Anatomic and geometric precision in radiotherapy.
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Biomedical subjects
Publications and source records attributed to J E Marks.
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The incidence of palpable and occult cancer and the absence of cancer in lymph nodes were determined for individual sites in the larynx and pharynx of 540 patients who underwent neck dissection. The incidence of palpable cancer in lymph nodes was lowest for cancers of the central supraglottis and transglottis (32-41%), intermediate for cancers of the marginal supraglottis and glossoepiglottis (48-57%), and highest for cancers of the pyriform sinus (69%). The incidence of occult cancer in lymph nodes for individual sites in the larynx and pharynx was determined by pathologic study of neck dissection specimens from 253 patients without palpable lymph nodes (NO neck). The incidence of occult lymphatic metastases in the NO neck and the need for elective neck irradiation were least for cancers of the transglottis and central supraglottis (14-16%), intermediate for cancers of the glossoepiglottis and the marginal supraglottis (20-38%), and greatest for cancers of the pyriform sinus (47%). The risk of nodal recurrence increased from 8% for those without cancer in lymph nodes to 38% for those with occult or palpable cancer in lymph nodes. A policy of observing the NO neck in patients with a low incidence of occult lymphatic metastases and a low risk of neck recurrence to avoid the unnecessary irradiation of many to benefit a few is discussed.
We determined the success of elective neck irradiation for 104 patients with carcinomas of the larynx and pyriform sinus whose only surgery was resection of the primary cancer. Tumor regrew in the neck of 22 patients (21%) and was twice as likely to recur in the neck when there was simultaneous regrowth of tumor in the laryngeal remnant or pharynx. The observed rate of neck recurrence did not vary appreciably from the expected rate as determined by the incidence of occult lymphatic metastases in dissected neck specimens. The rate of neck recurrence was less after high doses (greater than 45 Gy) than low doses (less than or equal to 45 Gy) of irradiation, suggesting a benefit from higher doses of elective neck irradiation.
PURPOSE: This study was undertaken to determine the risk of cervical metastases to the contralateral side in patients treated for carcinoma of the larynx and pharynx. PATIENTS AND METHOD: Retrospective evaluation of 846 patients treated between 1962 and 1981 with carcinoma of the supraglottis, transglottis, and pyriform sinus were reviewed. Lesions were classified as either transglottic with fixed vocal cord (TG-F), transglottic with mobile vocal cords (TG-M), central supraglottic (SG-C), marginal supraglottic (SG-M), glossoepiglottic cancers of the suprahyoid epiglottic, vallecula, and tongue base (SG-GE), and cancers of the pyriform sinus (PS). RESULTS: Contralateral lymph node metastases were identified at presentation or later developed in SG-GE 26%, SG-M 14%, PS 13%, SG-C 7%, TG 4%. Contralateral metastases were significantly higher in patients with ipsilateral metastasis. The risk of contralateral metastasis was unrelated to the primary tumor size. CONCLUSIONS: All but 79 patients received variable doses of irradiation to the contralateral neck. Therefore, the risk of metastatic disease is probably higher than reported. Parotid-sparing radiation technique is suggested for centrally located cancers of the supraglottis and transglottis when ipsilateral nodes are not involved because the risk of contralateral neck involvement is sufficiently low that opposite neck irradiation may be safely avoided.
INTRODUCTION: Keratinization may be a vulnerable aid in predicting response to therapy for nasopharyngeal carcinoma. METHODS: The presence or absence of keratin in biopsy specimens was correlated with tumor behavior, locoregional control, patterns of failure, and survival of patients irradiated for nasopharyngeal carcinoma. RESULTS: Patients with keratinizing squamous-cell cancers (World Health Organization [WHO] type 1) had a higher incidence (76%) of locally advanced tumors than those with nonkeratinizing (WHO type 2) and undifferentiated (WHO type 3) cancers (55%). The former group of patients had a lower incidence (29%) of lymph node metastases than the later group (70%). Primary tumor was controlled in 62% and neck nodes were controlled in 82% of all patients. Primary tumor control rates were 29% in patients with keratinizing squamous-cell cancers and 79% in those with nonkeratinizing and undifferentiated cancers (P = .001). Nodal control rates were 76% for keratinizing squamous-cell cancer and 85% for nonkeratinizing and undifferentiated cancers (P = .001). The incidence of distant metastases was 6% in patients with keratinizing squamous-cell cancer and 33% in those with nonkeratinizing and undifferentiated cancers (P = .001). Patients with keratinizing squamous-cell cancers, even though they had a lower incidence of lymphatic and distant metastases, had a poorer survival rate because of a higher incidence of deaths from uncontrolled primary tumors and nodal metastases. The 5-year survival rates were 35% for all patients, 6% for those with keratinizing squamous-cell cancers, and 51% for nonkeratinizing and undifferentiated cancers respectively (P = .001). CONCLUSION: Higher doses of external beam radiotherapy with or without brachytherapy boost may be needed to improve local control and survival of patients with keratinizing squamous-cell carcinoma of the nasopharynx, whereas an effective systemic therapy is needed for nonkeratinizing and undifferentiated cancers, which tend to metastasize.
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