Higher-Dose Radiotherapy Ups Survival in Pancreatic Cancer

Roxanne Nelson, BSN, RN

May 15, 2017

Radiotherapy can increase survival in early pancreatic cancer — but the catch is that the dose needs to be high enough to have an effect.

The results of a new study found that the higher the dose of chemoradiation, the higher the benefit. For example, patients who received the lowest dose of <45 Gy had an overall survival of 13 months, whereas survival more than doubled to 28 months for who received radiation doses of ≥55 Gy.

The new findings were presented at the European Society for Radiotherapy & Oncology (ESTRO 2017).

"Previous research has not shown a benefit for treating pancreatic cancer with radiotherapy, suggesting that these tumors are somehow resistant to radiation, but this study suggests the situation is more nuanced," said lead author Alessio Morganti, MD, head of the radiation oncology center at Sant'Orsola-Malpighi University and Hospital in Bologna, Italy.

We have found that the higher the dose, the longer the patient is likely to survive. Dr Alessio Morganti

"We have found that the higher the dose, the longer the patient is likely to survive," explained Dr Morganti.

"The pattern of increasing survival in this study suggests that tumors of the pancreas are not resistant to radiation, they just need to be tackled with an adequate dose," he added.

Higher Dose, Longer Survival

The multicenter, retrospective analysis included 514 patients with early-stage pancreatic adenocarcinoma (T1-3, N0-1, M0) who underwent surgical resection with macroscopically negative margins (R0-1) and who received radiatiotherapy as part of the regimen.

The cohort was stratified into four groups according to the dose of radiation: group 1, <45 Gy; group 2, ≥45 Gy and <50 Gy; group 3, ≥ 50 Gy and <55 Gy; and group 4, ≥55 Gy.

In addition, 141 patients received adjuvant chemotherapy.

On univariate analysis, poorer overall survival was associated with higher Ca19.9 levels (> 90 U/ml; P < .001), higher tumor grade (G3-4, P = .004), R1 resection (P = .004), higher pT stage (pT3-4, P = .002), and positive nodes (P < .001).

Higher doses of chemoradiation were significantly associated with superior overall survival. The median overall survival in group 1 was 12 months; group 2, 21.0 months; group 3, 22.0 months; and group 2, 28.0 months (P = .004).

Multivariate analysis confirmed the significant impact of receiving radiatotherapy at a higher dose (hazard ratio, 0.46; P = .005).

"Radiotherapy has benefitted from a number of technological improvements over recent years, and it is becoming easier to give higher doses that are targeted to the tumor area," said Dr Morganti. "This study suggests radiotherapy should be considered for patients with early-stage pancreatic cancer."

He also pointed out that it may be worthwhile to investigate whether current radiotherapy techniques could benefit patients with more advanced disease. His team is currently involved in a study of high-dose radiotherapy in the neoadjuvant setting.

"This is an interesting study which raises questions about the role that radiotherapy could play in extending the lives of people diagnosed with pancreatic cancer," commented Yolande Lievens, MD, president of ESTRO and head of the Department of Radiation Oncology at Ghent University Hospital, Belgium.

"In this grim disease, radiotherapy has not been shown to have an impact on survival, but the current study suggests the doses previously tested may have been too low to do so," she said. "Radiotherapy has evolved and improved considerably over recent years, allowing us to deliver higher doses without increasing side effects, and for a cancer with such poor survival rates, all promising new options should be explored."

The study received no external funding.

European Society for Radiotherapy & Oncology (ESTRO 2017). Abstract OC-0426, presented May 8, 2017.

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