Survival rates in patients with differentiated thyroid carcinoma. Influence of postoperative external radiotherapy

Abstract

Nine hundred thirty-two patients with papillary and follicular thyroid carcinomas were seen at the Departments of Medicine, Surgery, and Radiology of the University of Essen, Essen, Germany, between 1970 and 1986. In addition to standard treatment by surgery, radioactive iodine and medical thyroid stimulating hormone (TSH) suppression, 346 patients had received conventional external irradiation to the neck (mostly 40-60 Gy) before referral to our institutions, whereas 586 patients had not received radiotherapy. From the follow-up data of these patients, survival rates were calculated separately for tumor Stages T1 (n = 203), T2 (n = 552), and T3/T4 (n = 277) using life-table analysis. Distribution of risk factors (histologic type of tumor, grading of malignancy, presence of distant metastases, age and sex) was similar in all groups with the one exception, that the radiotherapy patients with Stage T3/T4 were older. There was no significant difference in the life expectancy of irradiated and not irradiated patients by Breslow and Mantel-Cox tests. In Stages T1, T2, and T3/T4, 75% of the radiotherapy patients survived for 10.6 +/- 0.32, 11.5 +/- 0.61, and 6.71 +/- 0.85 years, respectively; the figures for the nonirradiated patients were 9.4 +/- 0.17, 10.8 +/- 0.37, and 6.26 +/- 0.51 years, respectively. When survival rates were calculated separately for patients with Stage T3/T4 older and younger than 40 years, there was no obvious effect of radiotherapy in the younger group, whereas in the older patients, improvement of survival by radiation just failed to reach statistical significance (P less than 0.09). In conclusion, this retrospective analysis failed to prove that survival is prolonged in patients with differentiated carcinoma by administration of conventional external radiotherapy after surgery. A benefit to older patients with locally advanced tumors has still to be demonstrated.

Prognostic Variables of Papillary Thyroid Carcinomas with Local Invasion.

“…During this limited follow-up study, the 5-and 10-year survival rates were comparable with those in previous studies [24]. The role of adjuvant external radiotherapy for the post-operative treatment of well differentiated human thyroid cancer is still a controversial issue [25,26], although its use has been reported in patients with well-differentiated thyroid cancer with post-operative residual disease, local recurrence, or in 1311 treatment refractory patients [27,28]. In a recent study with a limited followup, Lin et al [29] found that external radiotherapy did not improve the survival of patients with welldifferentiated thyroid cancer at an advanced clinical stage.…”

Outcome after treatment for papillary thyroid cancer

“…The role of adjuvant external radiotherapy for the postoperative treatment of well-differentiated human thyroid cancer is still a controversial issue, 21 although its use has been reported in patients with postoperative residual disease, local recurrence, or in patients refractory to 131 I treatment. 22,23 In our recent studies with a limited period of follow-up, we found that external radiotherapy did not improve the survival of patients with well-differentiated thyroid cancer at an advanced clinical stage.…”

The role of external beam radiotherapy in the treatment of papillary thyroid cancer

“…For example, one center reports the importance of prophylactic EBRT in differentiated thyroid cancer even among patients with no microscopic residual disease based on improvement in the locoregional relapse-free and cause-specific survival in patients who underwent adjuvant EBRT after complete surgical resection (Esik et al 1994). In contrast, investigators from other centers do not routinely recommend EBRT for PTC as no improvement in overall survival was observed (Benker et al 1990, Lin et al 1997. In fact, there was a higher survival rate among those who did not receive EBRT in one study (Lin et al 1997).…”

“…For example, it is generally accepted that no postoperative EBRT is necessary for a young patient with limited gross residual disease where there is good demonstration of RAI uptake (O'Connell et al 1994, Tsang et al 1998, Brierley et al 2005. Others, however, failed to find any correlation of outcome with age (Benker et al 1990). Due to these opposing views from different groups, confusion arises for both the patient as well as the physician, as EBRT might be strongly recommended in one center but not recommended at all at another center.…”