Brachytherapy for head and neck cancer

Current treatment options in squamous cell carcinoma of the oral cavity

Oral cavity SCC remains a significant health problem and requires a multidisciplinary approach. Treatment with surgery alone or in combination with adjuvant radiotherapy for more advanced lesions is the standard of care. Major advances have been made in surgical approaches,reconstructive options, and the rehabilitation of patients who have oral cavity SCC. These advances have significantly improved disease-specific outcome and quality of life. The future may lie in the development of treatment regimes that combine early detection with organ preservation and result in improved cure rates and quality of life.

Interstitial brachytherapy with or without external beam irradiation in head and neck cancer: Institute Rotary Cancer Hospital experience

Iridium-192 interstitial brachytherapy is practiced infrequently in developing countries, even where head and neck cancer is a major neoplasm and the technique could provide good results. This report from India is presented as an audit to validate the benefit of brachytherapy. One hundred and six head and neck cancer patients were treated by interstitial brachytherapy alone (n = 29) or combined with external irradiation (n = 77). The oral cavity and the oropharynx together constituted 82% of the sites of implanted tumours; 75% were T(1-2)N0 status. Brachytherapy was carried out using afterloaded plastic catheters and the Paris dose prescription system was followed. External cobalt-60 beam portals covered the primary and the neck. The median duration of follow-up was 22 months. The median dose of brachytherapy used alone was 60 Gy. With combined treatment, the median external radiotherapy and brachytherapy doses were 50 Gy and 25 Gy respectively. The median brachytherapy dose rate was 0.5 Gy/h. Primary and nodal recurrences were recorded in 41/106 (38.7%) and 18/106 (17.0%) patients at median intervals of 15 and 13 months respectively. Implant site failure was more common after combined treatment than with brachytherapy alone (42.8% versus 27.5%), but it did not reach statistical significance in this analysis (P = 0.15). Kaplan-Meier actuarial 5-year estimates showed 52% and 87% disease-free and overall survivals. Iridium-192 interstitial implants in suitably selected head and neck cancer patients can improve the radiotherapeutic results, with the promise of organ conservation in 50%. In India, the practice should be established in more radiotherapy centres and could be utilized in 10,000-25,000 head and neck cancer patients annually.

Long-term regional control after radiation therapy and neck dissection for base of tongue carcinoma

PURPOSE

Minimal literature exists with 10-year data on neck control in advanced head and neck cancer. The purpose of this study is to determine long-term regional control for base of tongue carcinoma patients treated with primary radiation therapy plus neck dissection.

METHODS AND MATERIALS

Between 1981-1996, primary radiation therapy was used to treat 68 patients with squamous cell carcinoma of the base of tongue. Neck dissection was added for those who presented with palpable lymph node metastases. The T-stage distribution was T1, 17; T2, 32; T3, 17; and T4, 2. The N-stage distribution was N0, 10; N1, 24; N2a, 6; N2b, 11, N2c, 8; N3, 7; and Nx, 2. Ages ranged from 35 to 77 (median 55 years) among the 59 males and nine females. Therapy generally consisted of initial external beam irradiation to the primary site (54 Gy) and neck (50 Gy). Clinically positive necks were boosted to 60 Gy with external beam irradiation. Three weeks later, the base of tongue was boosted with an Ir-192 interstitial implant (20-30 Gy). A neck dissection was done at the same anesthesia for those who presented with clinically positive necks, even if a complete clinical neck response was achieved with external beam irradiation. Neoadjuvant cisplatin-based chemotherapy was administered to nine patients who would have required a total laryngectomy if their primary tumors had been surgically managed. The median follow-up was 36 months with a range from 1 to 151 months. Eleven patients were followed for over 8 years. No patients were lost to follow-up.

RESULTS

Actuarial 5- and 10-year neck control was 96% overall, 86% after radiation alone, and 100% after radiation plus neck dissection. Pathologically negative neck specimens were observed in 70% of necks dissected after external beam irradiation. The remaining 30% of dissected necks were pathologically positive. These specimens contained multiple positive nodes in 83% despite a 56% overall complete clinical neck response rate to irradiation. Regional failure occurred in only two patients, neither of whom underwent adjuvant neck dissection. Symptomatic neck fibrosis (RTOG grade 3) was not observed. Actuarial 5- and 10-year local control was 88% and 88%, disease-free survival was 80% and 67%, and overall survival was 86% and 52%.

CONCLUSION

For base of tongue cancer, most patients can obtain long-term regional control with no severe complications after definitive radiation therapy, plus neck dissection for those who present with lymphadenopathy. Complete clinical regression of palpable neck metastases after irradiation poorly correlates with pathologic outcome. Our current policy is to include neck dissection at the time of implantation for patients who present with palpable neck metastases. We realize that this therapeutic approach may overtreat some patients, but we are reluctant to change our policy in light of these excellent outcomes.

Iridium-192 interstitial brachytherapy in carcinoma of the tongue. The importance of various tumor and physical parameters

A detailed analysis of host-tumor factors and interstitial physical factors influencing the disease-free control in carcinoma of the tongue was carried out. Twenty-eight cases of carcinoma of the tongue T1-3, NO-1, MO were treated radically with combined external irradiation and 192Iridium interstitial brachytherapy (one patient received brachytherapy only). The teletherapy dose ranged from 44 Gy to 56 Gy (average 48 Gy), the brachytherapy dose ranged from 16 Gy to 55 Gy (average 22 Gy). The interstitial practice involved loop technique in all the cases. Dose distribution analysis to assess factors influencing local control included indices of dose rate, source activity, inter-planar distance, and discontinuity in the prescribed isodose in other planes when compared to mid-plane. Two-year actuarial disease-free survival (DFS) was 46% with primary treatment and 63% when salvage treatment was also included. DFS was significantly poorer when the interplanar distance at mid-plane exceeded 10 mm (p < 0.05). Similarly, tumor control was poorer (p < 0.008) when there was discontinuity in the prescribed isodose in 1 or 2 planes (1 cm superior and inferior to mid-plane). Interplanar distance of around 10 mm, prescribed isodose continuity in all three planes and limiting the dose maximum within a factor of 2 will optimize the results of interstitial implants.