The significance of the parametrium in the operative treatment of cervical cancer.

The first sharp improvement in the operative treatment of cervical cancer was the shifting of the plane of resection away from the tumour into the parametria. This permitted resection of the primary cancer with a margin of healthy tissue. Systematic studies of excised parametrial tissue, carried out around the turn of the century, showed four types of parametrial involvement: continuous, discontinuous, carcinomatosis of the parametrial lymphatics, and parametrial lymph node involvement. It is well known that histologically demonstrated parametrial involvement often contradicts the clinical stage. So-called staging laparotomies are meant to address this problem but they, too, are inadequate since most parametrial cancer deposits are microscopic and cannot be palpated. In our own studies of totally extirpated parametria, contiguous cancer spread into the parametria never exceeded 10 mm, not even in the largest still-operable tumours. Thus the theory of contiguous, direct cancer spread to the pelvic wall is wrong. Parametrial involvement usually occurred as cancer deposits in the rarely mentioned parametrial lymph nodes. Parametrial involvement correlates better with the size of the primary tumour, expressed as the tumour-cervix quotient, than with the clinical stage. The smallest tumours, without showing continuous parametrial involvement, had a 3.4% incidence of positive nodes. Thirty-five per cent of the patients with the largest tumours had positive parametrial nodes. Parametrial lymph nodes were found in 280 (78%) of 359 surgical specimens processed as giant sections. Sixty-three patients (22.5%) had positive parametrial nodes. The nodes at the pelvic wall were involved in 80% of the patients with positive parametrial nodes. The five-year survival rate was 84% if the parametria were free of disease, but it dropped to 53% with any type of parametrial involvement. Survival rates did not differ much if only the parametrial nodes or only the pelvic nodes were positive (56% and 66%, respectively). However, if both groups were positive survival dropped to 43.1%. Positive parametrial nodes can be located anywhere in the parametrium; therefore, surgery must remove the entire structure. It remains to be seen whether an exception can be made for small Stage Ib tumours, or if lymphadenectomy can be omitted in these patients. If so, radical vaginal surgery may be the treatment of choice.