer
Click Here to Manage Email Alerts
Proton beam radiotherapy with concurrent chemoradiotherapy appeared safe and effective among patients with advanced non-small cell lung cancer, according to results of a phase 2 prospective study.
“This is first and only study with 5 years survival of concurrent chemotherapy and proton therapy in inoperable stage III NSCLC,” Joe Y. Chang, MD, PhD, professor of radiation oncology at The University of Texas MD Anderson Cancer Center, told HemOnc Today. “[Proton beam radiotherapy] had a great potential to treat lung cancer. However, the technology is still improving and better result will be achieved in near future.”
Concurrent chemoradiotherapy is the standard of care for unresectable locally advanced disease; however, intolerance due to comorbidities and lack of benefit are barriers that persist.
Previous research showed an association between proton beam therapy — also called proton radiotherapy — and better health outcomes, as well as fewer adverse events than 3-dimensional conformal radiotherapy and intensity-modulated radiotherapy.
Chang and colleagues evaluated late complications, adverse events and survival outcomes associated with proton beam therapy in adults with NSCLC.
The study included 64 patients (34% women; median age, 70 years) with stage IIIA (n = 30) or stage IIIB disease (n = 34). Each patient underwent concurrent chemoradiotherapy with carboplatin-paclitaxel and scattered proton beam therapy at 74 Gy. None of the patients required proton beam therapy treatment adjustment.
Patients were enrolled in 2006, at a time when PET image quality was poor, Chang said. Therefore, some of the patients may have been understaged.
“We have more advanced proton therapy now with intensity-modulated proton therapy to paint the dose as we desired based on tumor location and sparing nearby critical normal organs,” Chang added.
The main outcomes measured included OS on Kaplan-Meier analysis, PFS, actuarial distant metastases and locoregional recurrence.
Median follow-up was 27.3 months (range, 2.7-111.5) for all patients.
At the last follow-up, 17 patients remained alive. Median OS was 26.5 months. Twenty-nine percent (95% CI, 18-41) of patients achieved 5-year OS and 22% (95% CI, 12-32) achieved 5-year PFS.
The 5-year rate for any recurrence was 64% (95% CI, 51-76). Researchers reported a higher 5-year actuarial distant metastasis rate (54%; 95% CI, 40-68) than locoregional recurrence rate (28%; 95% CI, 18-43).
Treatment failures more commonly occurred among patients with largely distant tumors (n = 31), low rates of crude local recurrences (n = 10) and regional recurrences (n = 9).
Multivariate analysis showed four parameters independently correlated with poor OS, including Karnofsky performance status 70 to 80 compared with 90 to 100 (HR = 2.48); stage IIIB compared with stage IIIA (HR = 2.04); tumor location in left lung or right lower lobe compared with right middle or upper right lobe (HR = 1.9); and pretreatment tumor size greater than 7 cm compared with less than 7cm (HR = 2.39).
One patient experienced acute grade 2 pneumonitis and two developed grade 2 bronchial strictures.
Late toxic effects appeared uncommon and included grade 2 esophageal stricture and grade 4 esophagitis (n = 1 for each). Late grade 2 pneumonitis occurred in 10 patients and late grade 3 occurred in eight patients. One patient developed a grade 4 bronchial fistula.
“It is anticipated that particle therapy may have other unique biological effects that may work synergistically with biological therapies such as immunotherapy,” Chang said.
Future studies are underway to determine any difference in survival benefit between photon and proton radiotherapy, although “real dedication” is needed to conduct a prospective study of particle therapy, Charles R. Thomas Jr., MD, professor and chair of the department of radiation medicine at Oregon Health Sciences University, wrote in a related editor’s note.
“The current NRG/RTOG protocol 1308 will seek to clarify any survival benefit ... [and] if the results are encouraging, next-generation particle therapy trials for locally advanced non-small cell lung cancer may seek to incorporate adaptive planning and delivery along with more advanced image guidance and proton beam modulation,” Thomas Jr. wrote. “At the end of the day, patients, clinicians, payers, vendors and policymakers will anticipate the design, execution and reporting of ongoing and future well-designed clinical trials testing particle therapy.” – by Melinda Stevens
For more information:
Joy Y. Chang, MD, PhD, can be reached at Department of Radiation Oncology, Unit 97, University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030.
Disclosure: Chang reports he receives research funding and honoraria from Varian Medical Systems; and is a shareholder of Global Oncology One outside of the study. The other researchers and Thomas report no relevant financial disclosures.
Click Here to Manage Email Alerts