24 Neoplastic - Larynx Flashcards
M/c site of laryngeal CA
glottis
What are the 7 different types of squamous cell aberrations occurring in the larynx?
- benign hyperplasia
- benign keratosis (no atypia)
- atypical hyperplasia
- keratosis with atypia or dysplasia
- intraepithelial carcinoma
- microinvasive SCCa
- invasive SCCa
What percent of pts with CIS of the VF will develop invasive SCCa after a single excisional bx?
1 in 6 (16.7%)
What is microinvasive SCCa of the VF
invades through BM but not into vocalis muscle
What is Ackerman’s tumor
Verrucous carcinoma, thought to be less radiosensitive and less likely to metastasize than SCCa
2 most imp factors predicting LN mets in laryngeal CA
tumor size and location
T/F: Once invasion of the laryngeal framework occurs, the ossified portions of cartilage have the least resistance to tumor spread
True
What percent of glottic tumors display perineural and vascular invasion
25%
What percent of pts w/ primary laryngeal CA will eventually develop a 2nd primary
10-20%
What is the stage of a transglottic tumor w/o VF fixation, cartilage invasion, or extension beyond the larynx
T2
What parts of the glottis are most difficult to treat with RT
Anterior commissure, posterior 1/3 of the VF
What percent of tumors at ant commissure and posterior 1/3 of VF will met to cervical LNs
25%
What are the 2 m/c reasons for tumor recurrence after hemilaryngectomy?
Inability to recognize the inferior tumor margin and spread of tumor through the cricothyroid membrane
What is the incidence of positive cervical nodes in pts with T3 glottic tumors
30-40%
Which type of laryngeal CA is most likely to met distally
Supraglottic
What is the m/c site of distant met from laryngeal CA
lungs
How does mets to lungs normally present
Multiple small lesions <3 mm that are difficult to detect on x-ray
Where does supraglottic CA most often begin
junction of epiglottis and false fold
What anatomic structure serves as a natural barrier to the inferior extension of supraglottic CA
Ventricle (embryologic development is completely separate from false cord)
Which kinds of supraglottic CA are more likely to extend inferiorly to the anterior commissure or ventricle – ulcerative or exophytic?
ulcerative
T/F: Stage I lesions of the supraglottis can be controlled equally well with RT or surgery
True
What is the risk of cervical mets in pts w/ T1, T2, T3, and T4 supraglottic tumors
20, 40, 60, 80%
What percent of pts undergoing supraglottic laryngectomy and u/l neck dissection will fail in the CONTRA neck
16% despite receiving RT to the area
What percent will fail if b/l neck dissections are performed
9%
What percent of laryngeal tumors are primarily subglottic
5%
What are the differences b/w primary and secondary subglottic tumors?
Primary tumors are less common, usually present with stridor or dyspnea and at a more advanced stage, and have a worse survival time than secondary tumors.
What is the primary site of lymph drainage for subglottic tumors
paratracheal nodes
Compared with supraglottic and glottic tumors, subglottic tumors are at a much higher risk for developing what?
Stomal recurrence
What is the tx of choice for primary subglottic CA?
TL, b/l ND, near total thyroid, paratracheal ND, postop RT to superior mediastinum and stoma; if the anterior cervical esophageal wall is involved, then laryngopharyngectomy with cervical esophagectomy instead of TL
What was the 1st published RCT for organ preservation in H&N CA
The VA trial for SCCa of the larynx
What were the VA tx arms and outcomes
- Surgery
- 2 cycles of cisplatinum and 5-FU
a. responders received a 3rd cycle followed by RT
b. Nonresponders had surgery +/- RT
No significant difference in survival among the 3 arms
What were the 3 major RCT on organ preservation as tx for laryngeal CA
VA, GETTEC, EORTC
What conclusions can be made based on meta-analysis of these 3 studies
The surgical patients had slightly higher (but not significant) survival advantage (6%). Among patients receiving chemotherapy, 58% were able to keep their larynx. Better outcomes were seen in patients with hypopharyngeal cancer who underwent chemotherapy than in those with laryngeal cancer.
What is the best organ-sparing tx for a pt with stage III SCCa of the supraglottis
Induction chemo followed by RT
What are the indications for postop RT after ND
multiple nodes or ECS
What is the significance of the number of pathologically + nodes on prognosis
Greater than 3 nodes is a neg prognostic indicator
T/F: chemosensitive tumors are usu radiosensitive
True
Which types of RT beams are used for superficial tumors and why
electrons; finite range spares deeper tissue
T/F: The dose of RT necessary to kill hypoxic cells is 2.5-3.0 times greater than than required to kill well-oxygenated cells
True, as free radical formation requires O2
T/F: Cells undergoing DNA synthesis in the S phase are much more radiosensitive than cells in other phases of cell cycle
False; they are much more radioresistant in the S phase
Which type of CA is most sensitive to RT: exophytic, infiltrative, or ulcerated?
Exophytic
When, after RT is a + bx a reliable indicator of persistent dz
3 mo post-tx
How do RT failures differ from surgical failures in site of recurrence
RT failures often occur in the center of areas that were grossly involved w/ CA initially, whereas surgical failures often occur at periphery of the original tumor
What is the conventional fractionated RT
1.8-2.5 Gy every day, five fractions every week, for 4-8 weeks (total 60-65 Gy for small tumors, 65-70 Gy for larger tumors)
How is altered fractionated schedule different?
Lower dose per fraction, 2 or more fractions every day, decreased overall tx time, with total dose same or higher
What are the 2 categories of altered fractionation
accelerated and hyperfractionated
What is the difference
Accelerated: Total dose is the same as conventional treatment, but overall treatment time is decreased.
Hyperfractionated: Overall treatment time is the same as conventional treatment, but total dose is increased, dose per fraction is decreased, and the number of fractions is increased.
What impact does hyperfractionation have on locoregional control and survival rates compared with conventional therapy
significantly higher locoregional control and survival rates
What were the results from the EORTC 22851 study comparing accelerated split-course XRT with conventional XRT
Accelerated course resulted in significantly higher late SE w/o significant locoregional control or survival advantage
What were results of RTOG 9003 study evaluating acclerated tx w/ concomitant boost
Significantly higher locoregional control and survival rates w/ somewhat higher rate of late SE compared w/ conventional RT
RT is not as effective for tumors with which characteristics
High volume, cartilage destroying, with bulky LN dz
What is the max dose of RT to spinal cord
45 Gy (or inc risk of radiation myelitis)
Advantages of planned preop RT
- Unresectable tumors may be made resectable
- Extent of surgical resection may be diminished
- Tx portals preop are usu smaller than those used postop
- Microscopic dz is more radiosensitive preop due to better blood supply
- Viability of tumor cells that may be disseminated by surgical manipulation is diminished
Disadvantages of planned preop RT
- Wound healing is more difficult
- Dose that can be safelly delivered preop is less than that which can be given postop
Advantages of postop RT
- Anatomic extent of tumor can be determined surgically making it easier to define the tx portals required
- Greater dose can be given postop
- Total dose can be determined on basis of residual tumor burden after surgery
- Surgical resection is easier and healing is better in nonirradiated tissue
T/F: RT should not be delayed in the presence of a fistula, open wound, or bony exposure
True: as long as carotid artery is not exposed, RT should never be delayed
What is the primary role of concomitant CRT in tx of H&N CA
Improve local and regional control in pts w/ unresectable dz
What is the primary problem with concomitant CRT
Acute toxicities are markedly increased and result in pt noncompliance
Which pts are more likely to benefit from adjuvant chemo
Those with high risk tumors (ECS, CIS, close surgical margins) and those with locally advanced NP CA
What were the 3 tx arms in H&N Intergroup R91-11 trial
Which arm had best outcome
- Induction chemo (cisplatin and 5-FU) vs
- RT alone vs
- Concomitant cisplatin and RT
for tx of potentially resectable stage III and IV CA of the larynx
Concomitant CRT significantly increased the time to TL
What can be said of presence of level V cervical mets from SCCa of the upper aerodigestive tract?
Uncommon (7%) and if present most likely to occur in presence of level IV mets
