Second primary malignancies following the treatment of early stage ovarian cancer: update of a study by the National Cancer Institute of Canada--Clinical Trials Group (NCIC-CTG).

BACKGROUND

Ovarian cancer is the leading cause of death from gynecological malignancies and the fourth most frequent fatal malignancy in women. Despite improved surgical techniques as many as 20% of women with early stage disease will eventually relapse and die from their disease. The post-operative management of these women remains controversial. Here we present the long term follow-up data of our previously published study, as well as the incidence of second primary malignancies in these women.

PATIENTS AND METHODS

Two hundred fifty-seven eligible patients with stage I, IIA 'high risk' ovarian carcinoma and IIB, IIIO (disease confined to pelvis) were randomized to either whole abdominal radiotherapy 2.250 rads in ten fractions (107 patients), melphalan 8 mg/m2/d x 4 weeks x 18 courses (106 patients) or intraperitoneal chromic phosphate 10-20 mCi (44 patients). All patients were initially treated with pelvic radiotherapy.

RESULTS

Overall survival estimates at 10 years were: 45% in the whole abdominal radiotherapy arm; 49% in the melphalan arm and 50% in the intraperitoneal chromic phosphate arm (P = 0.30). Relapse-free survival estimates at 10 years were: 50% in the whole abdominal radiotherapy arm, 62% in the melphalan arm and 51% in the chromic phosphate arm (P = 0.147). Long term follow-up has not demonstrated a significant difference between treatment arms. Second primary malignancies developed in 29 women (11%) after 2,229 person years of follow-up. This compares to 18.7 second primary malignancies which would have been expected in this group of age-matched controls and was statistically significant (P = 0.018). There was no significant difference in the total number of second primary malignancies between treatment arms. Melphalan appeared to be associated with an increased risk of developing leukemia/myelodysplastic syndrome compared to the whole abdominal radiotherapy arm (P = 0.06).

CONCLUSIONS

Long-term follow-up has not demonstrated a significant difference in overall or disease free survival between treatment arms. An excess of second primary malignancies (35%) was observed suggesting that lifelong surveillance is required in this population. Further research with newer treatment programs are needed to improve the cure rates in this population.