Retrospective assessment of patterns of recurrence relative to radiotherapy volumes for adjuvant conformal chemoradiotherapy in gastric cancer

Abstract

Background Since the Intergroup 0116 study was published in 2000, adjuvant postoperative chemoradiotherapy using CT-planned and 3D conformal/intensity-modulated radiotherapy has been offered routinely to fit patients with resected gastric cancer at Princess Margaret Hospital .The objective of this study was to analyze patterns of disease recurrence with respect to the radiotherapy volumes. Methods For the date and site (local, locoregional, or distant) of the first recurrence, medical records were reviewed for all patients treated at Princess Margaret Hospital with adjuvant chemoradiotherapy for resected gastric adenocarcinoma (January 1, 2000 to November 30, 2009). Patients whose recurrences were limited to local and/or regional sites were selected for further analysis. Available diagnostic imaging of the recurrence site was registered to the original planning radiotherapy dataset for contouring. If necessary to respect changes in anatomy, the contour was translocated on the basis of anatomic descriptors. The center of mass for each recurrence was identified as a point and its location was categorized according to the isodose encompassing it; in field (90 % or more), marginal (50-89 %), or out of field (less than 50 %). Results Of all 197 patients, 14 (7 %) had isolated locoregional failure, constituting 20 % of all 71 patients with a recurrence. Successful fusions were feasible in five cases. Of these recurrences, four were in field and one was marginal. In a further four cases, visual inspection was used, showing one in-field recurrence, one marginal recurrence, and two out-of-field recurrences. In five patients, either a useable original dataset or diagnostic imaging of the recurrence was not available. Conclusions The rates of isolated local/locoregional tumor recurrence in this study were low. Of the small number of recurrences available for analysis, most (five of nine) were in field. Further studies involving a larger cohort of patients might allow a more meaningful analysis of trends in the recurrence site with evolving radiotherapy techniques.

Adjuvant Chemotherapy Versus Adjuvant Chemoradiation (CRT) for Gastric Cancer: 16 Years of Local Experience

“…Our data on pattern of failure echoed the findings from other studies that the vast majority (80-90%) of recurrences involved distant metastases (either alone or synchronously with locoregional recurrence). Among these, the majority of failure occurs in the peritoneum [23,24]. Locoregional recurrences were less common in both of our cohorts (45% and 52%).…”

Role of Adjuvant Radiotherapy in Gastric Cancer

“…As shown in Table 1 , the pattern and rate of LRR (10%–20%) after radical GC resection, including D2 resection and adjuvant treatment, are lower than those of distant metastasis, including peritoneal metastasis, in recent studies [ 26 28 29 30 31 32 33 34 ].…”

Shifting sands: the role of radiotherapy for patients with gastric and gastroesophageal adenocarcinoma

“…It is conceivable that preoperative RT for GAC may shift toward local fields directed at the primary tumor and involved nodal regions only; certainly it is worth noting that RT fields directed at the primary tumor and involved nodes only (without treatment of elective nodal region) may change interpretation of post-treatment pathological nodal status (66,67,82). Yet, while primary-tumor-directed RT may drastically reduce the RT field size and associated toxicity, the question of how RT affects patterns of failure calls this strategy into question (82,83). RT-related improvements in regional nodal control may contribute toward an overall oncologic benefit associated with RT (66,67,(82)(83)(84).…”

“…Yet, while primary-tumor-directed RT may drastically reduce the RT field size and associated toxicity, the question of how RT affects patterns of failure calls this strategy into question (82,83). RT-related improvements in regional nodal control may contribute toward an overall oncologic benefit associated with RT (66,67,(82)(83)(84). These questions and many others remain unanswered with regard to the optimal RT target volumes and treatment technique, and merit further exploration.…”