Adjuvant therapy

It is an «additional cancer treatment given after the primary treatment to lower the risk that (...) cancer will come back. Adjuvant therapy may include chemotherapy, radiation therapy, hormone therapy, targeted therapy, or biological therapy.»

Bibliographic reference: National Cancer Institute. (n.d.). NCI Dictionary of Cancer Terms. [online] Available at: https://www.cancer.gov/publications/dictionaries/cancer-terms?CdrID=45587 [Accessed 10 May 2017].

p53

It «(...) is one of the most commonly mutated tumor suppressors whose function is to regulate genes that control both cell cycle checkpoints and (...) apoptosis. Consequently, activation of p53 after irradiation can lead either to a block in proliferation or directly to cell death. (...) in unstressed normal cells, p53 is made continuously but is degraded and thus non-functional. Following DNA [deoxyribonucleic acid] damage, ATM [ataxia telangiectasia mutated] phosphorylates both p53 and MDM2 [murine double minute 2]. These events destabilize the p53-MDM2 interaction, and (...) p53 protein is no longer degraded. In addition to this stabilization, direct phosphorylation of p53 by ATM leads to its activation as a transcription factor and thus the upregulation of its many target genes [1].»

«Cells irradiated in the G1 phase are influenced by the action of p53. ATM protein is activated by double-strand DNA breaks and phosphorylates both MDM2 and p53. This leads to stabilization and activation of p53, which induces genes that can promote apoptosis (Bax [Bcl-2-associated X], Puma [p53 upregulated modulator of apoptosis]) and induces checkpoints. (...) cells are blocked at the G1/S border [1].»

Is has «(...) a mass of 53 kDa (hence its name); p53 protein is normally induced in cells having undergone DNA damage, (...); its principal effects are to stop the cell cycle and prevent the cell from undergoing mitosis; thus, DNA mutations/damage can either be repaired or a damaged cell can be eliminated from the organism, for example via apoptosis. p53 is also known as the guardian of the genome [2].»

Bibliographic references:

[1] Joiner, M. and Kogel, A. (2009). Basic clinical radiobiology. 1st ed. Boca Raton, Florida: CRC Press, p.17.

[2] Tortora, G., Bergmann, L., Lindh, M., Cervantes-Ruiperez, A., Dziadziuszko, R., Eckhardt, S., Lenz, H., Normanno, N., Perez, D., Scarpa, A., Syrigos, K., Tabernero, J. and Troiani, T. (2014). ESMO glossary in molecular biology of cancer. Viganello-Lugano, Switzerland: European Society for Medical Oncology, p.117.

Ratio

It's the relationship between two sets with different characteristics. The numerator is not included in the denominator. It is different from proportion.

Proportion

It's the relationship between the number of individuals who have a characteristic and the total population. The numerator is included in the denominator. It is different from ratio.

Symbols with short codes

In: Awesome Daily Staff. StumbleUpon. Stumbleuponcom. 2014. Available at: http://www.stumbleupon.com/su/2XigqH. Accessed February 25, 2017.

Lower urothelium (or lower transitional cell epithelium)

It coats the interior walls of the «urinary bladder, the ureters, the superior urethra, and the prostatic and ejaculatory ducts of the prostate.»

Bibliographic reference: Transitional epithelium. Enwikipediaorg. 2017. Available at: https://en.wikipedia.org/wiki/Transitional_epithelium. Accessed February 20, 2017.

Upper urothelium (or upper transitional cell epithelium)

It coats the interior walls of the pyelocaliceal cavities and ureter.

Bibliographic references: Rouprêt M, Babjuk M, Böhle A, et al. Upper Urinary Tract Urothelial Cell Carcinoma. EAU - European Association of Urology. 2017. Available at: https://uroweb.org/guideline/upper-urinary-tract-urothelial-cell-carcinoma/#3. Accessed February 20, 2017.

Urological organs

«The organs under the domain of urology include the kidneys, adrenal glands, ureters, urinary bladder, urethra, and the male reproductive organs (testes, epididymis, vas deferens, seminal vesicles, prostate, and penis).»

Bibliographic reference: Urology. Enwikipediaorg. 2016. Available at: https://en.wikipedia.org/wiki/Urology. Accessed February 20, 2017.

Redistribution

«Reassortment. The radiosensitivities of cells vary according to phases of the cell cycle.» «The duration of the cell cycle phases are: G1 = 1.5–14 h, S = 6–9 h, G2 = 1–5 h, and M = 0.5–1 h. The most sensitive are M and G2. The most resistant is S.» «Cells in the resistant phases of the cell cycle may progress into the sensitive phases in the next fraction, when radiation is given in fractions. Therefore, the probability of tumor cells to be exposed to radiation at sensitive phases increases. This probability will continue for the whole treatment, and the benefit from radiation will increase.»

Bibliographic reference: Beyzadeoglu M, Ozyigit G, Selek U. Radiation Oncology. 1st ed. Berlin: Springer; 2012:112-114.

¿Qué es la radioterapia?

Radiodermatitis or radiation dermatitis

It «is a cutaneous inflammatory reaction to exposure to biologically effective levels of ionizing radiation» [1]. It «can range from erythema to wet desquamation of the skin (tissue sloughing) in acute form; tissue atrophy, fibrosis, and permanent scarring in chronic form. Permanent changes in skin pigmentation can also occur» [2].

Source: Aistars J, Vehlow K. Radiation Dermatitis | Cancer Network. Cancernetworkcom. 2007. Available at: http://www.cancernetwork.com/oncology-nursing/radiation-dermatitis. Accessed March 30, 2018.

Source: Madhavan R. Radiation in oral cancers. Slidesharenet. 2017. Available at: https://www.slideshare.net/ramumpanicker/radiation-in-oral-cancers. Accessed March 30, 2018.

How to care for your skin during radiation therapy:

Bibliographic references:
[1] Radiodermatitis. (n.d.) Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. (2003). Retrieved January 7 2017 from http://medical-dictionary.thefreedictionary.com/radiodermatitis.
[2] Radiation dermatitis. (n.d.) Medical Dictionary for the Health Professions and Nursing. (2012). Retrieved January 7 2017 from http://medical-dictionary.thefreedictionary.com/radiation+dermatitis.

Missing data or missing values

In statistics, they «occur when no data value is stored for the variable in an observation [1].» They are «values of variables within data sets which are not known [2].»

Bibliographic references:

[1] Missing data [Internet]. En.wikipedia.org. 2016 [cited 19 November 2016]. Available from: https://en.wikipedia.org/wiki/Missing_data.

[2] Statistics Glossary: M [Internet]. Statsoft.com. 2016 [cited 19 November 2016]. Available from: http://www.statsoft.com/textbook/statistics-glossary/m#Missing values.

Standard error (SE)

«These are the SEs for the descriptive statistics. The SE gives some idea about the variability possible in the statistic [1].» It «(...) is a measure of the variability of a statistic. It is an estimate of the standard deviation of a sampling distribution [2].» It «(...) is the standard deviation of the sampling distribution of a statistic, (...) (Everitt BS, 2003, cited in [3]). «The SE of the mean [SEM] (...) is the theoretical standard deviation of all sample means of size n drawn from a population and depends on both the population variance (sigma) and the sample size (n) (...) [4].» «The SEM can be seen to depict the relationship between the dispersion of individual observations around the population mean (the standard deviation), and the dispersion of sample means around the population mean (the SE). Different samples drawn from that same population would in general have different values of the sample mean, so there is a distribution of sampled means (with its own mean and variance). (...) As the sample size increases, the dispersion of the sample means clusters more closely around the population mean and the SE decreases [3].» «The SE depends on three factors: the number of observations in the population (N), the number of observations in the sample (n), and the way that the random sample is chosen. If the population size is much larger than the sample size, then the sampling distribution has roughly the same SE, whether we sample with or without replacement . On the other hand, if the sample represents a significant fraction (say, 1/20) of the population size, the SE will be noticeably smaller, when we sample without replacement [2].» «The SE of the proportion (...) is the standard deviation of the distribution of the sample proportion over repeated samples [4].»

Source: Steve's Favorites. Pinterest. Available at: https://www.pinterest.pt/pin/419819996504206121/. Accessed November 3, 2017.

Bibliographic references:

[1] Annotated SPSS Output: Descriptive statistics [Internet]. Ats.ucla.edu. 2016 [cited 20 November 2016]. Available from: http://www.ats.ucla.edu/stat/spss/output/descriptives.htm.

[2] Statistics Dictionary [Internet]. Stattrek.com. 2016 [cited 20 November 2016]. Available from: http://stattrek.com/statistics/dictionary.aspx.

[3] Standard error [Internet]. En.wikipedia.org. 2016 [cited 20 November 2016]. Available from: https://en.wikipedia.org/wiki/Standard_error#cite_note-1.

[4] Statistics Glossary: S [Internet]. Statsoft.com. 2016 [cited 20 November 2016]. Available from: http://www.statsoft.com/textbook/statistics-glossary/s#Standard.

Confidence interval (CI)

It is «a range of values, calculated from the sample observations, that is believed, with a particular probability, to contain the true parameter value» [1]. It is used «to express the degree of uncertainty associated with a sample statistic. A confidence interval is an interval estimate combined with a probability statement.» One «might describe the interval estimate as a "95% confidence interval". This means that if» one «used the same sampling method to select different samples and computed an interval estimate for each sample,» one «would expect the true population parameter to fall within the interval estimates 95% of the time» [2]. «Precision is taken to be the narrowness of the confidence interval. (...) The interval estimate is an expression of the uncertainty surrounding the point estimate and derives mainly from sampling variation as well as measurement variation/error. In general, the degree of uncertainty is inversely related to the size of the study. On one hand, if a study is too small, the uncertainty may increase to a level considered to be undesirable or useless. On the other, as the study size increases, the degree of uncertainty decreases, and the interval estimate becomes narrower» [3]. «Confidence intervals are preferred to point estimates and to interval estimates, because only confidence intervals indicate the precision of the estimate and the uncertainty of the estimate» [2].

Bibliographic references:

[1] Everitt, B. and Skrondal, A. (2010). The Cambridge dictionary of statistics. 4th ed. Cambridge, UK: Cambridge University Press.

[2] Stattrek.com. (2016). Statistics Dictionary. [online] Available at: http://stattrek.com/statistics/dictionary.aspx [Accessed 13 Nov. 2016].

[3] Broeck, J. and Brestoff, J. (2013). Epidemiology: Principles and Practical Guidelines. 1st ed. Dordrecht: Springer.

Standard deviation (σ or s)

«The standard deviation of a population is denoted by σ and the standard deviation of a sample, by s [1].» It is a measure of dispersion or absolute variability [2,3] in original units (unit of measurement equal to that of the mean). It is the positive square root of the variance (σ² or s² or Var[X]). It «is useful as a measure of variation within a given set of data» [4]. «A small value of the standard deviation indicates that most values are close to the sample mean. A large value of the standard deviation indicates many values are far from the sample mean. Other words which are used to convey the concept of the standard deviation are “spread” and “scale.”» It is «the “typical” spread of observations about the sample mean [2].» It «is a numerical value used to indicate how widely individuals in a group vary. If individual observations vary greatly from the group mean, the standard deviation is big; and vice versa [1].»

Bibliographic references:
[1] Stattrek.com. (2016). Statistics Dictionary. [online] Available at: http://stattrek.com/statistics/dictionary.aspx [Accessed 13 Nov. 2016].
[2] Supino, P. and Borer, J. (2012). Principles of research methodology. 1st ed. New York, NY: Springer.
[3] Doi, S. and Williams, G. (2013). Methods of clinical epidemiology. 1st ed. Berlin: Springer.

[4] Daniel, W. and Cross, C. (2013). Biostatistics: a foundation for analysis in the health sciences. 10th ed. Danvers, Massachusetts, USA: John Wiley & Sons, Inc.

Boolean search

«A type of search allowing users to combine keywords with operators such as AND, NOT and OR to further produce more relevant results. For example, a Boolean search could be "hotel" AND "New York". This would limit the search results to only those documents containing the two keywords [1].» «Boolean searches allow you to combine words and phrases using the words AND, OR, NOT and NEAR (otherwise known as Boolean operators) to limit, widen, or define your search [2].»

In: Awesome Daily Staff. StumbleUpon. Stumbleuponcom. 2014. Available at: http://www.stumbleupon.com/su/2XigqH. Accessed February 25, 2017.

In: Wallace I. 9 Useful Browser Shorcuts. Stumbleuponcom. 2014. Available at: http://www.stumbleupon.com/su/30Xbyy/:G5nkn8+p:jlRVwzM!/infographicjournal.com/9-useful-browser-shorcuts. Accessed March 21, 2017.

Bibliographic references:

[1] Webopedia.com. (2016). What is Boolean Search? Webopedia Definition. [online] Available at: http://www.webopedia.com/TERM/B/Boolean_search.html [Accessed 31 Oct. 2016].

[2] Lifewire. (n.d.). What is a Boolean Search?. [online] Available at: https://www.lifewire.com/what-does-boolean-search-3481475 [Accessed 31 Oct. 2016].

Vx

Vx is the percent volume of the organ or target receiving ≥x Gy [1,3], or the volume covered by the isodose of x% [2].

Bibliographic references:
[1] Lu JY, Lin Z, Zheng J, et al. Dosimetric evaluation of a simple planning method for improving intensity-modulated radiotherapy for stage III lung cancer. Sci Rep. 2016 Mar 24;6:23543. Available at: https://dx.doi.org/10.1038/srep23543.
[2] Zhang T, Liang ZW, Han J, et al. Double-arc volumetric modulated therapy improves dose distribution compared to static gantry IMRT and 3D conformal radiotherapy for adjuvant therapy of gastric cancer. Radiat Oncol. 2015 May 19;10:114. Available at: https://dx.doi.org/10.1186/s13014-015-0420-x.

[3] Huang EX, Bradley JD, El Naqa I, et al. Modeling the risk of radiation-induced acute esophagitis for combined Washington University and RTOG trial 93-11 lung cancer patients. Int J Radiat Oncol Biol Phys. 2012 Apr 1;82(5):1674-9. Available at: https://dx.doi.org/10.1016%2Fj.ijrobp.2011.02.052.

MATHEWS OPEN ACCESS JOURNALS: Reirradiation of Skin Tumors

MATHEWS OPEN ACCESS JOURNALS: Reirradiation of Skin Tumors:                                                         www.mathewsopenaccess.com             http://www.mathewsopenaccess.com/PDF/Ca...

Tpot (potential doubling time without cell loss)

It describes the proliferation rate of the tissues, which can be measured from biopsies by flow cytometry after administration in situ to the patient of a deoxyribonucleic acid thymidine tracer [2]. "This is difficult to determine in vivo." It is "the time which the cell population of tumor doubles if there is no cell loss" [3]. Tp (potential doubling time or cell doubling time after cell loss) is a little shorter than Tpot (measured before the tumour has received any cytotoxic treatment) [1].

Pretreatment Tpot measured in human tumor biopsies [2].
Tumor	Median (days)	Range (days)
Larynx	4	2-19
Tongue	4-6	2-16
Mouth, cheek	3.4	2-15
Esophagus	5	2.5-20
Cervix	5	3-20
Rectum	5	3-18
Prostate	42	15-70
Breast	14	3-70

Bibliographic references:

[1] Fowler, JF. 21 years of Biologically Effective Dose. Br J Radiol. 2010 Jul; 83(991): 554–568. Available at: http://dx.doi.org/10.1259%2Fbjr%2F31372149.

[2] Fowler JF. The radiobiology of prostate cancer including new aspects of fractionated radiotherapy. Acta Oncol. 2005;44(3):265-76. Available at: http://dx.doi.org/10.1080/02841860410002824.
[3] The timely delivery of radical radiotherapy: standards and guidelines for the management of unscheduled treatment interruptions. (2008). 3rd ed. London, United Kingdom: Board of Faculty of Clinical Oncology, The Royal College of Radiologists. Available at: https://www.rcr.ac.uk/sites/default/files/publication/BFCO(08)6_Interruptions.pdf [Accessed 17 Jul. 2016].

K value or K factor

It is “the BED [biologically effective dose] equivalent of repopulation (in units of Gy/day)”, “the BED-equivalent repopulation factor” [1]. It is the "increase in dose required daily to obtain same biologic effect: recommended extra dose to add to total radiation dose for each day of prolongation, which can be given by increasing daily dose of remaining treatment". "Prolongation of overall treatment time due to unplanned interruptions during radiotherapy causes deleterious effect of accelerated repopulation of tumor clonogens. For the cancers of the head and neck, even a 1-day interruption resulted in a decrease in the local control rate by 1.4%" [9]. A “K value of 0.9 Gy/day represents the BED required each day (after Tdelay has been passed) to offset repopulation” [2]. It is “the biological dose per day required to compensate for on-going tumour cell repopulation. K is the BED equivalent of 1 days’ worth of repopulation” [3], “a factor used to determine the amount of radiation ‘wasted’ due to ongoing tumour repopulation” [4]. “If chemotherapy is able to completely inhibit repopulation then K=0 and would not be required” [1].
For head and neck treatments, it is “recommend K=0.1 Gy/day and Tdelay=0 in cases where the final overall times are less than 28 days” [1]. However, after this time, the K value is 0.5-0.7 Gy/day [9].

“There is at present very little data relating to K and Tdelay factors for other tumour types” [1].
“For cervix tumours, the time factors are probably around half those for head and neck tumours, i.e., 0.5 Gy/day” [1,5]. “For breast tumours, the K factors are likely to be around 0.3 Gy/day while for prostate tumours they are likely to be in the region 0.1–0.3 Gy/day, or even lower [1,6-8]”. “Little is known about the corresponding values of Tdelay” [1]. For transitional cell bladder carcinoma, K=0.36 Gy/day for a Tdelay=5-6 weeks [9]. For non-small cell lung cancer and a Tdaley>20 days, K=0.45 Gy/day [10,11]; but, for cases without mediastinal involvement, K=0.2 Gy/day [10].

Bibliographic references:

[1] Stamatakos, G. (2012). 2012 5th International Advanced Research Workshop on In Silico Oncology and Cancer Investigation (IARWISOCI). Piscataway, NJ: IEEE. Available at: http://www.5th-iarwisoci.iccs.ntua.gr/data/_uploaded/file/PROCEEDINGS_2012_5th_IARWISOCI_OPEN-ACCESS_VERSION_2012_DEC_05.pdf [Accessed 19 Jul. 2016].

[2] Dale RG, Hendry JH, Jones B, et al. Practical methods for compensating for missed treatment days in radiotherapy, with particularreference to head and neck schedules. Clin Oncol (R Coll Radiol). 2002 Oct;14(5):382-93. Available at: http://dx.doi.org/10.1053/clon.2002.0111.

[3] Dale RG, Jones B, Sinclair JA. Dose-equivalents of tumour repopulation during radiotherapy: the potential for confusion. Br J Radiol. 2000;73(872):892–894. Available at: http://dx.doi.org/10.1259/bjr.73.872.11026867.

[4] The timely delivery of radical radiotherapy: standards and guidelines for the management of unscheduled treatment interruptions. (2008). 3rd ed. London, United Kingdom: Board of Faculty of Clinical Oncology, The Royal College of Radiologists. Available at: https://www.rcr.ac.uk/sites/default/files/publication/BFCO(08)6_Interruptions.pdf [Accessed 17 Jul. 2016].

[5] Hendry JH, Bentzen SM, Dale RG, et al. A modelled comparison of the effect of using different ways to compensate for missed treatment days in radiotherapy. Clin Oncol. 1996;8(5):297–307. Available at: http://dx.doi.org/10.1016/s0936-6555(05)80715-0.

[6] Haustermans K, Fowler J, Geboes K, et al. Relationship between potential doubling time (Tpot), labelling index and duration of DNA synthesis in 60 oesophageal and 35 breast tumours: is it worthwhile to measure Tpot? Radiother Oncol. 1998;46(2):157–167. Available at: http://dx.doi.org/10.1016/s0167-8140(97)00164-3.

[7] Trott KR, Kummermehr J. What is known about tumour proliferation rates to choose between accelerated fractionation or hyperfractionation? Radiother Oncol. 1985;3(1):1–9. Available at: http://dx.doi.org/10.1016/s0167-8140(85)80002-5.

[8] King CR. What is the Tpot for prostate cancer? Radiobiological implications of the equivalent outcome with 125I or 103Pd. Int J Radiat Oncol Biol Phys. 2000;47(5):1165–1167. Available at: http://dx.doi.org/10.1016/s0360-3016(00)00543-5.
[9] Bese NS, Hendry J, Jeremic B. Effects of prolongation of overall treatment time due to unplanned interruptions during radiotherapy of different tumor sites and practical methods for compensation. Int J Radiat Oncol Biol Phys. 2007 Jul 1;68(3):654-61. Available at: http://dx.doi.org/10.1016/j.ijrobp.2007.03.010.
[10] Koukourakis M, Hlouverakis G, Kosma L, et al. The impact of overall treatment time on the results of radiotherapy for nonsmall cell lung carcinoma. Int J Radiat Oncol Biol Phys. 1996 Jan 15;34(2):315-22. Available at: http://dx.doi.org/10.1016/0360-3016(95)02102-7.
[11] Chen M, Jiang GL, Fu XL, et al. The impact of overall treatment time on outcomes in radiation therapy for non-small cell lung cancer. Lung Cancer. 2000 Apr;28(1):11-9. Available at: http://dx.doi.org/10.1016/S0169-5002(99)00113-0.