Predicting Survival by PET/CT Response to Presurgical Chemoradiation in GE Cancer
Predicting Survival by PET/CT Response to Presurgical Chemoradiation in GE Cancer
Abstract & Commentary
By William B. Ershler, MD
Synopsis: The authors assessed 151 consecutive patients with gastroesophageal adenocarcinoma who had chemoradiation and surgery. Baseline and post-chemoradiation positron emission tomography changes were correlated with overall survival and the degree of pathologic response in the resected specimen. Their results showed that the degree of changes used as continuous variable produce the best estimate for survival compared to traditional dichotomized percent decrease.
Source: Javeri H, et al. The higher the decrease in the standardized uptake value of positron emission tomography after chemoradiation the better the survival of patients with gastroesophageal adenocarcinoma. Cancer. 2009;115:5184-5192.
Patients with localized esophageal cancer are often treated with preoperative-combined chemotherapy and radiation. This therapy, however, is not uniformly successful and is associated with considerable morbidity and mortality. Thus, a method that would predict event-free and overall survival would be of value. In this regard, positron emission tomography (PET) has been shown to offer predictive value for patients with esophageal cancer.1-4 Furthermore, a decrease in metabolic activity, as measured by standardized uptake value (SUV) on PET/computed tomography (CT), as a result of therapy, has been shown to be of prognostic importance.3-7 In the current report, Javeri et al from MD Anderson Cancer Center have retrospectively reviewed clinically important outcomes (pathologic response, overall survival) in the context of pre-surgical chemoradiation treatment-induced percentage SUV decrease.
In addition to an analysis of dichotomized data (i.e., SUV at baseline vs. SUV just prior to surgery), treatment-induced change in SUV also was analyzed as a continuous variable.
For this, the authors assessed 151 consecutive patients with gastroesophageal adenocarcinoma who had chemoradiation and surgery. Chemotherapy and surgical approaches were variable, but all were treated with curative intent. All patients received fluorouracil concurrently with radiation in combination with either a platinum compound or taxane or both a platinum compound and taxane. Radiation was delivered in 180cGy daily fractions to a total dose of either 45 or 50.4 Gy. Surgical procedures included three field esophagectomy, transhiatal esophagectomy, transthoracic esophagectomy, or minimally-invasive esophagectomy. The resected surgical specimen was examined to determine the degree of pathologic response. Baseline and post-chemoradiation PET/computed tomography imaging was performed.
By using the log-rank and Cox proportional hazards models, it was shown that a > 52% SUV decrease was associated with a longer OS (log-rank test, p = .023). The univariate Cox proportional hazards model indicated that greater percentage SUV decrease (as a continuous variable) was associated with a lower risk of death (hazard ratio [HR], 0.99; p = .01). Pathologic response (< 50% residual cancer) was associated with longer OS (p = .003). Patients with a less than 50% reduction in tumor volume tended to have a higher risk of death than those with 0-50% residual cancer (HR, 2.12; p = .099). In the multivariate model, the percentage SUV decrease (as a continuous variable) was the only significant prognosticator of OS (p = .01). However, although there was an apparent trend, the percentage SUV decrease was not significantly associated with pathologic complete response (univariate odds ratio [OR], 1.01; p = .06 and multivariate OR, 1.03; p = .07).
Commentary
Although this and other studies show that PET/CT changes do not correlate with pathologic complete response, nevertheless the percentage SUV change after chemoradiation, when used as a continuous variable, is an independent prognosticator of OS. Thus, the greater the decline in SUV after chemoradiation for patients with gastroesophageal adenocarcinoma, the longer the OS. This advance in our understanding should be confirmed by additional study from other institutions or as an outcome measure in multisite trials. If confirmed, the treatment-associated change in SUV might prove useful in the assessment of different pre-surgical approaches in future clinical trials as well as an indicator to clinicians on which patients may require aggressive post-surgical management.
References
1. Hong D, et al. Value of baseline positron emission tomography for predicting overall survival in patient with nonmetastatic esophageal or gastroesophageal junction carcinoma. Cancer. 2005;104:1620-1626.
2. Lordick F, et al. PET to assess early metabolic response and to guide treatment of adenocarcinoma of the oesophagogastric junction: the MUNICON phase II trial. Lancet Oncol. 2007;8:797-805.
3. Swisher SG, et al. Utility of PET, CT, and EUS to identify pathologic responders in esophageal cancer. Ann Thorac Surg. 2004;78:1152-1160.
4. Ott K, et al. Metabolic imaging predicts response, survival, and recurrence in adenocarcinomas of the esophagogastric junction. J Clin Oncol. 2006;24:4692-4698.
5. Ott K, et al. Fluorodeoxyglucose-positron emission tomography in adenocarcinomas of the distal esophagus and cardia. World J Surg. 2003;27:1035-1039.
6. Swisher SG, et al. 2-Fluoro-2-deoxy-D-glucose positron emission tomography imaging is predictive of pathologic response and survival after preoperative chemoradiation in patients with esophageal carcinoma. Cancer. 2004;101:1776-1785.
7. Brucher BL, et al. Neoadjuvant therapy of esophageal squamous cell carcinoma: Response evaluation by positron emission tomography. Ann Surg. 2001;233: 300-309.
The authors assessed 151 consecutive patients with gastroesophageal adenocarcinoma who had chemoradiation and surgery.Subscribe Now for Access
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