International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 1989
Dose fractionation and regeneration in radiotherapy for cancer of the oral cavity and oropharynx: tumor dose-response and repopulation.
In a retrospective study, local control of the primary tumor in 498 squamous cell carcinomas of the oral cavity and oropharynx was analyzed with respect to initial tumor volume, total dose after normalization for variations in fraction size, and to overall treatment time. Primary tumors were grouped into 4 sites, tongue (175), oral cavity including floor of mouth, faucial pillar, soft and hard palate and gingiva (210), tonsil (72) and buccal mucosa (41). Total doses of 60Co irradiation ranged from 30 Gy to 72 Gy, overall treatment times from 15 to 80 days and dose per fraction from 1.8 to 6 Gy. ⋯ Over the interval of about 30-55 days used in treating most of this series of patients, an increase of 60 cGy per day, on average, was required for a constant control rate. (2) The increase in dose was attributed to accelerated tumor clonogen growth rate. Such accelerated growth could be a major determinant of failure in protracted regimens. (3) The accelerated rate of regrowth was similar for all tumor sites and stages. (4) The dose for tumor control was relatively independent of variations in fraction size within a range of about 1.6 Gy to 3 Gy: the alpha/beta value in the linear quadratic isoeffect equation was at least 15 Gy. (5) Local control at the primary site required an average of about 3 Gy more for each increase in T stage. This increase most likely reflected an increased number of tumor clonogens, not a decreased tumor cell radiosensitivity. (6) The probability of control at the primary site was less likely if lymph nodes were positive, but this association was only shown to be statistically significant for primaries classified here as oral cavity and oropharynx, not tonsil, tongue or buccal mucosa. (7) After allowing for differences in treatment parameters, especially for heterogeneity in overall treatment times, tumor control probability increased steeply with increase in total dose. (8) A general principle of radiotherapy, at least for squamous carcinomas of head and neck, should be to deliver the desired fractionated dose regimen without unnecessary interruptions and in the shortest time compatible with no reduction in dose below that tolerated by the late-responding normal tissues.
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Int. J. Radiat. Oncol. Biol. Phys. · Feb 1989
Comparative StudyAge as a prognostic factor for patients treated with definitive irradiation for early stage breast cancer.
From 1977 to 1986, 88 breast cancers in 86 women age less than or equal to 35 years were treated with definitive irradiation following breast-conserving surgery. The records of these cases were reviewed and compared to 808 breast cancers in 798 women age greater than or equal to 36 years treated similarly during the same time period. All women had AJC clinical Stages I or II invasive carcinoma of the breast and had undergone an axillary surgical staging procedure to determine pathologic lymph node staging prior to receiving definitive radiotherapy. ⋯ Subset analyses also did not show a difference between the younger and older patients. Although longer follow-up will be needed to confirm these observations, our 5-year results show that younger patients less than or equal to age 35 do not have an adverse outcome in terms of survival, local control, or regional control when compared with older patients greater than or equal to age 36. Potential candidates for definitive irradiation following breast-conserving surgery should not be excluded for treatment solely on the basis of younger age less than or equal to 35 years.
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From 1976 to 1986, ten out of 1154 consecutive nasopharyngeal carcinoma (NPC) patients were found to have dermatomyositis (DM). Their clinical features and treatment results were analyzed. The skin manifestation was typical of DM and myopathy occurred in seven patients. ⋯ The complication of radiotherapy were unusually severe. Chronic radiation skin ulceration occurred in 2 patients and subcutaneous indurated fibrosis affecting both sides of neck occurred in all patients. Acute radiation mucositis was also prominent.
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Int. J. Radiat. Oncol. Biol. Phys. · Jan 1989
Prognosis following local or regional recurrence after conservative surgery and radiotherapy for early stage breast carcinoma.
Factors which influence patient prognosis following a breast recurrence or regional nodal recurrence after initial treatment of early-stage invasive breast carcinoma with conservative surgery and radiotherapy are not well known. Ninety patients treated at the Joint Center for Radiation Therapy treated from 1968-1981 had a recurrence in the treated breast before (84) or simultaneous with (6) distant metastases. Sixty-five patients had salvage mastectomy (median subsequent follow-up in patients without further disease, 32 months; range, 1-123 months). ⋯ Only 3 of these 10 (all with axillary node failures) did not have simultaneous distant metastases; they remain alive without evidence of further distant or local-regional recurrence following salvage treatment 1, 59, and 87 months after recurrence. We conclude that the great majority of the patients (88% in this series) who have a breast recurrence following initial conservative surgery and radiation therapy for early stage breast carcinoma will have disease limited to the breast clinically and tumors amenable to salvage mastectomy. Salvage mastectomy appears to be effective treatment for patients with an isolated breast recurrence, especially if the recurrence is predominantly or wholly non-invasive.