Current controversies in the stage-specific multidisciplinary management of pancreatic cancer

Neoadjuvant therapy for resectable pancreatic cancer

The use of neoadjuvant therapies has played a major role for borderline resectable and locally advanced pancreatic cancers (PCs). For this group of patients, preoperative chemotherapy or chemoradiation has increased the likelihood of surgery with negative resection margins and overall survival. On the other hand, for patients with resectable PC, the main rationale for neoadjuvant therapy is that the overall survival with current strategies is unsatisfactory. There is a consensus that we need new treatments to improve the overall survival and quality of life of patients with PC. However, without strong scientific evidence supporting the theoretical advantages of neoadjuvant therapies, these potential benefits might turn out not to be worth the risk of tumors progression while waiting for surgery. The focus of this paper is to provide the readers an overview of the most recent evidence on this subject.

Outcomes for patients with locally advanced pancreatic adenocarcinoma treated with stereotactic body radiation therapy versus conventionally fractionated radiation

BACKGROUND

As systemic therapy has improved for locally advanced pancreatic cancer (LAPC), efforts to improve local control with optimal radiotherapy may be critical. Although conventionally fractionated radiation therapy (CFRT) has more recently shown a limited role in LAPC, stereotactic body radiation therapy (SBRT) is an emerging approach with promising results. With no studies to date comparing SBRT with CFRT for LAPC, this study used the National Cancer Data Base (NCDB) to evaluate these 2 modalities.

METHODS

With the NCDB, patients with American Joint Committee on Cancer cT2-4/N0-1/M0 adenocarcinoma of the pancreas diagnosed from 2004 to 2013 were analyzed. Radiation therapy delivered at ≤2 Gy was deemed CFRT, and radiation therapy delivered at ≥4 Gy per fraction was considered SBRT. Kaplan-Meier analysis, log-rank testing, and multivariate Cox proportional hazards regression were performed with overall survival (OS) as the primary outcome. Propensity score matching was used.

RESULTS

Among 8450 patients, 7819 (92.5%) were treated with CFRT, and 631 (7.5%) underwent SBRT. Receipt of SBRT was associated with superior OS in the multivariate analysis (hazard ratio, 0.84; 95% confidence interval, 0.75-0.93; P < .001). With propensity score matching, 988 patients in all were matched, with 494 patients in each cohort. Within the propensity-matched cohorts, the median OS (13.9 vs 11.6 months) and the 2-year OS rate (21.7% vs 16.5%) were significantly higher with SBRT versus CFRT (P = .0014).

CONCLUSIONS

In this retrospective review using a large national database, SBRT was associated with superior OS in comparison with CFRT for LAPC, and these findings remained significant in a propensity-matched analysis. Further prospective studies investigating these hypothesis-generating results are warranted. Cancer 2017;123:3486-93. © 2017 American Cancer Society.

Stereotactic body radiotherapy for the pancreas: a critical review for the medical oncologist

With recent advances in imaging modalities and radiation therapy, stereotactic body radiotherapy (SBRT) has allowed for the delivery of high doses of radiation with accuracy and precision. As such, SBRT has generated favorable results in the treatment of several cancers. Although the role of radiation has been controversial for the treatment of pancreatic ductal adenocarcinoma (PDAC) due to rather lackluster results in clinical trials, SBRT may offer improved outcomes, enhance the quality of life, and aid in palliative care settings for PDAC patients. This review delineates the role of SBRT in the treatment of PDAC, presents the defining principles of radiation biology and the radiation oncology work flow, and discusses the prospects of new treatment regimens involving tumor immunology and radiation therapy.

Radiosensitivity index predicts for survival with adjuvant radiation in resectable pancreatic cancer

BACKGROUND AND PURPOSE

Adjuvant radiation therapy for resectable pancreatic cancer remains controversial. Sub-populations of radiosensitive tumors might exist given the genetic heterogeneity of pancreatic cancers. We evaluated whether RSI is predictive of survival in pancreatic cancer treated with radiation.

MATERIALS AND METHODS

We identified 73 genomically-profiled pancreas cancer patients treated with upfront surgery between 2000 and 2011 (48 radiation, 25 no radiation). Briefly, RSI score is derived from the expression of 10 specific genes and a linear regression algorithm modeled on SF2 of 48 cancer cells. The primary endpoint was to assess the association of RSI with overall survival.

RESULTS

Median follow-up was 67months for surviving patients. On multivariate analysis, patients with radioresistant tumors had a trend toward worse survival (Hazard ratio [HR] 2.1 [95% CI 1.0-4.3], p=0.054). Among high-risk, irradiated patients (positive margins, positive lymph nodes, or a post-operative CA19-9 >90; n=31), radiosensitive patients had significantly improved survival compared with radioresistant patients (median 31.2 vs. 13.2months; HR 0.42 [0.19, 0.94], p=0.04). Among irradiated patients (n=48), low-risk patients lived longer than both high-risk patients with radiosensitive tumors and radioresistant tumors (HR 2.7 [1.0, 7.2], p=0.04 and HR 6.3 [2.3, 17.0], p<0.001, respectively).

CONCLUSIONS

Integrating RSI with standard high-risk variables has the potential to refine the classification of high-risk resected pancreatic cancer patients treated with radiation therapy.