Since multiple studies have demonstrated that PET can identify responders and non-responders to induction chemotherapy, using FDG-PET imaging to guide treatment decisions has prompted interest in clinical practice. The aim of this study was to evaluate whether changing chemotherapy regimen during radiation based on PET response to induction chemotherapy can improve clinical complete response (cCR) in patients with unresectable esophageal squamous cell carcinoma (ESCC).

A total of 216 patients with baseline PET scan were randomized to one of 2 induction chemotherapy arms: paclitaxel/cisplatin (TP) on days 1, 22 or FOLFOX (oxaliplatin, leucovorin, 5-FU) on days 1, 15, 29. Repeat PET was performed on days 36-42 and changes in max standardized uptake value (SUVmax) from baseline were assessed. Using a predefined cut-off value of a 35% decrease in SUVmax, PET responders (≥35% decrease in SUVmax) continued on the same chemotherapy regimen during radiotherapy, whereas PET non-responders (<35% decrease in SUVmax) crossed over to an alternative chemotherapy regimen concomitantly with radiation. All patients received external-beam radiation using intensity-modulated radiotherapy. The prescribed dose is generally 50-60 Gy in 25-28 fractions, 5 days per week.

Inclusion Criteria:

1. Histologically confirmed squamous cell carcinoma of the esophagus;
2. Absence of hematogenous metastasis disease, confirmed by endoscopic ultrasound (EUS) and PET-CT scan (according to UICC TNM version 8);
3. Not suitable for surgery (either for medical reasons or patient's choice);
4. Age at diagnosis 18 to 70 years;
5. Eastern Cooperative Oncology Group performance status ≤ 2
6. No prior cancer therapy;
7. No history of concomitant or previous malignancy;
8. Hematologic function: WBC ≥ 4.0×109/L, PLT ≥ 80×109/L, Hb ≥ 10mg/dL;
9. Renal function: Cr ≤ 1.25×UNL;
10. Hepatic function: BIL ≤ 1.5×UNL, ALT/AST ≤ 2.5×UNL;
11. Documented informed consent to participate in the trial.

Exclusion Criteria:

1. Younger than 18 or older than 70 years of age;
2. ECOG performance status of 3 or above;
3. Other cancer history;
4. Previous radiotherapy history;
5. Subjects with distant metastases;
6. Pregnancy or breast feeding. Women of childbearing age must use effective contraception;
7. Serious cardiovascular disease (congestive heart failure, uncontrollable arrhythmia, unstable angina, myocardial infarction, serious heart valve disease, resistant hypertension);
8. Evidence of bleeding diathesis or serious infection.