Typical radiation technique as described in the current RTOG esophagus trial (E-0113)

RADIATION THERAPY ONCOLOGY GROUP. RTOG E-0013 NON-OPERATIVE THERAPY OF LOCAL-REGIONAL CARCINOMA OF THE ESOPHAGUS: A RANDOMIZED PHASE II STUDY OF TWO PACLITAXEL-BASED CHEMORADIOTHERAPY REGIMENS

Arm 1 (5-FU-based)
Induction chemotherapy with 5-FU, cisplatin, paclitaxel (up to 2 cycles) followed by (on day 29 of the last cycle)continuous
96-hr. infusion 5-FU and weekly paclitaxel with concurrent radiotherapy* (50.4 Gy) [G-CSF given from days 6-15 and 34-42]

Arm 2 (Non-5-FU-based)
Induction chemotherapy with paclitaxel and cisplatin
(up to 2 cycles) followed by (on day 29 of the last cycle) continous
96-hr. infusion paclitaxel and weekly cisplatin with concurrent radiotherapy* (50.4 Gy). Routine G-CSF administration is not planned.

6.0 RADIATION THERAPY

Participating institutions must utilize 3-D CT planning and must be able to comply with the criteria described below.

6.1 Dose Specifications

6.1.1 The prescription dose will be specified at the ICRU-50 reference point, which is defined in Section 6.4.1.3. Note: this point will usually be the isocenter (intersection of the beams). The isodose curve representing 93% of the prescription dose must encompass the entire planning target volume (PTV), which is defined in Section 6.4.1.2.

6.1.2 The daily prescription dose will be 1.94 Gy at the ICRU reference point. 1.8 Gy (which corresponds to the 93% isodose curve) is to be delivered to the periphery of the PTV.

6.1.4 The total dose for both arms will be 50.4 Gy (1.8 G/Fx/day) prescribed to the periphery (93% isodose curve) of the PTV.

6.3.1 A volumetric treatment planning CT study will be required to define gross tumor volumes (GTV) and planning target volume (PTV). For this study, the local regional nodes (whether clinically positive or negative) will be included in the clinical target volume (CTV) (Appendix VI) . Each patient will be positioned in an individualized immobilization device in the treatment position on a flat table. Contiguous CT slices, 3-5 mm thickness of the regions, harboring gross tumor and grossly enlarged nodes and 8-10 mm thickness of the remaining regions, are to be obtained starting from the level of the cricoid cartilage and extending inferiorly through the liver. The GTV and PTV and normal organs will be outlined on all appropriate CT slices and displayed using beam’s eye view. Normal tissues to be contoured include both lungs, skin, heart, spinal cord, esophagus, and liver. A measurement scale for the CT image shall be included.

6.3.2 For cervical primaries (defined as tumors above the carina), the bilateral supraclavicular nodes need to be included. The preferable method is a 3 field technique (2 anterior obliques and a posterior field). In most cases, this is not possible; therefore, it is acceptable to initially treat AP/PA to approximately 39.6 Gy then switch to obliques to exclude the spinal cord. The supraclavicular field, which is excluded from the obliques, can be supplemented with electrons to bring the total dose up to 50.4 Gy (calculated 3 cm below the skin surface). For mid-esophageal primaries (at or below the carina), the paresophageal nodes need to be included—not the supraclavicular or celiac. For distal/gastroesophageal primaries, the field should include the celiac nodes.

6.3.3 Barium swallow during the planning CT is optional provided a diagnostic chest CT was done with contrast to delineate the outline of the esophagus.

6.3.4 Optimal immobilization is critical for this protocol. Alpha cradle or approved alternative immobilization system is required; Patients may be placed on the supine or prone position. In general, supine is recommended for proximal and distal primaries whereas prone is recommended for mid-esophageal

6.4.1.1 Gross Tumor Volume (GTV) is defined as all known gross disease as defined by the planning CT and clinical information. Gross tumor includes the primary tumor (GTV-P) only. Note: ICRU Report #50 also defines a clinical target volume (CTV) that includes the area of subclinical involvement around the GTV. For this protocol, we have chosen to define the CTV a minimum of 4 cm proximal and distal and 1 cm lateral beyond the GTV delineated by CT scan and/or endoscopy (endoscopy is preferable). The final CTV may be larger since for cervical primaries, the supraclavicular nodes need to be included, and for distal primaries, the celiac nodes need to be included in the treatment fields.

6.4.1.2 Planning Target Volume (PTV) will provide margin around the CTV to compensate for variability in treatment setup, breathing, or motion during treatment. A margin around the CTV will define the PTV. The PTV volume must include a minimum of 1 cm and a maximum of 2 cm around the CTV. Therefore, the superior and inferior margins will be approximately 5 cm beyond the GTV, and the lateral margins will be approximately 2 cm beyond the GTV. Once again, the final PTV may be larger since for cervical primaries, the supraclavicular nodes need to be included, and for distal primaries, the celiac nodes need to be included in the treatment fields.

6.8.2 The gross tumor volume (GTV) includes the known disease as determined by physical examination, imaging studies and other diagnostic information.

6.8.3 The clinical target volume (CTV) includes the area of subclinical involvement around the GTV. The CTV is the GTV plus the margin for clinical negative or positive local regional nodes.

6.8.4 The planning clinic volume (PTV) is the CTV plus a margin to ensure that the prescribed dose is actually delivered to the GTV. This margin accounts for variations in treatment delivery, including variations in set-up between treatments, patient motion during treatment, movement of the tissues that contain the GTV (e.g., respiration), and size variations in the tissue containing the GTV. The PTV is a geometric concept.