Interstitial radiotherapy combined with interstitial hyperthermia in the management of recurrent tumors

Thermoradiotherapy with combined interstitial and external hyperthermia in advanced tumours in the head and neck with depth > or = 3 cm

Advanced tumours in the head and neck 3-6 cm depth are too deep to be completely heated by external 915 MHz microwaves. A preliminary study was performed using interstitial plus external hyperthermia combined with external beam radiation therapy to heat tumours to depths > or = 3 cm. Nine advanced metastatic lesions of squamous cell carcinoma located in the head and neck were treated between 1987 and 1990 with the combined hyperthermia technique and radiation doses of 38-60 Gy (mean of 49 +/- 3 Gy). The mean tumour volume was 58 +/- 9 (SE) cm3 (range 24-94 cm3) with a mean tumour depth of 3.9 +/- 0.3 cm (range 3-5.5 cm). The deeper aspects of the tumour were heated by interstitial 915 MHz microwave antennas and the superficial aspects heated by external 915 MHz applicators. A single plane of polyurethane closed-end catheters, 16 Ga, were inserted under local anaesthesia approximately 1.5-2 cm apart in parallel arrays at the base of a lesion behind the sternomastoid muscle, or an equivalent site in a dissected neck, extending forward and angled deeply no more than 15 degrees. Hyperthermia was administered twice weekly immediately after radiation therapy in a mean of 5.3 +/- 0.7 external heat sessions (range 3-7) and a mean of 3.5 +/- 0.6 interstitial heat sessions (range of 1-6). Interstitial hyperthermia was usually administered in alternating sessions with external hyperthermia, but in some patients all of the sessions of one modality were administered followed by all of the sessions of the other modality. In no case were both interstitial and external heatings performed on the same day. Surface thermometers were used to monitor skin temperature during external hyperthermia sessions. Results showed that by 8 weeks after completion of treatment, six lesions exhibited a complete response (67%) and three a partial response (33%). One of the partial responses continued to regress and became a complete response (78% complete response). The recurrence rate in complete responders was 14% (1/7) with time to recurrence of 7.7 months. Six lesions were recurrence-free at last follow-up of 21.3 +/- 8.8 months. Skin reactions were absent in four fields (44%), erythema was noted in five (56%) and thermal blistering in one (11%). Ulceration occurred only in association with tumour breakdown when the skin was infiltrated by tumour (three patients, 33%).(ABSTRACT TRUNCATED AT 400 WORDS)

Interstitial thermoradiotherapy for recurrent head and neck cancer

From 1985 to 1987, 22 head and neck sites in 20 patients with recurrent tumors were treated with interstitial thermoradiotherapy (ITRT). The sites treated were 15 neck (68%), four tongue (18%), two parotid (9%), and one buccal mucosa (4%). Squamous cell carcinoma was diagnosed in 21 sites and adenocarcinoma in the other. All patients had prior radiotherapy (RT), including 15 who underwent a combination of RT and surgery. Interstitial RT with iridium 192 (mean dose, 40 Gy) was combined with interstitial microwave hyperthermia (mean thermal dose, 90 units). Complete response (CR) was obtained in 15 (68%) sites and partial response (PR) in seven (32%) sites. There were no local recurrences in the 15 CR patients during a period of observation of up to 30 months. Of the seven PR patients, one had radical neck dissection and is free of tumor after 28 months. Tumor volume was an important factor influencing CR (P less than .001), whereas RT and thermal dose were not (P = .3). Of the 20 patients treated, 19 experienced major subjective benefit. Serious complications occurred in two patients: one had localized soft tissue necrosis, the other had aspiration pneumonia. ITRT was well-tolerated by patients despite prior aggressive therapy. High objective response rate and low toxicity demonstrate the value of this treatment combination in the management of patients with postradiation recurrence of head and neck tumors.