Radiation therapy of squamous carcinoma of the tonsil: an analysis of prognostic factors and of treatment failures

Abstract

A retrospective analysis of the results of treatment by primary irradiation of 87 cases of squamous-cell carcinoma of the tonsil at one institution over a 20-year period is presented. Survival at 5 years for all patients was 20%. The major determinants of survival were tumour size (T) and nodal status (N) at presentation. Degree of histological differentiation had no prognostic significance. Initial failure occurred in the primary tonsil site or in cervical lymph nodes in almost all cases. It is clear that treatments that increase loco-regional control are needed if the prognosis for the more advanced tumours is to be improved and it is suggested that a combined-modality approach (surgery plus irradiation) needs to be explored. For early lesions, primary radiation therapy remains the treatment of choice.

Modified Tumor Classification With Inclusion of Tumor Characteristics Improves Discrimination and Prediction Accuracy in Oral and Hypopharyngeal Cancer Patients Who Underwent Surgery

“…A 20-year retrospective analysis of 87 cases of tonsillar SCC found that the major determinants of survival were tumor size and nodal status at presentation. 25 The degree of tumor differentiation had no prognostic significance. In contrast, a more recent study reported by Larsen et al 9 found tumor differentiation to be a strong prognostic factor for nodal metastasis, independent of other histological features.…”

Additional parameters to improve the prognostic value of the 8th edition of the UICC classification for human papillomavirus‐related oropharyngeal tumors

“…In the literature, the predictive value of the 7th edition of the TNM classification for oropharyngeal carcinomas, and for N classification in particular, has shifted over time as a consequence of the epidemic of HPV‐associated HNSCCs 13–34 . This shift prompted the publication of a new edition of the UICC staging system.…”

“…During multidisciplinary counseling, treatment plans were based on tumor size, neck staging, presence of distant metastases, tumor histology and cytology of metastases, feasibility of surgery, clinical condition, comorbidities, and histopathology of resection specimens in case of surgery. Elective treatment of the neck was performed routinely—also in the N0 neck—because of the high incidence of occult metastases in TSCC 15,19–21 …”

“…We found 10 studies published prior to 1990 all reporting N classification to be of prognostic importance (although only 2 studies provided results based on statistical analysis), while only 4 out of 12 studies published from 1990 onwards showed N classification to be of prognostic relevance (see Table 1). 13–34 In a previous study we tested the prognostic value of N classification in a group of 81 HPV‐positive and HPV‐negative TSCCs and found a decrease in prognostic value of N classification in the whole group 35 . N classification was of prognostic relevance only when tonsillar tumors were not HPV‐associated.…”

“…Elective treatment of the neck was performed routinely-also in the N0 neck-because of the high incidence of occult metastases in TSCC. 15,[19][20][21] The investigation was conducted in accordance with the declaration of the 18th meeting of the world medical association in Helsinki 1964 and subsequent revisions. Approval for the study protocol was granted by the institutional ethical committee.…”