Second malignant neoplasms following treatment for primary cancer

BACKGROUND

Long term survival following treatment for primary cancer has increased significantly in the past decade. With cure comes 'survivorship'. One of the factors clearly affecting quality and length of survival is morbidity associated with treatment and the development of subsequent malignancies.

OBJECTIVE

This article aims to look at the risks associated with the development of second malignant neoplasms, give some meaningful figures, and provide suggestions for follow up.

DISCUSSION

The balance of heightened awareness and healthy lifestyle versus relentless surveillance and ongoing patient concern is a difficult one. We hope to make our patients aware of the small but significant risk of a second malignancy, advise on any appropriate screening investigations and encourage a life long relationship with their chosen family physician to enable detection of any future malignancy.

Thyroid neoplasia following irradiation in adolescent and young adult survivors of childhood cancer

OBJECTIVES

To describe a cohort of survivors of childhood malignancy at risk of developing thyroid abnormality, and propose guidelines for management of such patients.

DESIGN

Retrospective case series.

SETTING

Late-effects oncology clinic at a large children's hospital in Sydney.

SUBJECTS

142 patients who had received irradiation to the thyroid from the 1970s onwards, who attended the late-effects clinic from May 1989 to December 1998.

INTERVENTIONS

Thyroid palpation by an endocrinologist or surgeon, serum thyroid-stimulating hormone assay and thyroid ultrasound examination were performed on all subjects and, depending on findings, some subjects proceeded to fine-needle biopsy or surgery (total thyroidectomy). A few patients required adjuvant (131)I administration.

OUTCOME MEASURES

Radiation dose received; results of thyroid palpation; thyroid function tests; ultrasound findings; diagnosis of the abnormalities; and outcomes of surgical interventions.

RESULTS

49 subjects (24 of 65 patients who received scatter irradiation to the thyroid and 25 of 78 patients who received direct irradiation) had thyroid surgery. Of these, 12 in the scatter and six in the direct irradiation group were found to have thyroid malignancy. Fifty subjects with abnormal ultrasound results remain under surveillance. Having a palpable thyroid was predictive of malignancy, but age at original diagnosis, sex, current age, time since irradiation, radiation dose, nodule type and nodal involvement were not.

CONCLUSION

There is a significant risk of cancer in thyroid glands exposed to radiation as part of therapy for childhood cancer. This risk is greater for patients who received scatter (versus direct) irradiation. Nodular change is usually not apparent for many years, so lifelong surveillance is necessary. Palpation alone is not sufficient to detect thyroid cancer and thyroid ultrasound examination is recommended.