Precise delineation of clinical target volume for crossing-segments thoracic esophageal squamous cell carcinoma based on the pattern of lymph node metastases.

BACKGROUND

This work aims to investigate lymph node metastases (LNM) pattern of crossing-segments thoracic esophageal squamous cell carcinoma (ESCC) and its significance in clinical target volume (CTV) delineation.

METHODS

From January 2000 to December 2014, 3,587 patients with thoracic ESCC underwent surgery including esophagectomy and lymphadenectomy at Shandong Cancer Hospital and Institute. Information of tumor location based on preoperative endoscopic ultrasonography (EUS) and postoperative pathological results were retrospectively collected. The extent of the irradiation field was determined based on LNM pattern.

RESULTS

Among the patients reviewed, 1,501 (41.8%) were crossing-segments thoracic ESCC patients. The rate of LNM were 12.1%, 15.2%, 8.0%, 3.0%, and 7.1% in neck, upper mediastinum, middle mediastinum, lower mediastinum, and abdominal cavity for patients with upper-middle thoracic ESCC, 10.3%, 8.2%, 11.0%, 4.8%, 8.2% for middle-upper thoracic ESCC, 4.8%, 4.8%, 24.1%, 6.3%, 22.8% for middle-lower thoracic ESCC and 3.9%, 3.1%, 22.8%, 11.9%, 25.8% for lower-middle thoracic ESCC, respectively. The top three sites of LNM were 105 (12.1%), 108 (6.1%), 101 (6.1%) for upper-middle thoracic ESCC, 108 (8.2%), 105 (7.5%), 106 (6.8%) for middle-upper thoracic ESCC, 1 (18.8%), 108 (17.9%), 107 (9.6%) for middle-lower thoracic ESCC, 1 (21.3%), 108 (16.1%), 107 (10.1%) for lower-middle thoracic ESCC.

CONCLUSIONS

Crossing-segments thoracic ESCC was remarkably common among patients. When delineating their CTV, tumor location should be taken into consideration seriously. For upper-middle and middle-upper thoracic ESCC, abdominal cavity may be free from irradiation. For middle-lower and lower-middle thoracic ESCC, besides irradiation of relative mediastinal, irradiation of abdominal cavity can't be neglected.