Retrospective study evaluating dental side effects of radiotherapy in patients treated for head and neck cancer

INTRODUCTION

Head and neck cancer squamous cell carcinoma (HNSCC) is the seventh most common cancer worldwide with around 600,000 new diagnosis each year. Nowadays, in locally advanced disease, radiotherapy (RT) play an important role, this with or without chemotherapy in organ preservation strategies. More specific for early stage localized disease, RT (or surgery) seems to give similar results on locoregional control (LRC) and choice is made according to the organ preservation issue. Despite the fact that technical improvements have been made to optimize the radiation dose delivery and minimize the normal tissue toxicity, RT is associated with potential early and late toxicities. Osteoradionecrosis of the jaw (ORNJ), especially seen after teeth extraction, is one of the associated toxicities and can significantly impair the patient's quality of life. Because of the fear of developing ORNJ, one is very reluctant to extract or place a dental implant post-radiotherapy, especially in high irradiation dose zones (>40 Gy). Hence, it is important to define teeth at risk of future extraction before initiating RT and to handle those in high-risk irradiation zones. In order to optimise extractions, we created a predictive model of the expected irradiation dose, and thus the need for extraction, to the teeth bearing bones. The aim of this study is to validate our model and to define the potential relationship between the radiation dose received by each tooth and the dental complications observed.

MATERIAL AND METHODS

Between March 2012 and March 2018, patients with HNSCC treated by intensity modulated RT were retrospectively analysed. The mean irradiation dose for each tooth was generated on the administered treatment plan by contouring each tooth separately on each dosimetric scan section using dedicated software (Eclipse, Varian). In order to validate our predictive model, we compared the actual generated/administered teeth irradiation doses with the irradiation doses predicted by our model.

RESULTS

Our predictive model was accurate in 69.6% of the cases. In 12.5% of cases the predicted dose was higher than the calculated dose and lower in 17,8% of the cases. A correct- or over-estimation (is the latter being clinically less worrying than an underestimated dose) was achieved in 82% of cases. For the 18% of cases underfitting, the mean margin of error was 5.7 Gy. No statistically significant association was found between the development of caries and doses to the teeth, doses to the parotid glands or dental hygiene. However, a significant association between dental irradiation at more than 40 Gy and the occurrence of dental fractures (p = 0.0002) were demonstrated.

CONCLUSIONS

Our predictive model seems to be 82% accurate for dose prediction, hence might be helpful for optimizing/minimizing prophylactic extractions. Indeed, following our model, professionals could decide not to extract damaged teeth in areas not at risk of ORNJ, lowering morbidity during and after RT. Contrary to the literature, no relationship was found between the occurrence of dental caries and parotid irradiation and the patient's oral hygiene. However, for the first time, a highly significant correlation between the occurrence of dental fracture and dental irradiation at more than 40 Gy was observed.

Phase III trial comparing two dose levels of epirubicin combined with cyclophosphamide with cyclophosphamide, methotrexate, and fluorouracil in node-positive breast cancer

PURPOSE

To compare a full-dose epirubicin-cyclophosphamide (HEC) regimen with classical cyclophosphamide, methotrexate, and fluorouracil (CMF) therapy and with a moderate-dose epirubicin-cyclophosphamide regimen (EC) in the adjuvant therapy of node-positive breast cancer.

PATIENTS AND METHODS

Node-positive breast cancer patients who were aged 70 years or younger were randomly allocated to one of the following treatments: CMF for six cycles (oral cyclophosphamide); EC for eight cycles (epirubicin 60 mg/m(2), cyclophosphamide 500 mg/m(2); day 1 every 3 weeks); and HEC for eight cycles (epirubicin 100 mg/m(2), cyclophosphamide 830 mg/m(2); day 1 every 3 weeks).

RESULTS

Two hundred fifty-five, 267, and 255 eligible patients were treated with CMF, EC, and HEC, respectively. Patient characteristics were well balanced among the three arms. One and three cases of congestive heart failure were reported in the EC and HEC arms, respectively. Three cases of acute myeloid leukemia were reported in the HEC arm. After 4 years of median follow-up, no statistically significant differences were observed between HEC and CMF (event-free survival [EFS]: hazards ratio [HR] = 0.96, 95% confidence interval [CI], 0.70 to 1.31, P =.80; distant-EFS: HR = 0.97, 95% CI, 0.70 to 1.34, P =.87; overall survival [OS]: HR = 0.97, 95% CI, 0.65 to 1.44, P =.87). HEC is more effective than EC (EFS: HR = 0.73, 95% CI, 0.54 to 0.99, P =.04; distant-EFS: HR = 0.75, 95% CI, 0.55 to 1.02, P =.06; OS HR = 0.69, 95% CI, 0.47 to 1.00, P =.05).

CONCLUSION

This three-arm study does not show an advantage in favor of an adequately dosed epirubicin-based regimen over classical CMF in the adjuvant therapy of node-positive pre- and postmenopausal women with breast cancer. Moreover, this study confirms that there is a dose-response curve for epirubicin in breast cancer adjuvant therapy.

[Pigmented villonodular synovitis: apropos of 3 cases]

Three cases of pigmented villonodular synovitis treated in recent years are described. One case presents a malignant transformation and raises the question of the benign character of these lesions. The therapeutic options are considered as well as the need for a larger series of patients to define therapeutic strategy.

[Why radiation for the postmastectomy patient?]

We can identify a subgroup of patients with a high risk of loco-regional relapse after mastectomy. When those patients are irradiated, their absolute loco-regional relapse risk drops for more than 10% with a relative risk reduction of 66% (p < 0.0001). The severe complication rate is below 1%. With earlier radiotherapy techniques, there was an excess in long term cardiac mortality among irradiated patients. Even if the breast specific survival was improved with radiotherapy, the overall survival was not better. Three recent randomised trials have shown that postmastectomy radiotherapy adds 10% survival benefit to an adjuvant systemic treatment. The impact of radiotherapy on overall survival is more pronounced for less advanced tumors.

[Late effects of radiations on the kidney]

Clinical radiation damage to the kidney are nowadays a rare event. Nevertheless, this organ is very sensitive to radiation and dose exceeding 15 Gy may induce severe and life threatening damage many years after the treatment. Prevention remains the best treatment through a precise localisation of the kidneys before any irradiation of the upper abdomen.

[Late effects of ionizing radiations on central nervous system, spinal cord and peripheral nerves]

Despite the lack of characteristic features, demyelination is the dominant feature of radiation induced late effects observed in cerebral nervous system and spinal cord. Acute, subacute and chronic changes are described in terms of pathological, clinical and radiological observations. Brain necrosis in adults is rarely noted below 60 Gy in conventional fractionation, while imaging changes are observed with lower doses. The most widely observed dose limit for the spinal cord is 45 Gy, in the absence of dose modifying chemotherapy. Tumor progression may be hard to distinguish from radiochemotherapy effects. The potential protective role of hyperfractionation is not yet clearly established. Peripheral nerves late effects, although rare, are described.

[Role of radiotherapy in benign diseases]

Radiation therapy of benign diseases represent a wide panel of indications. Some indications are clearly identified as treatment of arteriovenous malformations (AVM), hyperthyroid ophtalmopathy, postoperative heterotopic bone formations or keloid scars. Some indications are under evaluation as complications induced by neo-vessels of age-related macular degeneration or coronary restenosis after angioplasty. Some indications remain controversial with poor evidence of efficiency as treatment of bursitis, tendinitis or Dupuytren's disease. Some indications are now obsolete such as warts, or contra-indicated as treatment of infant and children.

[Contribution of curietherapy in the treatment of ENT tumors]

Considerable improvement has been made in head and neck brachytherapy since the historical radium era. This technique now allows a conservative treatment for buccal cavity and oropharynx tumors with a local control similar to surgery. When combined with external beam radiotherapy, brachytherapy allows to give a lesser dose to the critical organs. We review the brachytherapy techniques and results for various head and neck location.

[What is the role of radiotherapy in the treatment of breast cancer in 1995?]

In 1995, radiotherapy continues to remain one important component in the treatment of breast cancer both for the breast conserving approach and after a mastectomy in case of more locally advanced disease: it helps to improve the local control and so to safe more breast or to avoid a relapse in the mastectomy scar, a source of distress for the woman. Nevertheless, this modality requires a precise technique and integration with surgery and chemotherapy. Besides this curative approach, radiotherapy plays an important role in the treatment of brain or bone metastases where it is quite useful to improve the patient's quality of life.

Brachytherapy for lower lip epidermoid cancer: tumoral and treatment factors influencing recurrences and complications

From 1972 to 1991, 237 patients with squamous cell carcinoma of the lower lip were treated by exclusive LDR brachytherapy (192Ir). There were 158 T1, 61 T2, 17 T3 and 1 T4 with 231 N0, 3 N1 and 3 N2 patients. The actuarial values at 5 years for local and regional controls, overall and specific survivals were 95%, 91%, 74% and 91%. Salvage treatment increased local control up to 99% and regional control to 94%. No heterolabial recurrence has been observed since the entire lip is treated, even for small tumors. The regional control depends closely on the thickness of the labial tumor (> or = 1 cm, p < 0.0001). The healing of treatment-induced mucositis is sometimes delayed for thick tumors (> or = 1 cm, p = 0.015). Late complications are not related to tumoral thickness but to the treated thickness (> 1.4 cm, p = 0.018) and particularly to the thickness of normal tissue included in the 85% isodose (treated thickness - tumoral thickness > 0.4 cm, p = 0.025). The use of a leaded protection and low linear radioactivity wires (< 2 mCi/cm, < 8.6 muGy/h.m2/cm) especially for large target volumes is required to lessen late complications. Based on this review, we advocate exclusive brachytherapy for small and intermediate tumors, with elective bilateral submaxillary and submental dissection for thick, high grade or commissure tumors. Simple recommendations are made to assure quality of the brachytherapy treatment.