NSCLC: Long-Term Results With Proton Beam Therapy Plus Chemotherapy

Promising Long-Term Results With Proton Beam Therapy Plus Chemotherapy In NSCLC Patients
Five-year phase II results justify further investigation of concurrent proton beam therapy and chemotherapy in patients with inoperable non-small-cell lung cancer

Date: 26 Jul 2017
Author: By Shreeya Nanda, Senior medwireNews Reporter
Topic: Non-Small-Cell Lung Cancer, Locally Advanced / Surgery and/or Radiotherapy of Cancer

medwireNews: The final results of a phase II study show that a concurrent regimen of proton beam therapy (PBT) and chemotherapy is efficacious and has acceptable tolerability in the long-term among patients with unresectable stage III non-small-cell lung cancer (NSCLC).

This combined modality could be “an important option with which to definitively treat locally advanced NSCLC”, say Joe Chang, from the University of Texas MD Anderson Cancer Center in Houston, USA, and fellow researchers.

A total of 84 patients with stage IIIA or IIIB disease were enrolled in the study investigating the use of 74-Gy passively scattered PBT, which the investigators say “is an attractive option with which to reduce toxic effects of [chemoradiotherapy]”, alongside a regimen of carboplatin and paclitaxel.

After excluding participants who did not receive protocol-specific PBT, those with inappropriate staging and those lacking follow-up data, 64 patients were followed up for a median of 27.3 months. The median follow-up was 79.6 months for the 27% of study participants who were alive at the last follow-up.

As reported in JAMA Oncology, the 5-year overall and progression-free survival rates were 29% and 22%, respectively, with corresponding median times of 26.5 and 12.9 months. Treatment failures manifested more often as distant recurrences (48% of patients) than as local (16%) or regional (14%) relapses.

The incidences of acute adverse events occurring within 90 days of the last treatment and late adverse events occurring after the 90-day period were low and compared favourably with historical data using photon-based therapy, the study authors report.

Acute grade 2 and 3 oesophagitis was observed in 28% and 8% of study participants, respectively. The corresponding rates of late oesophagitis were 5% and 2%; there was also one case of late grade 4 oesophagitis.

Two percent of patients experienced acute grade 2 pneumonitis and there were no cases of grade 3 or 4 events, while the corresponding incidences of late pneumonitis were 16%, 12% and 0%.

There were no adverse events of grade 5 in either the acute or late setting.

In an accompanying editor’s note, Charles Thomas Jr, from Oregon Health Sciences University in Portland, USA, describes the study as “important” given that “well-designed, prospective clinical trials have lagged as the number of proton centers has increased.”

Looking to the future, he writes: “The current NRG/RTOG protocol 1308 will seek to clarify any survival benefit when comparing photon and proton thoracic radiotherapy atop a platinum-doublet chemotherapy backbone in a randomized clinical trial.

“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.”

References

Chang JY, Verma V, Li M, et al. Proton beam radiotherapy and concurrent chemotherapy for unresectable stage III non–small-cell lung cancer. Final results of a phase 2 study. JAMA Oncol; Advance online publication 20 July 2017. doi: 10.1001/jamaoncol.2017.2032

Thomas Jr CR. Potential of prospective particle therapy trials to increase the therapeutic ratio for locally advanced lung cancer. JAMA Oncol; Advance online publication 20 July 2017. doi: 10.1001/jamaoncol.2017.2165