53 Initial treatment response and pattern of relapse in nasopharyngeal carcinoma (NPC) — A hazard function analysis

53 Initial treatment response and pattern of relapse in nasopharyngeal carcinoma (NPC) — A hazard function analysis

SI6 52 53 NEUTRON T H E R A P Y IN ADENOID C Y S T I C C A N C E R O F T H E SALIVARY GLANDS INITIALTREATMENTRESPONSEANDPA'Iq'ERNOF RELAPSEIN NASOP...

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SI6 52

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NEUTRON T H E R A P Y IN ADENOID C Y S T I C C A N C E R O F T H E SALIVARY GLANDS

INITIALTREATMENTRESPONSEANDPA'Iq'ERNOF RELAPSEIN NASOPHARYNGEALCARCINOMA(NPC)-- A HAZARDFUNCTION ANALYSIS

F.-J. Prott, It. P~t~r =, U. Haverkamp,O. Micke, I. Johli~ N. Willich Klini.kend puliklinik flit Struldentherepie Universityof M0aster/Gemm~. tKlinik far Straldeatherapie and Joiolo~e.Universityof V i e a n a / A ~

Simon G. Tang., W.M. Liang.. S. Tsang., J.H. Hong Department of Radiation Oncology, Chang Gung Memorial Hospital

Purpose: The slowly growing adenoid cystic carcinomas seem to have a better response to fast neutron irradiation than to photon beam therapy because of the higher r e l a y biological effectiveness. Material and Methods: In MOnster 64 patients with adenoid cystic carcinomas of the salivary glands were treated with fast neutrons between 1986 and 1994 by a d,T-14 MeV neutron generator. Median age was 54 yeats. All patiens were surgically pretreated and had either macroscopic tumor lei~ (91%) or unresectable recurrences (9%). The dose applied was 15.03 Gy with a single dose of 1.67 CO, given hypofi'actionated three times a week. Median follow up of the patients was 29 months. Results: 78% of patients achieved a complete remission after neutron therapy and 22% a partial remission The survival probability calculated by Kaplan-Meier method was 91% after I year, 76% after 2 years and 3 2 0 after 5 years. The recurrence-fi'ee survival was 9 0 0 after 1 year and 69% after 2 years. The early side effects were skin reactions I°-H° (57%) (EORTC/RTOG score) and mucositis l°-II° (32°,6). Two patients suffered from radiation induced mucosal ulcers III°-IV°. Late effects were impairment of sense of taste in 61% and xerostomia in 32%. Conclusions: Neutron beam therapy seems to be an effectiv treatment in these negatively selected patients, compared to the results photon irradiation reported from literature with an average complete remission of only 27*/..

From 1979 to 1993, 501 NPC patients' data were retrospectively reviewed to study initial treatment response and subsequent pattern of relapse after radical radiation therapy (RT). Factors contributing to clinical complete remission at primary (PCR) and regional (NCR) sites were for PCR: sex (p=0.044); T stage (p=0.000), biopsy methods (p=0.000); RT dose to nasopharynx (p=0.000); the performance of brachytherapy (p=0.000) and for NCR: N stage (p=0.000); nodal location (p=O.000); RT dose to nasopharynx (p=0.000); the performance of brachytherapy (p=0.000). Logistic regression model revealed that the most important independent factors for PCR and NCR were T stage and the performance of brachytherapy respectively. Analysis for risk of recurrence per 2-year interval was performed using a hazard function analysis. For patients with PCR and NCR (N=249), the risk of distant relapse was greatest during the first 2-year interval after treatment and decreased to 0.2% by 12 years (correlation coefficient, r=-0.79, p=0.0338). However, the risk of loco-regional recurrence increased to maximum at four year after treatment and then decreased to a fairly stable level at 6 to 12 year post-RT (r=-0.54, p=0.2093). For patients without CR al primary and/or regional sites (N=136) or patients with negative node at regional sites (N=116), no significant correlation between the risk of recurrence and time interval post-RT can be identified. We thus recommend that extended follow-up be conducted for NPC patients in order to find out any late recurrence.

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PROGNOSTIC DETERMINANTS OF NASOPHARYNGEAL CANCER TREATED BY RADIOTHERAPY ALONE: RESULTS OF A MULTIVARIATE ANALYSIS ON 378 PATIENTS.

INDIVIDUAL SURVIVAL PROBABILITY ESTIMATION IN PAPILLARY THYROID CANCER

F. B. Geara; G. Sanguineti, S. L. Tucker, A.S. Garden, L. J. Peters, and K.K. Ang. The University of Texas, M. D. Anderson Cancer Center, Houston, USA Purooso: This retrospective study was conducted to identity the prognostic factors of nasopharyngoal carcinomas (NPC) treated by radiation therapy alone. Methods and material: Between 1954 and 1992, 378 patients with NPC wore treated by definitive radiation at the University of Texas M. D. Anderson Cancer Center, following a consistent dose and volume prescription policy. The median age was 52 years (range: 16-86 years). The majority of the patients were white caucasians (282 patients,75%). Histologically, 193 tumors (51%) were squamous cell carcinomas, t 54 (41%) lymphoepitheliomas, and 31 (8%) unclassified carcinomas. Three fourths of the patients presented with AJCC stage IV disease (T4, N0-3, 118 patients; T13, N2-3 164 patients). Median follow-up time was 10 years (range 0.3 to 28.6 years). Results: The 5- and 10-year actuarial survival rates were 48% and 34% respectively, with 184 patients (49%) dying of nasopharyngeal cancer. Actuarial local and regional control rates at 5, and 10 years were 71%, 66% and 84%, 83%, respectively. Actuarial rates for distant metastasis at the same time points were 30% and 32%, respectively. Advanced T-stage, squamous histology, and presence of cranial nerve (CN) deficits were poor prognostic factors for local control in both univariate and multivariate analyses. N-stage and tumor histology were significant factors for neck control. Advanced T-stage, N-stage, and nonlymphoepithelioma histology were independent adverse prognostic factors for survival. Advanced N-stage and low neck disease were independent adverse prognostic factors for distant metastasis. The actuarial incidence of grade 3-5 late complications was 16%, 19%, and 29% at 5, 10, and 20 years respectively. Conclualons: Advanced T- and N-stage tumors, differentiated squamous histology, presence of CN deficit, and low neck disease were found to be poor prognostic indicators for NPC in this study. Patients with NPC who present with these adverse features should be considered for dose escalation or combined medality studies.

[£sik 0., Tusnddy (7. *, Daubner K., Ndmeth G., FQZy M., Szentirmay Z National Insl irate of Oncology, *MathematicalInstitute of the Hungarian Academy of Sciences, Budapest, Hangary

Purpose. The typically benign, but occasionally rapidly fatal clinical course of papillary thyroid canc=r has raised the need for individual survival probability estimation, to tailor the treatment strategy exclusivelyto the given patient. Methods and MateriaLs A retrospectivestudy was performed on 400 papillary thyroid cano~r patients, with a mean follow-uptime of 10.3 years, to establish a clinical database for tuff- and multivariate analysis of the survival probabilityrelated prognostic factors (KeplawMeier product limit method and Cox regression). In the next step the most important clinical ¢vems were investigated and survival functinus for each patient were calculated on the basis ofa Markov renewal model. The basic concept of this approach is as follows:each patient has an individual disease course, which (besides the initial cfiulcal categories) is affected by special events, e.g. internal cevariates (local/regional/distant relapses), that a patient experiences throughout the course of the disease. The individual survival curves for each patient were calculated, summation of which resulted in an overall cause-specificsurvival fimctionvalid for the entire group. Resu/ts. The patient's age, a distant metastasis at presentation, the extent of the surgical intervention, the primary tumor size, the external irradiation dosage and the degree of TSH suppression proved to be statistically significant (in that sequence) and independent prognostic factors as concerns cause-specific survival in multivariate studies During follow-up, 14%, 14%, 9% and 12% of the patients underwent local/regional/distant relapses or thyroid cancer-related death. Through use of the above six independent clinical vanablus aad the parameters relating to the interrelations of the four clinical events, mean cause-specific survival probabilities of 88%0, 83% and 78% were determined at 10, 20 and 30 years, respectively. Three groups were formed from study cases according to their 30-yeax survival probabilities: the estimated survival rates for lowrisk, high-risk and intermediate-risk groups were >92%, ~78% and 7991%, respectively. In the three groups, the ratios of tumor-related deaths were 0%, 31% and 6°/,, respectively. Conclusion. The constructed survival function permits a prediction of the individual survival probability of extrastody cases under the given treatment conditions and within the given population, and thus affords a rationale for individualization of the treatment of papillary thyroid cancer patients.