Type of second primary malignancy after achieving complete response by definitive chemoradiation therapy in patients with esophageal squamous cell carcinoma.

BACKGROUND

While the standard treatment for stage II-III (non-T4) esophageal squamous cell carcinoma (ESCC) is neoadjuvant therapy followed by esophagectomy, definitive chemoradiation therapy (dCRT) is an option to treat ESCC patients who reject or may not tolerate surgical treatment. Second primary malignancy (SPM) is a problem for long-term survivors after achieving complete response (CR) by dCRT.

METHODS

The source of the subjects in this study was the patients with stage II/III (excluding T4 disease) ESCC (UICC6th) who underwent dCRT from 2000 to 2011 at the National Cancer Center Hospital, Japan. SPM, defined as malignancy newly detected at different site from the initial disease, was checked in patients who achieved CR by the initial dCRT.

RESULTS

Among the 285 patients with stage II/III (excluding T4 disease) ESCC who underwent dCRT, 185 patients achieved CR. SPM was detected in 49 patients (median time to developing SPM, 41.5 months), accounting for 19.3% (95% CI 0.137-0.257) as the 5-year cumulative risk of SPM. SPMs were head and neck cancer (n = 12), gastric cancer (n = 12), esophageal cancer (n = 7), lung cancer (n = 5), colon cancer (n = 4), diffuse large B-cell lymphoma (n = 3), bladder cancer (n = 2), small intestinal cancer (n = 1), cholangiocarcinoma (n = 1), malignant melanoma (n = 1), and breast cancer (n = 1). There were no significant differences in baseline characteristics between the patients who developed SPM (n = 49) and others (n = 136).

CONCLUSIONS

Because second primary malignancy developed often after achieving CR by dCRT for ESCC, it should be followed carefully.