Las emociones y su impacto sobre el aprendizaje

RO-9.0 General Considerations

Radiation therapy is a common treatment modality in the management of head and neck cancers, both as a curative modality and as an adjuvant treatment following surgery. Fractionation can vary widely in head and neck radiotherapy. Conventional fractionation consists of daily fractions of 1.8 – 2.0 Gy (2.0 Gy daily is generally preferred,

particularly in cases where radiotherapy is the sole curative modality). When combined with chemotherapy, standard fractionation is typically utilized. Dose may vary within a plan from 54 to 72 Gy (for example, CTV low risk vs. gross disease) depending on the modality used. Maximum plan dose varies with overall stage and fractionation schedule. Altered fractionation, typically used without chemotherapy, may consist of either:

o Twice-daily fractions throughout the course of treatment (ie, hyperfractionation to total doses of 75 – 81 Gy using 1.2 – 1.25 twice daily fractions); or

o Twice-daily fractions during the boost portion of treatment only (ie, concomitant

boost accelerated therapy to a total dose of 72 Gy delivered over 6 weeks)

Although either IMRT or CRT may be used for most cases of head and neck cancer, IMRT is preferred in cases where treatment of the target volume with CRT may result in increased risks to the major salivary glands, temporal lobes, mandibles, auditory

structures and optic structures as compared to IMRT. Occult Primary Head and Neck Cancer

This designation refers to a squamous cell carcinoma presenting in cervical lymph node(s) and without evidence of either a primary disease site or distant disease,

suggestive of an undetected primary site in the upper aerodigestive tract. This clinical diagnosis is potentially curative. Conversely, discovery of any other pathology, a positive radiographic finding below the neck, and/or a clinical finding or history suggesting

another probable primary site suggests metastatic disease from a distant primary site. Metastatic disease is considered incurable, and therefore palliative therapy guidelines would apply. Requests for aggressive local control using higher curative dose

radiotherapy will be sent for Medical Director review. References

1. Lancet Oncol 2010; 11: 85-91

2. Br J Radiol 2009; 82: 585-94

3. Ann Oncol 2010; 21 Suppl 5:v184-6.: v184-v186

4. Radiother Oncol 2009; 92:4. Pignon JP, le Maître A, Maillard E, et al. Meta-analysis of

chemotherapy in head and neck cancer (MACH-NC): an update on 93 randomised trials and 17,346 patients.

RO-9.1 Definitive Radiotherapy

CRT or IMRT is appropriate for all head neck primary tumors treated with definitive intent except for early stage glottis, early stage supraglottic and lip cancer, where non- IMRT techniques are more appropriate for these small and simple target volumes. Conventional fractionation is appropriate for all stages of disease. Locally advanced disease is typically treated with concurrent chemoradiotherapy. Alternate fractionation schedules may be considered for advanced stage disease, particularly when chemotherapy is omitted.

CRT or IMRT

Early Stage Disease may receive up to 74 Gy in 37 fractions using conventional fractionation. Early stage larynx T1-2N0 may receive up to 66 Gy at 2 Gy per fraction.

Exception: for laryngeal cancers, the following dose schedules are appropriate and preferred in addition to standard fractionation as described above:

o Tis (carcinoma in situ): 56.25 – 58.5 Gy at 2.25 Gy per fraction

o T1 – 2, N0: 62.5 Gy at 2.5 Gy per fraction or 63 Gy at 2.25 Gy per fraction. Late Stage Disease may receive up to 74 Gy in 37 fractions using conventional fractionation.

Exception: for selected definitive cases treated with radiotherapy alone, doses up to ~ 81 Gy in 68 fractions using hyperfractionation and 72 Gy in 40 fractions using

concomitant boost fractionation may be used instead. References

1. Radiother Oncol 2007; 85: 156-70

2. Ann Oncol 2010; 21 Suppl 5:v184-6.: v184-v186

RO-9.2 Adjuvant Radiotherapy

Patients may require postoperative radiotherapy with any of the following risk factors for locoregional disease recurrence:

o close or positive margins o pathologic N2-3 disease o cartilage invasion

o nodal disease extracapsular extension (ECE) o nodal disease involving levels IV or V

o pathologic T3 or T4 primary disease

o perineural (PNI) or lymphovascular invasion (LVSI)

CRT or IMRT

Intermediate Risk patients with 1 above risk factor, excluding extracapsular extension should receive: 1.8 Gy fractions to a total dose of 57.6 Gy or 2 Gy fractions to a total dose of 60 Gy (maximum 32 fractions)

High Risk patients with either 2 or more above risk factors or extracapsular extension: 1.8 Gy fractions to a total dose of 63 Gy or 2 Gy fractions to a total dose of 66 Gy (maximum 35 fractions)

The benefit of postoperative concurrent chemoradiotherapy over postoperative RT alone has been demonstrated primarily for patients with positive surgical margins and/or

extracapsular extension (e.g. EORTC/RTOG trial data). RO-9.3 Brachytherapy

Brachytherapy as a monotherapy is appropriate for certain early stage lip and oral cavity tumors. Brachytherapy as a boost is appropriate after external beam radiotherapy for technically implantable lip and oral cavity tumors; brachytherapy boost for

nasopharyngeal tumors is also appropriate but using intracavitary techniques instead. External beam radiotherapy doses of 45–50 Gy using conventional fractionation are commonly used prior to brachytherapy boost. Brachytherapy dosing and fractionation may vary widely and are reviewed on a case-by-case basis. Oral cavity tumors with attachment to periosteum or with frank invasion of bone are contraindicated for brachytherapy given the high risk of osteoradionecrosis in this setting.

References

1. Radiother Oncol 2007; 85: 156-70

2. Ann Oncol 2010; 21 Suppl 5:v184-6.: v184-v186

3. Cancer 2009; 115: 5711-22

RADIATION ONCOLOGY GUIDELINES