A study was made of 187 patients with parotid
pleomorphic adenoma treated by
radiotherapy. This followed surgery but with incomplete removal or
tumor spillage. In the early years of the study
radiotherapy was given by
radium needle implant done usually at the time of surgery, but from the late 1960s beam-directed external
radiotherapy with a head shell was used most commonly. A 3-field technique or wedge pair was the standard technique. The median age was 46 with nearly half the patients (87/187) aged between 40 and 60, and the ratio of women to men was 1.4:1 (110:77). Median follow-up for all patients was 14 years. One hundred fifteen patients had
radiotherapy immediately after their first operation with a recurrence rate of 0.9% (1/115). Of the 115 there were 2 cases of radionecrosis (1 major, 1 minor), 1 case of permanent facial nerve
palsy, 1
Frey Syndrome (post-
gustatory sweating), and 1 salivary
fistula. Seventy-two patients had
radiotherapy delayed until one or more recurrences had been surgically treated. Nine (12.5%) of these developed yet further recurrence after
radiotherapy. There were 2 cases of radionecrosis (1 major), 4 cases of facial nerve
palsy (3 of which were complete), 16 cases (22.2%) of
Frey Syndrome, and 1 case of malignant change in a parotid
tumor. In addition one
squamous cell carcinoma developed at the site of a needle implant 25 years later. Recurrences after
radiotherapy continued beyond 20 years of follow-up. Patients having unsatisfactory surgery due to spill at operation or
residual tumor left behind should have
radiotherapy immediately and not delayed until local recurrence occurs because of the increased morbidity and the higher incidence of yet further recurrence.